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OPA MCP Server

CI CodeQL npm version Docker pulls License: MIT Node.js

A Model Context Protocol (MCP) server that turns any MCP-compatible client (Claude Desktop, Claude Code, Cursor, VS Code, Windsurf, Zed, and others) into a first-class Open Policy Agent and Rego authoring environment.

┌────────────────────┐  MCP / stdio  ┌─────────────────┐  spawn / HTTP  ┌──────────────────┐
│  Claude · Cursor · │ ────────────▶ │  @orygn/opa-mcp │ ─────────────▶ │  opa · regal ·   │
│   VS Code · ...    │ ◀──────────── │                 │ ◀───────────── │  OPA REST API    │
└────────────────────┘   32 tools    └─────────────────┘                └──────────────────┘

Status: v0.1.0. First stable release. Tool surface, error codes, and environment variables follow SemVer from this version forward.


Table of contents

Related MCP server: kubernetes-mcp

What you can do with it

Once an MCP client is connected, an agent can:

  • Author Rego. Generate, format, and refactor policies. The server runs the real opa fmt and opa parse so output is byte-identical to what you'd get on the command line, and regal (optional) surfaces idiomatic suggestions.

  • Evaluate against data. Run a query against a policy and an input document. Optional --explain, --profile, and --coverage flags surface execution traces, hot rules, and per-line coverage.

  • Debug a deny. rego_explain_decision walks the agent through every rule that fired (and every one that didn't), so it can answer "why was this rejected" without you reading the trace by hand.

  • Manage policies on a running OPA. List, get, put, delete policies on an OPA server through its REST API. Works against a local opa run --server or a production deployment with bearer-token auth.

  • Build & sign bundles. Package a directory of policies into a deployable bundle, optionally signing it. Output is a regular .tar.gz the agent can hand to your delivery system.

  • Lint. rego_lint runs Regal across a directory or a single file and returns categorized findings (style, bugs, performance, idioms).

A walk-through of a typical session lives in Cookbook.

Why this MCP

OPA already has a perfectly good CLI and REST API. So why an MCP wrapper?

  • Schema-shaped tool surface. An agent calling rego_eval gets a validated input schema, a structured output envelope, and stable error codes, instead of parsing free-form CLI text and inventing its own failure taxonomy. That alone makes Rego usable to an agent the way a language server makes a language usable to an IDE.

  • Higher-level helpers. rego_explain_decision, rego_generate_test_skeleton, rego_describe_policy, and rego_suggest_fix compose the lower-level primitives into the tasks agents are actually asked to do. They don't exist in the OPA CLI.

  • Curated knowledge. The bundled MCP resources expose the OPA built-in function catalog, the official Rego style guide (formatted for LLMs), and a curated pattern library covering RBAC, ABAC, Kubernetes admission, IaC gates, API authz, and rate limiting, so the agent has authoritative context without needing to scrape it.

  • Safety boundaries the agent can rely on. Path allow-list, subprocess timeouts, response-size caps, and an explicit HTTP_SEND_BLOCKED error for the dangerous OPA built-ins. Defaults are conservative; running the server doesn't quietly grant the agent more reach than the operator intended.

If you've ever watched an agent fight opa eval's argument order, you'll recognize the gap this fills.

Install

The server runs locally over stdio. Pick the install path that matches your client.

Claude Desktop / Claude Code

The fastest path is the Smithery one-liner:

npx -y @smithery/cli install @orygn/opa-mcp --client claude

Or download opa-mcp.mcpb from the latest release and double-click it.

If you prefer to edit claude_desktop_config.json by hand, the snippet lives in examples/claude-desktop.json:

{
  "mcpServers": {
    "opa": {
      "command": "npx",
      "args": ["-y", "@orygn/opa-mcp"],
      "env": {
        "OPA_BINARY": "/usr/local/bin/opa",
        "REGAL_BINARY": "/usr/local/bin/regal",
        "OPA_URL": "http://localhost:8181",
        "OPA_MCP_ALLOWED_PATHS": "/path/to/your/policies"
      }
    }
  }
}

Replace the /usr/local/bin/... paths with your real ones. See the first-time install gotcha below. Windows users substitute C:\\path\\to\\opa.exe.

Cursor

Drop examples/cursor.json into either .cursor/mcp.json (project-scoped) or ~/.cursor/mcp.json (user-scoped).

VS Code (GitHub Copilot Chat)

Drop examples/vscode.json into .vscode/mcp.json, or paste the servers block into your user settings.json under mcp.servers.

Windsurf, Zed, and others

See examples/ for a full set of drop-in configs.

Manual install (any MCP client)

npm install -g @orygn/opa-mcp
opa-mcp --version

then point your client at the opa-mcp binary.

Docker

docker pull orygn/opa-mcp:latest
docker run --rm -i \
  -v /path/to/your/policies:/policies:ro \
  -e OPA_MCP_ALLOWED_PATHS=/policies \
  orygn/opa-mcp

The image is multi-arch (linux/amd64, linux/arm64), bundles pinned versions of opa and regal, and runs as a non-root user. No host install of OPA or Regal is required.

⚠ First-time install gotcha (read this if you used npx or the global install)

If your client's PATH doesn't include the directory where opa lives (this happens with Claude Desktop on Windows and macOS by default), the server boots fine but every tool call returns OPA_BINARY_NOT_FOUND.

Fix: add OPA_BINARY and REGAL_BINARY env entries to your client config with the absolute path to each binary. The example configs under examples/ ship with placeholder paths you replace. Find the real paths with:

which opa && which regal                                    # macOS / Linux
Get-Command opa, regal | Select-Object Source              # Windows

This does not affect the Docker or MCPB install paths; those ship opa and regal inside the bundle and bypass PATH entirely. See Troubleshooting for full detail.

Configuration

The server reads its configuration from environment variables. Every variable is optional; defaults are sensible for a local OPA on http://localhost:8181.

Variable

Default

Purpose

OPA_URL

http://localhost:8181

Base URL of an OPA REST endpoint, used by opa_* tools.

OPA_TOKEN

(unset)

Bearer token for OPA, if your instance requires auth. Treated as a secret. Never echoed in logs or tool responses.

OPA_BINARY

opa (on PATH)

Path to the opa CLI, used by rego_* tools.

REGAL_BINARY

regal (on PATH)

Path to the regal linter. Only required by rego_lint.

OPA_MCP_ALLOWED_PATHS

(unset)

Comma- or semicolon-separated list of directories the server is allowed to read policies from. When unset, file-based tools refuse to read from disk.

OPA_MCP_LOG_FILE

<tmpdir>/orygn-opa-mcp.log

Path the server appends logs to. The server never writes to stdout; that channel is reserved for the MCP protocol.

OPA_MCP_LOG_LEVEL

info

One of debug, info, warn, error.

OPA_MCP_MAX_RESPONSE_BYTES

100000

Hard cap on a single tool response. Larger payloads are truncated with a __truncated: true marker.

OPA_MCP_TIMEOUT_MS

30000

Hard timeout for any spawned subprocess (opa, regal). After this, the child gets SIGTERM and then SIGKILL.

OPA_MCP_HTTP_TIMEOUT_MS

15000

Timeout for HTTP requests to the OPA REST API.

Paths in OPA_MCP_ALLOWED_PATHS and the *_BINARY variables must be absolute. Relative paths and missing binaries are rejected with structured errors.

Tool reference

Every tool returns a JSON envelope:

{ "ok": true, "data": { ... }, "warnings": [ ... ] }
{ "ok": false, "error": { "code": "INVALID_REGO", "message": "...", "hint": "...", "details": { ... } } }

Stable error codes: INVALID_INPUT, INVALID_REGO, INVALID_BUNDLE, EVAL_ERROR, OPA_BINARY_NOT_FOUND, REGAL_NOT_FOUND, REGAL_VERSION_TOO_OLD, OPA_UNREACHABLE, OPA_AUTH_FAILED, POLICY_NOT_FOUND, PATH_NOT_ALLOWED, PATH_NOT_FOUND, DEPENDENCY_CONFLICT, NO_TESTS_FOUND, HTTP_SEND_BLOCKED, TIMEOUT, UNKNOWN_ERROR.

Category A: Authoring & static analysis

Operate on Rego source code without needing a running OPA server. Wrap opa fmt, opa parse, opa check, opa inspect, opa capabilities, opa deps, and regal.

Tool

What it does

rego_format

Format Rego source. Wraps opa fmt. Idempotent.

rego_check

Type-check and validate Rego. Wraps opa check.

rego_lint

Run Regal across a file or directory. Returns findings grouped by category. Requires regal on PATH or REGAL_BINARY set.

rego_parse_ast

Parse Rego to AST JSON. Wraps opa parse.

rego_inspect

Inspect a bundle or directory: packages, rules, annotations. Wraps opa inspect.

rego_capabilities

Return the capabilities (built-ins, future keywords) understood by the bundled OPA.

rego_deps

Static dependency analysis: rule-level data references and cross-package calls.

// Input
{
  "source": "package x\nallow{input.user==\"admin\"}"
}

// Output (ok)
{
  "ok": true,
  "data": {
    "formatted": "package x\n\nallow if input.user == \"admin\"\n",
    "changed": true
  }
}
// Input
{
  "source": "package x\nallow if y",
  "strict": true
}

// Output (error path; the JSON diagnostics arrive on stderr from opa)
{
  "ok": true,
  "data": {
    "valid": false,
    "errors": [
      {
        "code": "rego_unsafe_var_error",
        "message": "var y is unsafe",
        "location": { "row": 2, "col": 11 }
      }
    ]
  }
}

Category B: Evaluation & testing

Run a query against a policy and input. Wrap opa eval, opa test, and opa bench.

Tool

What it does

rego_eval

Evaluate a query against a policy and input. The bread-and-butter tool.

rego_eval_with_explain

Evaluate with --explain=full and return a structured trace.

rego_eval_with_profile

Evaluate with --profile and return per-rule timing and evaluation counts.

rego_eval_with_coverage

Evaluate with --coverage and return per-line coverage.

rego_test

Run opa test over a directory. Returns pass/fail per test, with optional coverage.

rego_bench

Run opa bench and return statistical timing data.

rego_compile_query

Partially evaluate a query against a policy.

// Input
{
  "query": "data.rbac.allow",
  "source": "package rbac\nimport rego.v1\nallow if input.role == \"admin\"",
  "input": { "role": "admin" }
}

// Output
{
  "ok": true,
  "data": {
    "result": [{ "expressions": [{ "value": true, "text": "data.rbac.allow", "location": { "row": 1, "col": 1 } }] }]
  }
}

Category C: Bundle operations

Package and sign deployable bundles. Wrap opa build and opa sign.

Tool

What it does

opa_bundle_build

Build a .tar.gz bundle from a policy directory. Supports optimize and revision.

opa_bundle_sign

Sign a bundle with a private key. Returns .signatures.json content.

Category D: OPA server management

Talk to a running OPA server over its REST API. Require OPA_URL to point at a reachable server.

Tool

What it does

opa_list_policies

List policies registered on the server.

opa_get_policy

Get a single policy by ID.

opa_put_policy

Upload or replace a policy.

opa_delete_policy

Delete a policy by ID.

opa_get_data

Read a path from the data hierarchy.

opa_put_data

Write to a path in the data hierarchy.

opa_patch_data

Apply a JSON Patch to the data hierarchy.

opa_query_decision

POST to a /v1/data/... decision endpoint with input.

opa_compile_query

Partially evaluate a query against the running server.

opa_health

Liveness / readiness check.

opa_status

Bundle / decision-log status.

opa_config

Server configuration (without secrets).

Category E: Higher-level helpers

The differentiation surface. These compose lower-level primitives into the tasks agents are actually asked to do.

Tool

What it does

rego_explain_decision

Walk through every rule that fired (and didn't) for a given query. Wraps rego_eval_with_explain and produces a step-by-step natural-language trace.

rego_generate_test_skeleton

Given a policy, generate a _test.rego skeleton covering each rule.

rego_describe_policy

Summarize what a policy does, its inputs, decisions, and assumptions.

rego_suggest_fix

For a failed rego_check or rego_lint, propose minimal patches.

Prompts

Three MCP prompts ship with the server. Clients surface them as slash commands or workflow templates.

Prompt

Purpose

policy_authoring_assistant

Walks the agent through writing a new policy: ask about the decision surface, draft, review, format, lint, test.

policy_review_checklist

Review checklist for an existing policy: completeness, edge cases, performance, security pitfalls.

decision_debugging_workflow

Diagnostic flow when a decision is unexpected: gather input, run with explain, isolate the rule, propose a fix.

Resources

Three MCP resources expose curated reference data the agent can read at any time.

Resource URI

What's there

opa://builtins

Categorized OPA built-in function reference, derived at read time from opa capabilities --current. Security-sensitive functions (http.send, crypto.x509.*, opa.runtime) are flagged.

opa://style-guide

Condensed Rego style guide, formatted for LLM consumption.

opa://patterns

Curated common-pattern library: RBAC, ABAC, Kubernetes admission, IaC gates, API authz, rate limiting. Each pattern includes when-to-use, full Rego, a test, and common pitfalls.

Cookbook

A few session shapes that the tool set was designed for.

"Help me write a policy"

You: I need an authz policy: editors can read/write, viewers can only read,
     admins can do anything.

Agent: I'll draft it. (calls rego_format on a draft, then rego_check, then
       rego_lint)

Agent: Here's the policy. I've also generated a test file with cases for
       each role. (calls rego_generate_test_skeleton, then rego_test)

Agent: All 9 tests pass. Want me to save it to <path>?

"Why was this denied?"

You: This API call is being denied and I don't know why.
     [pastes input.json]

Agent: (calls rego_explain_decision against your local policy with that input)

Agent: The deny comes from rule `forbid_anonymous_writes` at line 17.
       Specifically, `input.user` is null and the request method is "POST".
       The rule fires, which causes the default deny. To allow this, you'd
       need either an authenticated user or a policy exception for this
       endpoint.

"Push this policy to staging OPA"

You: Push policies/rbac.rego to the staging OPA server, but first lint and
     test it.

Agent: (rego_lint → 2 style warnings, no errors)
       (rego_test on policies/ → all pass)
       (opa_put_policy with id="rbac" against $OPA_URL)
       (opa_get_policy to verify)

Agent: Done. Policy `rbac` is live on staging at $OPA_URL.

Architecture

┌──────────────────────────────────── @orygn/opa-mcp ───────────────────────────────────┐
│                                                                                       │
│   src/server.ts ──── McpServer (stdio) ─── tool / prompt / resource registries        │
│                          │                                                            │
│                          ├── tools/authoring/         ─┐                              │
│                          ├── tools/evaluation/        ─┤                              │
│                          ├── tools/bundles/           ─┼─── lib/opa-cli.ts ──┐        │
│                          ├── tools/server-management/ ─┤                     │        │
│                          ├── tools/helpers/           ─┘                     │        │
│                          │                                                   ▼        │
│                          │                              lib/subprocess.ts ──┴── opa   │
│                          │                              lib/regal-cli.ts   ───── regal│
│                          │                              lib/opa-client.ts  ───── HTTP │
│                          │                                                            │
│                          └── lib/output.ts (envelope + truncation)                    │
│                              lib/security.ts (path allow-list)                        │
│                              lib/errors.ts (structured failures)                      │
│                              lib/logger.ts (file-only, never stdout)                  │
└───────────────────────────────────────────────────────────────────────────────────────┘

Three things worth knowing if you're going to operate this:

  1. stdout is the protocol channel. The server logs to a file via lib/logger.ts and never writes to stdout. If you see stray stdout bytes, the client disconnects; the MCP transport layer is strict.

  2. No tool throws. Every tool catches its own exceptions and returns a structured { ok: false, error: ... } envelope. The agent sees a stable error vocabulary, not a stack trace.

  3. Subprocesses are tightly bounded. lib/subprocess.ts runs opa and regal with shell: false, a hard timeout, and SIGTERM-then- SIGKILL escalation. There is no path through the server where an agent can construct a shell command.

Security

This server is designed to run locally, started by an MCP client on the user's own machine, communicating over stdio. It is not designed to be exposed on the network.

  • File-based tools refuse to read anything outside OPA_MCP_ALLOWED_PATHS. When that variable is unset, file tools return PATH_NOT_ALLOWED.

  • Subprocesses run with shell: false and a hard timeout.

  • OPA_TOKEN is never echoed in tool responses or log entries.

  • Releases are published with npm provenance; the Docker image is built reproducibly from the committed Dockerfile.

To report a vulnerability, follow SECURITY.md. Please do not open a public issue for security problems.

Troubleshooting

Common issues, fast fixes.

OPA_BINARY_NOT_FOUND even though opa is installed. (most common first-day issue, read this first)

MCP clients (notably Claude Desktop on Windows and macOS) launch the server with a deliberately reduced PATH that omits user-local bin directories, even ones that work fine in your interactive shell. The binary is on your machine; the spawned MCP server just can't see it.

Find the absolute path to opa:

# macOS / Linux
which opa
# → /usr/local/bin/opa  (or /opt/homebrew/bin/opa, or ~/.local/bin/opa)
# Windows
Get-Command opa | Select-Object -ExpandProperty Source
# → C:\Users\you\bin\opa.exe  (or wherever)

Then set OPA_BINARY to that absolute path in your client's MCP env block. Same for REGAL_BINARY if you use the rego_lint tool. The examples/ configs already include both env vars; just edit the placeholder paths.

This issue does not affect the Docker or MCPB install paths. Those bundle opa and regal and bypass PATH entirely.

The server starts, then the client says "disconnected."

The most likely cause is something in the process writing to stdout besides MCP frames. If you've added a custom tool, check that no library it calls prints to stdout. The fixed-position safety net is lib/logger.ts. Use it, not console.log.

PATH_NOT_ALLOWED on a file under my project.

OPA_MCP_ALLOWED_PATHS is empty by default. Set it to the absolute path(s) you want the server to read from, comma-separated.

OPA_UNREACHABLE when calling opa_* tools.

OPA_URL (default http://localhost:8181) must point at a running OPA server (opa run --server ...). Check with curl $OPA_URL/health.

Regal "version too old."

We track the current Regal release. If REGAL_VERSION_TOO_OLD fires, upgrade Regal: brew upgrade regal or download from the Regal releases page.

directory-package-mismatch violation when linting inline source.

When you pass source rather than paths to rego_lint, Regal sees a randomized temp-file path that can't possibly match your declared package path. The diagnostic is an artifact of inline linting, not a real issue. Disable the rule for inline workflows or lint via paths against the real on-disk file when you want canonical signal.

Where are the logs?

Default location is <OS-tmpdir>/orygn-opa-mcp.log. That's typically /tmp/orygn-opa-mcp.log on Linux/macOS or %TEMP%\orygn-opa-mcp.log on Windows. Set OPA_MCP_LOG_FILE to override, and OPA_MCP_LOG_LEVEL=debug to widen the firehose.

Development

git clone https://github.com/OrygnsCode/opa-mcp-server.git
cd opa-mcp-server
npm install
npm run dev

Common commands:

npm run lint              # ESLint
npm run typecheck         # tsc --noEmit
npm test                  # unit tests (Vitest)
npm run test:coverage     # unit + coverage report
npm run test:integration  # against real opa + regal binaries
npm run build             # compile to dist/

CI runs lint, typecheck, build, and unit tests on every push and PR across Ubuntu, macOS, and Windows on Node 20 and 22. Integration tests run on Linux against pinned opa and regal releases.

For the full contributor workflow (adding tools, naming conventions, logging discipline, release process), see CONTRIBUTING.md.

Versioning & support

This project follows Semantic Versioning. The public surface for SemVer purposes is the set of registered tools, prompts, and resources, their input/output schemas, the recognized environment variables, and the CLI entry point.

Breaking changes will be:

  • announced in CHANGELOG.md under a new major version,

  • preceded by at least one minor release with a deprecation warning,

  • accompanied by a migration note in the release announcement.

Pinned versions of the upstream toolchain (opa and regal) are treated as part of the build, not as a dependency the operator manages. The Dockerfile, MCPB bundle, and CI all use the same pin; bumps go through Dependabot or a manual PR.

License

MIT © Orygn LLC

@orygn/opa-mcp is an independent project. It is not affiliated with, endorsed by, or sponsored by the Open Policy Agent project, the Cloud Native Computing Foundation, Styra, or Anthropic. "Open Policy Agent" and "Rego" are trademarks of their respective owners. "Model Context Protocol" is a trademark of Anthropic, PBC.

Available Tools

52 tools
conftest_pullConftest pullA
DestructiveIdempotent

Download Rego policies from an OCI registry or Git repository into a local directory using conftest pull. Use this to hydrate a local policy/ directory before running conftest_test. Requires conftest on PATH or CONFTEST_BINARY set. The policy directory must be inside OPA_MCP_ALLOWED_PATHS. SECURITY: pulled policies are arbitrary Rego source that will be executed by conftest_test. Only pull from registries or repositories you own or explicitly trust -- malicious policy code can use OPA built-ins (http.send, opa.runtime) to exfiltrate data or make outbound network requests when the tests run.

ParametersJSON Schema
NameRequiredDescriptionDefault
urlYesPolicy URL to pull. Supported schemes: `oci://registry/repo:tag` (OCI registry), `github.com/org/repo//path` (GitHub subdirectory), `git::https://example.com/repo//path` (generic Git). See https://www.conftest.dev/sharing/ for the full URL syntax.
policyNoLocal directory where the pulled policies will be written. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Omitted, it falls back to `policy` in the working directory of the server process, the conftest convention, which must itself sit inside an allowed root. The directory is emptied before the pull, so do not point it at one holding anything you want to keep.

TDQS

A4.5/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the annotations, the description discloses that the target directory is emptied before the pull, warns that pulled policies are arbitrary executable Rego with exfiltration/network risks, and notes the external binary dependency and path restrictions. This is substantial value added on top of destructiveHint and readOnlyHint.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the main action and each subsequent sentence covers a distinct aspect: use case, prerequisite, path constraint, and security warning. No filler or redundancy; the security warning earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a side-effectful tool with no output schema, the description covers purpose, prerequisites, destructive side effects, security implications, and path constraints. An agent has everything needed to decide whether to call it and to call it safely.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema description coverage, the schema already documents the url schemes and the policy directory fallback and emptying behavior. The tool description doesn't add new parameter-level meaning beyond restating that the policy directory must be inside allowed paths, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific action: 'Download Rego policies from an OCI registry or Git repository into a local directory using conftest pull.' It identifies the resource, destination, and direction, and it distinguishes itself from the sibling conftest_push by direction and from conftest_test by sequencing ('hydrate ... before running conftest_test').

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit usage context: 'Use this to hydrate a local policy/ directory before running conftest_test' and states prerequisites (conftest on PATH or CONFTEST_BINARY, OPA_MCP_ALLOWED_PATHS). It does not explicitly name an alternative to use instead, but the download-vs-push contrast and the sequencing with conftest_test provide clear context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

conftest_pushConftest pushA
Destructive

Package the local Rego policy directory as an OCI artifact and push it to a registry using conftest push. Registry credentials must be pre-configured in the host environment (docker login, ORAS keychain, etc.) -- this tool never handles credentials. The policy directory must be inside OPA_MCP_ALLOWED_PATHS. Requires conftest on PATH or CONFTEST_BINARY set.

ParametersJSON Schema
NameRequiredDescriptionDefault
policyNoPath to the local directory containing Rego policies to push. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS) and must exist. Omitted, it falls back to `policy` in the working directory of the server process, the conftest convention, which must itself sit inside an allowed root.
repositoryYesOCI repository URL to push policies to (e.g. `ghcr.io/my-org/policies:latest`). Registry credentials must already be configured in the host environment (via `docker login`, ORAS keychain, or REGISTRY_AUTH_FILE). This tool does not accept or store registry credentials.

TDQS

A4.3/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark the tool as non-read-only and destructive; the description adds meaningful context beyond that: it never handles credentials, registry auth must be pre-configured externally, the policy path must be inside allowed roots, and `conftest` must be on PATH or `CONFTEST_BINARY` set. It could add overwrite/tag-replacement semantics, but the description meaningfully enriches the annotation profile.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences, each load-bearing: the main action, the credential-handling caveat, and the path/binary prerequisites. Information is front-loaded and there is no filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a destructive push operation with no output schema, the description covers the command, target registry, credential model, path restrictions, and binary prerequisite. An agent has enough information to decide whether it can invoke the tool and what side effects to expect.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and both parameter descriptions already document path constraints, fallback behavior, allowed roots, and registry credential requirements. The tool description mostly restates these, adding only environment-level context like `CONFTEST_BINARY` rather than new parameter-level meaning, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb and resource pair: package the local Rego policy directory as an OCI artifact and push it to a registry using `conftest push`. This clearly distinguishes it from siblings like `conftest_pull`, `conftest_test`, and the various rego_ inspection tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It clearly states when to use the tool (when publishing a policy directory as an OCI artifact) and lays out prerequisites: pre-configured registry credentials, the policy path inside OPA_MCP_ALLOWED_PATHS, and `conftest` availability. It does not explicitly name alternatives or exclusions, but the push-scope and inverse sibling `conftest_pull` make the intended use obvious.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

conftest_testConftest testA
Read-onlyIdempotent

Evaluate configuration files (Kubernetes manifests, Terraform plans, Dockerfiles, Helm charts, or any YAML/JSON/HCL/TOML/INI) against Rego policies using conftest test. Returns per-file, per-namespace pass/fail/warn results so you can pinpoint exactly which policy rules fired. Requires conftest on PATH or CONFTEST_BINARY set; returns CONFTEST_NOT_FOUND otherwise. Provide config via files (disk paths) or inlineConfig (inline string). Provide policy via policy (disk path) or inlinePolicy (inline Rego source). Omit policy and inlinePolicy to use conftest's default ./policy directory. Policies are executed by conftest and can call OPA built-ins such as http.send.

ParametersJSON Schema
NameRequiredDescriptionDefault
dataNoPaths to directories from which additional data will be loaded for the Rego policies. Each path must be inside an allowed root.
filesNoFilesystem paths to configuration files to evaluate (YAML, JSON, HCL, Dockerfile, etc.). Each path must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Mutually exclusive with `inlineConfig`.
parserNoForce a specific parser for all input `files` via conftest's global `--parser` flag, overriding extension-based detection. Useful for files whose extension does not match their format (e.g. parse a `.tfstate` file as `json`). One of: cue, dockerfile, dotenv, edn, hcl1, hcl2, hocon, ignore, ini, json, jsonnet, nginx, properties, spdx, textproto, toml, vcl, xml, yaml. For `inlineConfig`, prefer `inlineConfigParser`.
policyNoPath to a directory or file containing Rego policies. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Mutually exclusive with `inlinePolicy`. Omit to let conftest use its default `./policy` directory.
combineNoCombine all configuration files into a single input document before evaluating. Useful when policies need to inspect relationships across multiple files.
namespaceNoRego namespace (package name) to test against. Defaults to `main`. Use `allNamespaces: true` to test all discovered namespaces instead.
failOnWarnNoReturn `passed: false` even when only warnings (no hard failures) are present.
inlineConfigNoInline configuration content to evaluate (e.g. a Kubernetes manifest as a YAML string). Mutually exclusive with `files`. Defaults to YAML format; set `inlineConfigParser` to override.
inlinePolicyNoInline Rego policy source. Written to a temporary directory and passed as `--policy`. The policy should declare `package main` (or match the `namespace` parameter). Mutually exclusive with `policy`.
allNamespacesNoTest policies found in all discovered namespaces. Overrides `namespace`.
inlineConfigParserNoParser to use for `inlineConfig`. One of: cue, dockerfile, dotenv, edn, hcl1, hcl2, hocon, ignore, ini, json, jsonnet, nginx, properties, spdx, textproto, toml, vcl, xml, yaml. Defaults to yaml. Ignored when `files` is used (conftest infers the parser from each file's extension, unless `parser` is set).

TDQS

A4.5/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover readOnly/openWorld/idempotent/destructive, and the description adds genuinely new behavioral facts: the external conftest binary requirement with the CONFTEST_NOT_FOUND failure mode, per-file/per-namespace result granularity, and the notable trait that policies can invoke OPA built-ins such as http.send, implying network side effects — which aligns with and extends the openWorldHint. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose is front-loaded in the first sentence, and every subsequent sentence covers a distinct topic: result format, dependency and failure mode, input options, defaults, and policy capabilities. At roughly 130 words it is dense but has no filler and nothing that merely repeats the schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex 11-parameter tool with no output schema, the description compensates well: it states the return shape (per-file, per-namespace pass/fail/warn), the external dependency, defaults, and the mutual-exclusion pairs echoed in the schema. Nothing an agent needs to call it correctly and interpret results is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all 11 parameters are already documented with types, mutual-exclusion constraints, and defaults. The description reinforces the two-axis mental model (config via files/inlineConfig, policy via policy/inlinePolicy) and the default policy directory, but adds little per-parameter meaning beyond what the schema provides. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a precise verb+resource: 'Evaluate configuration files ... against Rego policies using `conftest test`', enumerating the accepted formats (Kubernetes manifests, Terraform plans, Dockerfiles, Helm charts, etc.). This clearly differentiates the tool from the rego_* siblings, which operate on Rego source, and from conftest_verify/conftest_pull/conftest_push, which address other conftest workflows.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear operational context: two input axes (files vs inlineConfig, policy vs inlinePolicy), the mutually exclusive pairs, and the default `./policy` directory behavior when both policy options are omitted. However, it never names an alternative tool or states when not to use this tool, so an agent must infer differentiation from sibling names rather than explicit guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

conftest_verifyConftest verifyA
Read-onlyIdempotent

Run the test_* rules inside *_test.rego files within a conftest policy directory, verifying that the policies themselves are correct. Equivalent to opa test but using conftest's policy-loading machinery. Returns per-file pass/fail results, and NO_TESTS_FOUND when the directory holds no test rules. Requires conftest on PATH or CONFTEST_BINARY set; returns CONFTEST_NOT_FOUND otherwise.

ParametersJSON Schema
NameRequiredDescriptionDefault
dataNoPaths to data directories. Each must be inside an allowed root (OPA_MCP_ALLOWED_PATHS).
policyNoPath to the directory containing both the Rego policies and the `*_test.rego` test files. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Omit to use conftest's default `./policy` directory.
namespaceNoNamespace to verify. Defaults to `main`. Omit to verify all namespaces.

TDQS

A4/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description goes well beyond the read-only and idempotent annotations by explaining what the tool returns: per-file pass/fail results, NO_TESTS_FOUND when no test rules exist, and CONFTEST_NOT_FOUND when the binary is unavailable. This gives an agent concrete expectations about success, failure, and external dependency behavior without contradicting the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences and each one earns its place: first the core action, then the conceptual equivalence, then return/error behavior. It front-loades the purpose and avoids repetition or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With three optional parameters, 100% schema coverage, and no output schema, the description supplies the key operational details an agent needs: what results to expect, the no-tests case, and the required external dependency. The only meaningful gap is that it does not explicitly route away from similar sibling tools, which keeps it just short of fully complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already documents all three parameters with detailed descriptions, including allowed roots, defaults, and namespace behavior, so the schema coverage is 100%. The description adds only general context about the policy directory and test files, which aligns with the `policy` parameter but does not materially increase parameter-level understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Run') and names the exact resource (`test_*` rules in `*_test.rego` files) with the goal of verifying that conftest policies are correct. It also contrasts with `opa test` and conftest's loading machinery, but it does not explicitly distinguish itself from sibling tools like `conftest_test`, `rego_test`, or `rego_verify`.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description makes the domain clear — a conftest policy directory — and notes an equivalent behavior (`opa test`), which implies when the tool might be appropriate. It also states a prerequisite (`conftest` on PATH or `CONFTEST_BINARY` set), but gives no explicit when-to-use or when-not-to-use guidance against similarly named sibling tools, so the usage guidance is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

mcp_server_infoMCP server infoA
Read-onlyIdempotent

Return the name, version, and runtime details of this opa-mcp server instance. Use this when you need to confirm which version of opa-mcp is running, or to verify that the OPA, Regal, and Conftest binaries are reachable.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate readOnlyHint=true, destructiveHint=false, etc. The description adds value by specifying what the tool returns (name, version, runtime details) and that it checks binary reachability. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two concise sentences: first states purpose, second provides usage guidance. No wasted words, front-loaded with key information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers return values (name, version, runtime details, binary status) adequately. No output schema, but the description provides sufficient context for a simple info tool. Minor gap: 'runtime details' is vague, but overall complete enough.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has no parameters, and schema coverage is 100%. The description does not need to add parameter info. Baseline for 0 parameters is 4, and the description adds no unnecessary detail.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool returns name, version, and runtime details of the opa-mcp server. The verb 'Return' and resource 'opa-mcp server instance' are specific. Among siblings which are mostly OPA/Conftest/Rego manipulation tools, this is the only info tool about the server itself, so differentiation is clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states two use cases: confirming the version of opa-mcp and verifying reachability of OPA, Regal, and Conftest binaries. While it doesn't mention when not to use it, the context is clear and no alternatives are needed as the tool is unique among siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_bundle_buildBuild OPA bundleA
DestructiveIdempotent

Build a deployable bundle from policy / data paths using opa build. Output is a .tar.gz archive with optional inline signing. Supports optimization, custom revision strings, and the WASM target.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsYesPolicy / data paths to include. Each must be in an allowed root.
bundleNoLoad `paths` as bundle files or root directories (`--bundle`). Implied by `signingKey` and `verificationKey`; set it explicitly to rebuild an existing bundle without signing.
ignoreNoFile/directory name patterns to ignore during loading (`--ignore`), e.g. `[".*"]` to skip hidden files. These are name patterns, not filesystem paths.
outputYesOutput bundle path (typically `*.tar.gz`). Must be in an allowed root.
targetNoBuild target (default `rego`; `wasm` compiles to WebAssembly).
optimizeNoOptimization level (0 = none, 2 = aggressive).
revisionNoBundle revision string written to the manifest.
claimsFileNoPath to a claims file for inline signing.
signingAlgNoSigning algorithm (e.g. RS256).
signingKeyNoPath to a PEM private key for signing the built bundle (`--signing-key`). Implies `bundle: true`, which OPA requires for signing.
entrypointsNoEntrypoint refs (required when `target=wasm` or `optimize > 0`).
pruneUnusedNoExclude dependents of entrypoints that are not reachable from them (`--prune-unused`). Most useful alongside `entrypoints`.
capabilitiesNoPath to a capabilities JSON file.
v1CompatibleNoOpt in to OPA v1.0-compatible behaviors (`--v1-compatible`). Affects the built bundle's runtime semantics.
verificationKeyNoPath to a PEM public key (or HMAC secret file) used to re-verify an existing signed bundle during the build (`--verification-key`). Implies `bundle: true`, which OPA requires for verification.
verificationKeyIdNoKey ID for verification (`--verification-key-id`, OPA default `default`).

TDQS

A3.7/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=true, covering the safety profile. The description adds that the output is a .tar.gz archive and that signing is optional, but it does not disclose additional behavioral details such as overwriting existing outputs or the fact that signing implies bundle mode (though the schema covers the latter). No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences with no wasted words: purpose first, then output format, then supported features. The description is front-loaded and every sentence contributes useful information. The mention of `opa build` clarifies the underlying command without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (16 parameters, 2 required, no output schema), the description is a useful but high-level summary. It does not guide the agent on when to choose this tool over opa_bundle_sign/verify, nor does it highlight important constraints like entrypoints being required for wasm/optimize; the schema covers those details, but the description alone is not fully complete for a tool of this complexity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all 16 parameters. The description adds a high-level summary of key capabilities (optimization, revision strings, WASM target) that maps to parameters, but it does not provide meaningful new meaning beyond what the schema already states. Baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states a specific verb ('Build') and resource ('deployable bundle from policy / data paths') and adds concrete output details (.tar.gz, optional signing, WASM target). This distinguishes it from related siblings like opa_bundle_sign and opa_bundle_verify, which handle signing/verification rather than building.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage for building deployable bundles from policy/data paths, but it does not explicitly contrast this with related tools such as opa_bundle_sign, opa_bundle_verify, or rego_eval. There is no explicit when-to-use or when-not-to-use guidance, so the agent must infer the boundary from the description and sibling names.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_bundle_signSign OPA bundleA
DestructiveIdempotent

Sign a bundle directory or .tar.gz archive with opa sign. A directory is signed in place: .signatures.json is written into it and files are recorded as <directory name>/<file>, so the signed directory verifies wherever it is placed as long as its name is unchanged, with opa_bundle_verify or with opa build or opa run --bundle <name> from its parent. For an archive the signature is written beside it, into outputDir or the archive's own directory, and the archive is not modified; a signed archive comes from opa_bundle_build with signingKey. The key is a PEM private key (RSA or ECDSA); for HMAC algorithms pass a file holding the secret. Extra claims such as keyid and scope come from claimsFile. Returns the path written, the algorithm, and the number of files covered.

ParametersJSON Schema
NameRequiredDescriptionDefault
bundleYesPath to a bundle directory or `.tar.gz` archive. Must be inside an allowed root.
outputDirNoFor an archive, the directory that receives `.signatures.json`; defaults to the archive's own directory. Must exist and be inside an allowed root. Not accepted for a directory bundle, which is signed in place.
claimsFileNoPath to a JSON file of extra claims to sign, such as {"keyid": "...", "scope": "..."}. Must be inside an allowed root.
signingAlgNoSigning algorithm: RS256 (default), RS384, RS512, PS256, PS384, PS512, ES256, ES384, ES512, HS256, HS384, HS512.
signingKeyYesPath to the PEM private key (RSA or ECDSA), or for HMAC algorithms a file holding the secret. Must be inside an allowed root.

TDQS

A4.7/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the annotations (destructiveHint=true, idempotentHint=true), the description discloses the exact mutation semantics: a directory gets `.signatures.json` written into it in place, while an archive is not modified and receives a sidecar signature in `outputDir`. It also reveals the portability caveat — files are recorded as `<directory name>/<file>` so the directory must keep its name — which no annotation could convey. No contradiction with annotations; the destructive hint is consistent with the in-place write.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core action and then builds logically: directory behavior, archive behavior, key format, claims, return values. Each sentence carries unique operational information — no filler, no restatement of the title — and the length is justified by the tool's two distinct input modes.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description states the return values (path written, algorithm, file count) explicitly. It covers both input types, the mutation differences, key material requirements, claims injection, and names the sibling tools that complete the signing/verification workflow. Minor edge cases like overwriting an existing `.signatures.json` are not covered, but nothing essential to calling the tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so each parameter is already documented. The description adds interaction-level meaning: it explains that `bundle` may be a directory or archive, that `outputDir` applies only to archives, and that `signingKey` can be a PEM private key (RSA/ECDSA) or an HMAC secret file depending on `signingAlg`. It also ties `claimsFile` to concrete examples like `keyid` and `scope`, going beyond the schema's bare description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource — "Sign a bundle directory or `.tar.gz` archive with `opa sign`" — and immediately distinguishes the tool from its siblings by naming `opa_bundle_verify` (verification) and `opa_bundle_build` (build). It is not a tautology and leaves no ambiguity about what operation the tool performs.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear workflow context: directories are signed in place and verified with `opa_bundle_verify` or via `opa build`/`opa run --bundle`, while signed archives come from `opa_bundle_build` with `signingKey`. The archive-versus-directory distinction tells an agent which invocation form applies. It stops short of explicit when-not-to-use exclusions, but the alternatives are named and the selection conditions are inferable.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_bundle_verifyVerify OPA bundle signatureA
Read-onlyIdempotent

Verify the signature of a signed bundle directory or .tar.gz archive with the public key. OPA has no standalone verify command, so this runs opa build --verification-key into a private temp file that is discarded. A directory is verified by name from its parent, matching how opa_bundle_sign signs it. OPA reads the key, checks the JWT in .signatures.json, compares the scope claim, then checks every file: Rego files by digest before parsing, data files and .manifest by parsed value, so an unparseable data file fails before its digest is compared. Failures return INVALID_BUNDLE with details.reason set to one of signature_invalid, scope_mismatch, file_modified, file_added, file_missing, file_unparseable, unsigned, signatures_malformed, not_a_bundle, bundle_load_error, or unknown when the message is not recognised; the raw output is in details. A key or algorithm OPA cannot use returns INVALID_INPUT. Pass scope exactly as the bundle was signed with. With a single key OPA does not check verificationKeyId against the signature keyid claim. verified: true is returned only when OPA loaded the bundle with its signature intact.

ParametersJSON Schema
NameRequiredDescriptionDefault
scopeNoExpected `scope` claim in the signature. Pass exactly the value the bundle was signed with, and nothing if it was signed without one; the failure reason is scope_mismatch otherwise.
bundleYesPath to the signed bundle directory or `.tar.gz` archive. Must be inside an allowed root.
signingAlgNoSigning algorithm used when the bundle was signed (e.g. `RS256`, `PS256`, `ES256`, `HS256`). Defaults to `RS256`.
v0CompatibleNoLoad the bundle as Rego v0 (`--v0-compatible`). A policy written before Rego v1 otherwise fails to load, after the signature and digests have already been checked.
verificationKeyYesPath to the PEM file containing the RSA or ECDSA public key, or for HMAC algorithms a file holding the secret. Must be inside an allowed root.
verificationKeyIdNoName the key is registered under for OPA (`--verification-key-id`, default `default`). With a single key OPA verifies against it regardless of the signature keyid claim, so this rarely needs setting.

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate read-only, idempotent, non-destructive behavior, and the description goes well beyond that by disclosing the temp-file mechanism, the file-by-file verification order, digest-vs-parsed-value differences, failure reason enumerations, and the precise condition for returning `verified: true`. It also surfaces the `verificationKeyId` nuance.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is long but every sentence carries substantive behavioral or edge-case information for a complex tool. It is front-loaded with the core purpose and implementation, then proceeds into verification details and error conditions. Some schema repetition exists, such as the `scope` instruction, but overall it earns its length.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given there is no output schema, the description thoroughly documents return behavior: `INVALID_BUNDLE` with an enumerated `details.reason`, `INVALID_INPUT` for unusable keys or algorithms, and the exclusive condition for `verified: true`. It also covers failure ordering, v0 compatibility, directory verification convention, and key-ID behavior, making the tool self-sufficient for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so a baseline of 3 applies, but the description adds meaningful semantics: `scope` is emphasized as needing to match the signing value exactly, `v0Compatible` is tied to post-signature failure behavior, and `verificationKeyId` is explained as rarely needing to be set with a single key. This enriches the schema without being redundant.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The opening sentence names a specific verb and resource: 'Verify the signature of a signed bundle directory or `.tar.gz` archive with the public key.' It also clarifies the implementation mechanism and the matching relationship to `opa_bundle_sign`, which distinguishes it from general Rego verification siblings like `rego_verify` and `conftest_verify`.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives strong usage context: it explains that OPA has no standalone verify command, how the verification is performed, what inputs are required, and how `scope` must exactly match the signing value. It does not explicitly name alternative tools or say when not to use this tool, but the guidance is clear enough to invoke correctly.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_compile_queryCompile (partially evaluate) a query on OPAA
Read-onlyIdempotent

Send a query to the OPA server's /v1/compile endpoint for partial evaluation. Returns the residual query -- what remains after substituting in everything that's known.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoOptional partial input document.
queryYesRego query to compile, e.g. "data.rbac.allow == true".
unknownsNoRefs to treat as unknown (default: ["input"]).

TDQS

A3.8/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already provide readOnlyHint=true and idempotentHint=true. The description adds value by specifying the exact HTTP endpoint and explaining the concept of partial evaluation (substituting knowns). This provides behavioral context beyond annotations without contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences efficiently deliver the action and result. No extraneous text. The first sentence is front-loaded with the verb 'compile' and endpoint, making it immediately actionable.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the tool's core behavior and return value (residual query) without an output schema. It assumes familiarity with OPA concepts but is sufficient for an agent. Could add more on use cases or prerequisites, but is adequate for the complexity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with clear descriptions for all three parameters. The tool description reinforces the purpose of partial evaluation but does not add new parameter-specific details beyond the schema. Baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool sends a query to the OPA server's /v1/compile endpoint for partial evaluation and returns the residual query. This distinguishes it from evaluation tools like rego_eval or opa_query_decision, showing a specific verb and resource.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description does not explicitly state when to use this tool vs alternatives such as rego_eval or opa_query_decision. It only mentions partial evaluation but gives no guidance on scenarios or exclusions, leaving the agent to infer usage context from the tool name and siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_configOPA configurationA
Read-onlyIdempotent

Return the running OPA server configuration from GET /v1/config. OPA drops the credentials block but returns services.*.headers verbatim, which is the ordinary place to put an API key or a bearer token, so those values are redacted here and the header names kept.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

TDQS

A4.5/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses non-obvious behavior well beyond the annotations: OPA drops the `credentials` block, returns `services.*.headers` verbatim, and redacts header values while keeping header names. This is exactly the kind of behavioral context that helps an agent anticipate the returned data and security implications.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the core purpose and followed by a high-value behavioral caveat. Every clause earns its place; there is no redundant or filler content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

This is a simple zero-parameter read operation. The description states what is returned, where it comes from, and the important redaction behavior. Annotations already convey read-only and idempotent safety. No critical information is missing for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters and the schema coverage is 100%, so there are no parameter semantics for the description to clarify. Per the rubric, a zero-parameter tool gets a baseline of 4.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Return') and a precise resource ('the running OPA server configuration from `GET /v1/config`'). This clearly identifies what the tool does and separates it from sibling tools like opa_status or opa_health, which concern server health rather than configuration.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The use case is implied: if an agent needs the running OPA server configuration, this is the tool. However, the description does not explicitly state when to prefer this over alternatives or mention any exclusions, so guidance is present only by inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_delete_dataDelete a data document from OPAA
Destructive

Remove a document from OPA's data store at the given path. A path is read as dotted (users.alice) unless it contains a slash, in which case slash is the only separator (users/alice), so a key such as example.com is addressable as hosts/example.com. Pass segments instead when a key contains both. OPA responds with 204 No Content on success; if no document exists at the path, OPA returns 404 which is mapped to DATA_NOT_FOUND. Root-path deletion (/v1/data/ itself) is intentionally excluded -- supply at least one path segment.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathNoData path to delete, e.g. "users.alice" or "users/alice". Must be at least one segment deep.
segmentsNoPath as literal key segments, e.g. ["labels", "app.kubernetes.io/name"]. Use instead of `path` when a key contains a dot or a slash.

TDQS

A4.8/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the annotations (destructiveHint=true, idempotentHint=false), the description discloses the 204 success response, the 404-to-DATA_NOT_FOUND mapping, and the intentional root-path exclusion. These behaviors directly inform an agent about success, failure, and edge cases, which is exactly the kind of context annotations alone cannot provide.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is information-dense but every sentence earns its place: the core action, path syntax rules, fallback parameter guidance, and edge-case behavior are all stated with no filler. The most important context is front-loaded and the formatting is easy to scan.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter destructive operation with no output schema, the description is complete: it covers success codes, error mapping, path constraints, and the root-path edge case. The annotations already mark the destructive nature, and the description fills the remaining behavioral gaps an agent would need to safely invoke the tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Although the schema already covers 100% of parameters, the description adds crucial semantics: dotted vs slash-only path parsing, how to address keys containing dots or slashes, and when to switch from `path` to `segments`. This resolves ambiguous inputs that the schema descriptions only partially convey.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Remove') with a clear resource ('document from OPA's data store') and the path-based scope. It naturally distinguishes itself from sibling tools like opa_delete_policy by explicitly targeting the data store rather than policy.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear operational context: it explains when to use `path` vs `segments`, notes the root-path deletion exclusion, and requires at least one segment. It does not explicitly compare itself to alternative data-management tools like opa_patch_data or opa_put_data, but the conditional guidance is strong and the tool's purpose is unmistakable among siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_delete_policyDelete OPA policyA
Destructive

Delete a policy by ID from the running OPA server.

ParametersJSON Schema
NameRequiredDescriptionDefault
idYesPolicy ID to delete.

TDQS

A3.6/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, making the delete behavior clear. The description adds minimal extra context ('from the running OPA server') but does not disclose potential side effects, authentication needs, or constraints beyond the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single, front-loaded sentence with no wasted words. Every word is necessary and clear.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple one-parameter schema and no output schema, the description is mostly complete. However, it could mention error handling (e.g., policy not found) or that deletion is permanent, which would raise completeness to 5.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with 'Policy ID to delete.' in the parameter description. The tool description adds no further meaning, meeting the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action 'Delete', the resource 'a policy', and specificity 'by ID from the running OPA server'. This distinguishes it from sibling tools like opa_get_policy or opa_delete_data.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool vs alternatives (e.g., opa_put_policy to update) or prerequisites like ensuring the policy exists. The description only states the action without contextual usage advice.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_execBatch-evaluate OPA policy against input filesA
Read-onlyIdempotent

Evaluate a policy decision against one or more input files using opa exec --format=json. Unlike rego_eval (single input), opa exec processes every file independently and returns a per-file result -- ideal for CI pipelines that check many config files against a policy in one call. Supply bundle for bundle-based policies or dataPaths for raw policy files; these are mutually exclusive. Each file that fails evaluation appears in results with an error field rather than a result field. Set one of fail/failDefined/failNonEmpty to turn the call into a CI gate: the result then reports failed: true (instead of erroring) when the gate condition is met.

ParametersJSON Schema
NameRequiredDescriptionDefault
failNoCI gate: report `failed: true` when any decision is undefined or errors. Mutually exclusive with `failDefined` and `failNonEmpty`.
bundleNoPath to an OPA bundle directory or `.tar.gz` archive to load as the policy source. Mutually exclusive with `dataPaths`.
timeoutNoPer-exec evaluation timeout as a Go duration, e.g. `"30s"` or `"5m"`. Still bounded by the server subprocess timeout (OPA_MCP_TIMEOUT_MS).
decisionYesThe policy entrypoint to evaluate for each input, e.g. `"authz/allow"`. `opa exec` names a decision by slash-separated path with no `data.` prefix; the Rego reference forms (`data.authz.allow`, `authz.allow`) are accepted here and converted, because passing one straight through leaves every file undefined.
dataPathsNoPolicy and/or data file or directory paths, each loaded as an OPA bundle root (opa exec loads policy only via bundles). Mutually exclusive with `bundle`.
inputPathsYesOne or more JSON/YAML input file paths, or a directory containing input files. OPA evaluates each file independently. Every path must be inside an allowed root.
failDefinedNoCI gate: report `failed: true` when any decision is defined or errors. Use when a defined result means a violation. Mutually exclusive with `fail` and `failNonEmpty`.
failNonEmptyNoCI gate: report `failed: true` when any decision result is non-empty or errors. Mutually exclusive with `fail` and `failDefined`.
v1CompatibleNoOpt in to OPA v1.0-compatible behaviors (`--v1-compatible`).

TDQS

A4.8/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Although annotations already declare readOnlyHint=true and idempotentHint=true, the description adds substantial behavior beyond that: per-file independent evaluation, error fields instead of result fields for failing files, CI-gate behavior reporting failed: true instead of erroring, and the decision-name normalization that prevents undefined results. No contradiction with annotations exists.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is dense but every sentence earns its place: the core operation and tool name are front-loaded, the sibling comparison follows immediately, then per-file behavior, CI gates, and mutual exclusions are covered. The length is justified by the tool's complexity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 9-parameter tool with no output schema, the description covers invocation details, mutual exclusions, gate semantics, timeout bounds, and decision-name conversion. It could go slightly further by sketching the successful result envelope shape, but it adequately supports correct selection and invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and each parameter already has a solid description, so the baseline is 3. The description adds aggregate meaning by clarifying the interaction between fail/failDefined/failNonEmpty and the overall CI-gate result, plus the semantic difference between bundle and dataPaths. It adds value beyond the schema without replacing it.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Evaluate a policy decision against one or more input files using opa exec --format=json.' It immediately distinguishes itself from the sibling tool rego_eval by noting the single-input vs. batch-input difference, so an agent can tell them apart without inspecting schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly names rego_eval as the alternative for single inputs and says opa exec is 'ideal for CI pipelines that check many config files against a policy in one call.' It also explains when to use the fail gates and that bundle and dataPaths are mutually exclusive, giving clear selection and invocation guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_get_dataRead data from OPAA
Read-onlyIdempotent

Read a path from OPA's data hierarchy. A path is read as dotted (users.alice) unless it contains a slash, in which case slash is the only separator (users/alice), so a key such as example.com is addressable as hosts/example.com. Pass segments instead when a key contains both.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathNoData path under `data.`, e.g. "users" or "users/alice".
segmentsNoPath as literal key segments, e.g. ["labels", "app.kubernetes.io/name"]. Use instead of `path` when a key contains a dot or a slash.

TDQS

A4.3/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral detail about path interpretation: dotted notation versus slash-only separator, and how a key containing a dot can still be addressed. This goes beyond what annotations and schema alone provide.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three tightly written sentences with no filler. The core action is front-loaded, and the necessary path-format nuances are packed efficiently into the remaining sentences.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a low-complexity read tool with strong annotations, the description is nearly complete. It covers the trickiest part: path formatting and segments selection. A minor gap is that it does not state what happens when neither `path` nor `segments` is provided, even though the schema allows zero required parameters.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema description coverage, the baseline is 3, but the description substantially enriches parameter understanding. It clarifies the dotted-path rule, the slash-only fallback, the `example.com` addressing case, and the exact condition for using `segments` instead of `path`. This resolves real ambiguity in how to invoke the tool.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with 'Read a path from OPA's data hierarchy,' which names a specific verb, resource, and scope. This clearly differentiates it from siblings like opa_get_policy (policies) and opa_query_decision (decision evaluation) by targeting the data hierarchy specifically.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives strong internal guidance on when to use `path` vs `segments`, but it never names alternative tools or states when this tool should be preferred over opa_get_policy or opa_query_decision. Tool-selection context is implied by 'data hierarchy' but not made explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_get_policyGet OPA policy by IDA
Read-onlyIdempotent

Fetch a single policy by ID from the running OPA server. Returns the Rego source; the parsed AST is omitted unless asked for, since it is roughly forty times the size of the source it came from. Use rego_parse_ast on the source when an AST is what's wanted.

ParametersJSON Schema
NameRequiredDescriptionDefault
idYesPolicy ID, e.g. "rbac" or "policies/auth/main".
includeAstNoInclude OPA's parsed AST alongside the source. Off by default.

TDQS

A4.7/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/idempotent/non-destructive, so the bar for added context is lower. The description adds real behavior: the tool returns Rego source, omits the AST by default, explains the size tradeoff, and notes the includeAst alternative. No contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, all substantive, with the main purpose in the first clause. No filler or duplication of schema fields.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-required-parameter read tool, the description covers what the caller gets (Rego source), the optional behavior (includeAst), and the alternative for AST. Annotations cover safety and idempotency, and schema covers parameters, so nothing essential is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so parameters are fully documented; the description adds little beyond what the schema already provides. The mention that AST is omitted 'unless asked for' aligns with includeAst's schema description, so no additional compensation is needed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description opens with a specific verb+resource: 'Fetch a single policy by ID from the running OPA server.' It clearly scopes to one policy, distinguishes from list/put/delete siblings, and differentiates from rego_parse_ast by stating this returns Rego source and AST is optional.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states that the AST is omitted unless asked and directs the agent to use `rego_parse_ast` when an AST is wanted, giving a concrete when-not. It also implies the primary use case—getting the Rego source for one policy—without ambiguity.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_healthOPA health checkA
Read-onlyIdempotent

Hit the OPA /health endpoint. A server that answers reports { healthy: true } on 200 and { healthy: false } with OPA's own reason otherwise, so an unactivated bundle is a health result rather than a tool error. OPA_UNREACHABLE means the server could not be reached at all. Supports bundles and plugins query flags to require those subsystems to also be healthy.

ParametersJSON Schema
NameRequiredDescriptionDefault
bundlesNoRequire bundle plugin to be healthy as well.
pluginsNoRequire all plugins to be healthy.

TDQS

A4.3/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safe-read profile (readOnlyHint, idempotentHint, non-destructive), so the description's job was to add behavioral depth beyond that, and it delivers: the exact endpoint, 200-vs-otherwise result semantics, the key gotcha that an unactivated bundle yields { healthy: false } rather than a tool error, and the OPA_UNREACHABLE failure mode. These are precisely the interpretation cues an agent needs and cannot derive from annotations or the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, roughly 70 words, with no filler. The endpoint is front-loaded, followed by result interpretation, the unreachable edge case, and finally the flags — a logical order where every sentence earns its place. Nothing is redundant with the schema or annotations.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-required-param, read-only health check with no output schema, the description is fully sufficient: it names the endpoint, defines both success and failure result shapes, covers the edge cases (unactivated bundle, unreachable server), and documents both optional flags. There is nothing an agent needs in order to call this tool correctly that is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% — both bundles and plugins already carry adequate descriptions. The description's phrase 'query flags to require those subsystems to also be healthy' adds a small amount of meaning by tying the booleans to the subsystem-health concept, which aligns with and slightly reinforces the schema. Since the schema does the heavy lifting, the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Names the specific resource (`/health` endpoint) with a clear verb ('Hit'), and then defines the expected response semantics. This makes the tool immediately distinguishable from the many siblings in the namespace, especially opa_status and opa_config, without needing to open their schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description conveys useful context about when to use the tool — checking whether the OPA server (and optionally its subsystems) is healthy — and clarifies that an unactivated bundle appears as a health result rather than a tool error, which affects result interpretation. However, it never explicitly names alternatives or gives when-to-use / when-not-to-use conditions, so routing among overlapping siblings like opa_status and opa_config is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_list_policiesList OPA policiesA
Read-onlyIdempotent

List policies registered on the running OPA server. Returns the policy IDs and a count. Set includeSource for the Rego text of every policy, or includeAst for the parsed AST of every policy; both are off by default because either one pushes a list of any real size past the response cap.

ParametersJSON Schema
NameRequiredDescriptionDefault
includeAstNoInclude each policy's parsed AST. Off by default; it is roughly forty times the size of the source and will exceed the response cap on all but the smallest servers.
includeSourceNoInclude each policy's Rego source. Off by default: fetch one policy with `opa_get_policy` rather than every policy at once.

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile comprehensively (readOnlyHint=true, idempotentHint=true, openWorldHint=true, destructiveHint=false), so the bar for the description is lower. The description adds genuine behavioral value beyond annotations by disclosing the response-cap behavior: enabling either include flag can cause list responses to exceed the cap. This is exactly the kind of operational trait an agent needs to anticipate failure modes.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, zero filler. The first sentence front-loads the action and return value; the second handles the optional parameters and the reason for the defaults. Every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple listing tool with 0 required parameters, rich annotations, and no output schema, the description is nearly complete: it states the return value at a useful level ('policy IDs and a count') and explains both flags. It could marginally improve by describing the response envelope or ordering, but nothing an agent needs to invoke it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with unusually rich per-parameter descriptions (size ratios, response-cap warnings, alternative-tool routing), which sets the baseline at 3. The description adds meaning on top by distinguishing the two flags at a semantic level — 'Rego text' vs 'parsed AST' — and stating the shared default-off behavior and its rationale, which is not fully redundant with the schema text.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource — 'List policies registered on the running OPA server' — and goes beyond that to specify the return value ('policy IDs and a count'). The phrase 'running OPA server' clearly differentiates this from the many rego_* sibling tools that operate on static policy files, and from opa_get_policy/opa_put_policy/opa_delete_policy which target individual policies.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context: use this to enumerate registered policies, and the optional include flags are discouraged by default because they 'push a list of any real size past the response cap.' This effectively tells an agent when NOT to set the flags. It does not explicitly name opa_get_policy as the alternative for fetching a single policy's source in the description body — that routing lives in the schema — so it stops just short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_patch_dataPatch data on OPAA
Destructive

Apply a JSON Patch (RFC 6902) to the data document. Each operation is { op, path, value? }. Omit both path and segments to patch the root of the data hierarchy, which is how a whole new top-level document is added.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathNoData path the patch is applied to.
segmentsNoPath as literal key segments, e.g. ["labels", "app.kubernetes.io/name"]. Use instead of `path` when a key contains a dot or a slash.
operationsYesArray of JSON Patch operations.

TDQS

A3.7/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate this is a destructive, non-idempotent write operation. The description adds useful behavioral context by explaining the operation format and that omitting path and segments patches the root to add a new top-level document. It does not go into further side effects, but the annotation covers the main destructive risk.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences with no wasted words. It front-loads the core action, then gives the operation shape, then handles the important root-patch special case. Each sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a three-parameter tool with annotations covering the destructive nature and a schema covering all parameters, the description provides the remaining key context: how operations are structured and how to target the root. There is no output schema, but return-value details are not critical for invoking this tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds value beyond the schema by clarifying the JSON Patch operation shape and the special root-patching behavior when both path and segments are omitted. This is meaningful parameter-level guidance an agent would not get from the schema alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly identifies the action: applying an RFC 6902 JSON Patch to the OPA data document. It names a specific verb and resource and is distinct from sibling tools like opa_put_data and opa_delete_data, though it does not explicitly differentiate itself from them in the description.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when this tool is useful by defining it as the JSON Patch mechanism for data, and it gives a concrete usage tip about omitting path/segments to patch the root. However, it does not explicitly state when to use this tool instead of alternatives such as opa_put_data or opa_delete_data.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_put_dataWrite data to OPAA
DestructiveIdempotent

Write or replace a value at the given data path. Body is sent as JSON. A path is read as dotted (users.alice) unless it contains a slash, in which case slash is the only separator (users/alice), so a key such as example.com is addressable as hosts/example.com. Pass segments instead when a key contains both.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathNoData path to write to.
valueNoJSON value to store at this path.
segmentsNoPath as literal key segments, e.g. ["labels", "app.kubernetes.io/name"]. Use instead of `path` when a key contains a dot or a slash.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructive and idempotent hints; the description adds non-obvious runtime behavior: the body is JSON, path separator parsing switches between dots and slashes, and dot-containing keys can be addressed via slash-separated paths. This is meaningful context beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Every sentence earns its place: purpose, body format, separator rule, and segments fallback. The most important verb-first statement is front-loaded and the paragraph is dense without padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tricky path-encoding behavior is fully explained, and annotations cover the destructive/idempotent safety profile. There is no output schema and no response description, but for a write operation the essential calling requirements are covered.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3, but the description elevates it by explaining how `path` is parsed, why `hosts/example.com` works, and when `segments` is the right parameter. It adds practical meaning not fully present in the schema's field descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action ('Write or replace a value') on a specific resource (OPA data path), which clearly distinguishes it from siblings like opa_patch_data and opa_delete_data. The 'replace' wording communicates full overwrite rather than merge or delete.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives useful in-tool guidance for choosing path versus segments, but it never addresses when to use opa_put_data instead of opa_patch_data or opa_delete_data. Tool-vs-alternative selection is therefore left mostly implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_put_policyUpload or replace OPA policyA
DestructiveIdempotent

Upload a Rego policy under the given ID. Replaces any existing policy with that ID. The policy is uploaded as raw text/plain -- OPA parses it on the server side.

ParametersJSON Schema
NameRequiredDescriptionDefault
idYesPolicy ID to create or replace.
sourceYesRego source.

TDQS

A3.6/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate destructive and idempotent behavior. The description adds that the policy is uploaded as raw text/plain and parsed server-side, and that it replaces any existing policy with that ID, providing useful behavioral context beyond annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, no redundant information. It is concise and front-loaded with the key action. Could potentially be structured as a brief paragraph but still efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with no output schema, the description covers core behavior (replace, raw text). However, it does not mention return values or error conditions, which would be helpful for completeness given the tool's destructive nature.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema descriptions already define 'id' and 'source' adequately. The description adds that the source is raw text/plain, which is helpful but not extensive. With 100% schema coverage, the description does not significantly enhance parameter understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Upload' and resource 'Rego policy' with a given ID. It distinguishes from sibling tools like opa_get_policy and opa_delete_policy by specifying the upload/replace action.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives such as opa_put_data or opa_bundle_build. There is no mention of prerequisites or context where this tool is preferred.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_query_decisionQuery OPA decisionA
Read-onlyIdempotent

Evaluate a decision against the running OPA server. POSTs to the data path with {input} and returns whatever the rule produces. Use this to ask the server "given this input, what does data.X.allow say?"

ParametersJSON Schema
NameRequiredDescriptionDefault
pathNoDecision path under `data.`, e.g. "rbac/allow" or "rbac.allow".
inputNoInput document to evaluate against.
explainNoInclude a trace at the requested level.
metricsNoInclude metrics in the response.
segmentsNoPath as literal key segments, e.g. ["labels", "app.kubernetes.io/name"]. Use instead of `path` when a key contains a dot or a slash.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark this as read-only, idempotent, and non-destructive. The description adds valuable behavioral context by specifying the POST method, the data-path endpoint, and that the response is 'whatever the rule produces'. It does not detail error or undefined-rule behavior, but the annotations lower the burden.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no wasted words. It front-loads the action and endpoint, then gives a concrete example in the second sentence.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Without an output schema, the phrase 'returns whatever the rule produces' gives useful response expectations, and annotations cover the safety profile. The need to provide a path or segments is implied but not explicit, which is a minor gap given the schema hints.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already documents all five parameters with clear descriptions. The description reinforces the meaning of `path` and `input` through the data.X.allow example, but it does not add significant meaning beyond the schema, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Evaluate'), a specific resource ('the running OPA server'), and the mechanism ('POSTs to the data path'). The quoted example, 'given this input, what does data.X.allow say?', clearly differentiates this from local evaluation siblings like rego_eval.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives clear context for when to use this tool: querying a running OPA server with an input document. It implicitly distinguishes from local rego evaluation tools, but it does not explicitly name alternatives or state when not to use this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

opa_statusOPA statusA
Read-onlyIdempotent

Return the running OPA server configuration via GET /v1/config. Returns the same underlying document as opa_config but presented under a status key as a convenience for agents that want to check "what is running" rather than "what was the server configured with". The response includes bundle settings, decision-log settings, and plugin configuration as OPA reported them at startup. Service header values are redacted, since OPA returns them verbatim and a header is the ordinary place to put an API key.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

TDQS

A4.9/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the readOnlyHint/idempotentHint annotations, the description discloses meaningful behavioral details: the response reflects startup-reported configuration, includes bundle/decision-log/plugin settings, and service header values are redacted because they may contain API keys. This adds genuine transparency beyond what structured annotations already convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, each earning its place: the first states the action and endpoint, the second clarifies the difference from a sibling tool, and the third covers response contents and a security-relevant redaction. The description is front-loaded and compact with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Although there is no output schema, the description compensates by enumerating response categories, clarifying the relationship to opa_config, and warning about redacted header values. For a zero-parameter read-only status tool, this is sufficient context for an agent to invoke it correctly and interpret its result.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There are zero parameters, so schema coverage is complete by definition and the description need not explain parameters. It still adds useful context about what the returned configuration document contains and the redaction policy, which is more than the empty schema provides. Baseline 4 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource ('Return the running OPA server configuration via GET /v1/config') and precisely distinguishes this tool from its sibling opa_config by noting the 'status' key presentation and the intent to check 'what is running' vs 'what was configured'. This gives an agent a clear, unambiguous purpose.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly names the alternative tool opa_config and states the selection criterion: use this when the agent wants 'what is running' rather than 'what was the server configured with'. This is direct routing guidance with no ambiguity about when to prefer this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_benchBenchmark Rego queryA
Read-onlyIdempotent

Benchmark a Rego query against a policy + input with opa bench. Returns statistical timing data: iterations, ns/op, and allocation counts. Use this to spot slow rules.

ParametersJSON Schema
NameRequiredDescriptionDefault
countNoNumber of times to repeat the benchmark (`--count N`). Defaults to OPA's built-in default of one. Every repetition is returned in `runs`; the top-level figures come from the fastest of them.
inputNoInline input document.
pathsNoPolicy / data paths to load. Each must be in an allowed root.
queryYesRego query to benchmark.
inputPathNoPath to a JSON input file.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish that the tool is read-only, non-destructive, and idempotent. The description adds useful behavioral information beyond that: it invokes `opa bench` and returns timing statistics rather than ordinary evaluation results. This helps the agent predict observable behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences with no filler: the first states the action, the second enumerates the return data, and the third gives the use case. Every sentence earns its place and the content is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description's explicit mention of iterations, ns/op, and allocation counts is valuable. The schema fully documents all five parameters. The description could add explicit comparisons to profiling-related siblings, but it is otherwise complete enough for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and parameter descriptions are already detailed, including count semantics, paths, and inputPath. The tool description adds only the high-level 'policy + input' framing, so it does not need to compensate for schema gaps.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb ('Benchmark'), a specific resource ('a Rego query against a policy + input'), and the implementation (`opa bench`). The output statistics are also listed, making it easy to distinguish this from sibling tools like rego_eval or rego_test.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The final sentence explicitly tells the agent when to use this tool: 'Use this to spot slow rules.' It does not explicitly state when to prefer alternatives such as rego_eval_with_profile, but the benchmark framing provides clear selection context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_capabilitiesOPA capabilitiesA
Read-onlyIdempotent

Return OPA capabilities -- the available builtins, future keywords, features, and WASM ABI versions. With current: true, returns the running OPA's capabilities. With version: "v1.19.0", returns those of a specific version. With neither, lists available named versions. By default (names_only: true), returns only builtin names and count to stay within response size limits; pass names_only: false for full type signatures and documentation.

ParametersJSON Schema
NameRequiredDescriptionDefault
currentNoPrint the capabilities of the currently installed OPA. Mutually exclusive with `version`.
versionNoA specific OPA capabilities version (e.g. "v1.19.0"). When neither flag is set, lists available versions.
names_onlyNoWhen true (default), return only builtin names, count, future keywords, and features. The full spec payload routinely exceeds client response size limits. Set to false to retrieve complete type signatures, documentation, and metadata for every builtin.

TDQS

A4.4/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses important behavioral traits beyond the annotations: it explains the response size limit rationale for names_only default, what data is returned in each mode, and the trade-off of setting names_only to false. This adds substantial context the annotations alone do not provide.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise (3 sentences) and front-loaded with the core purpose in the first sentence. Each subsequent sentence earns its place by describing parameter modes and default behavior. No filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given three optional parameters and no output schema, the description provides enough context: it explains the return content, the version-specific behavior, and the names_only trade-off. It does not detail the output format, but this is not critical given the clarity of the content description.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema covers all three parameters with detailed descriptions (mutual exclusivity, default behavior, response size rationale). The description repeats much of this information without adding new meaning, so it neither enhances nor detracts from the schema's coverage. Baseline 3 is appropriate since schema coverage is 100%.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Return OPA capabilities' followed by a clear breakdown of contents (builtins, future keywords, features, WASM ABI versions). This clearly distinguishes it from sibling Rego/OPA tools, which focus on formatting, parsing, testing, or policy operations.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives explicit conditional usage for each parameter combination: 'With current: true...', 'With version...', 'With neither...'. It also explains the names_only default and how to override it. While it does not explicitly name alternatives or exclusions, the parameter-driven guidance is clear and actionable.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_checkCheck RegoA
Read-onlyIdempotent

Type-check Rego with opa check. Returns { valid: true, errors: [] } on success, or a list of structured diagnostics with file/line locations on failure. Provide either source for inline checking or paths for file/directory checking.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsNoFilesystem paths to check. Each path must be inside an allowed root (OPA_MCP_ALLOWED_PATHS).
bundleNoLoad `paths` as bundle files or root directories (`--bundle`). Only valid with `paths`, not inline `source`.
sourceNoInline Rego source. Mutually exclusive with `paths`.
strictNoEnable strict mode -- fail on unused vars, deprecated builtins, etc.
maxErrorsNoMaximum number of errors to collect before `opa check` aborts compilation (`--max-errors`, OPA default 10). Raise it to surface more diagnostics from a badly broken policy in a single pass.
schemaDirNoSchema directory for input/data validation.
capabilitiesNoPath to a capabilities JSON file restricting allowed builtins.

TDQS

A4.5/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare readOnlyHint, destructiveHint, and idempotentHint. The description adds that the tool runs 'opa check' and returns structured diagnostics with locations, providing behavioral context beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the verb and resource. Every sentence adds essential information without waste.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the return format (valid/errors with diagnostics) and explains the two input modes. No output schema is provided, but the description adequately describes the output.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents each parameter. The description adds value by explaining the mutual exclusivity of source/paths and the purpose of maxErrors, going beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description specifies the verb 'type-check' and the resource 'Rego', explicitly invoking 'opa check'. It distinguishes from siblings like rego_lint and rego_test by focusing on type-checking.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description clearly states the two mutually exclusive usage modes: inline source or file/directory paths. It does not explicitly list when not to use this tool vs alternatives, but the context is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_check_schemaCheck Rego against a JSON SchemaA
Read-onlyIdempotent

Validate that a Rego policy's input.* field references are consistent with a JSON Schema using opa check --schema. Every field the policy reads from input must exist in the schema; mismatches surface as rego_type_error diagnostics with file/line locations. Returns { valid: true, errors: [] } when all references match the schema, or { valid: false, errors: [...] } with structured diagnostics when they do not. Accepts the schema inline (pass the schema output of rego_infer_input_schema directly as inlineSchema) or as a path to an existing JSON Schema file on disk (schemaPath). Provide source for inline Rego or paths for file/directory checking.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsNoFilesystem paths to policy files or directories to validate. Each path must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Mutually exclusive with `source`.
sourceNoInline Rego source to validate against the schema. Mutually exclusive with `paths`.
strictNoEnable strict mode -- also fail on unused variables, deprecated builtins, and other non-fatal issues in addition to schema violations.
schemaPathNoPath to a JSON Schema file on disk to use for `input` validation. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Mutually exclusive with `inlineSchema`.
inlineSchemaNoJSON Schema (draft-07) object describing the expected shape of the `input` document. Mutually exclusive with `schemaPath`. Accepts the `schema` field from `rego_infer_input_schema` output directly.

TDQS

A4.7/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, openWorldHint=false. The description adds valuable behavioral context: it returns structured diagnostics, uses `opa check --schema`, and explains how mismatches are reported. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is 120 words, front-loaded with purpose, then behavior, return format, and parameters. Every sentence adds value with no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 5 parameters (some nested), no output schema, and complexity of mutex constraints, the description covers all necessary details: purpose, return format, schema sources, path restrictions, and strict mode. No gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. The description adds meaning by explaining the mutual exclusivity of source/paths and inlineSchema/schemaPath, and that schemaPath must be within allowed roots. This goes beyond the schema's own descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses specific verb 'Validate' and resource 'Rego policy's input.* field references against a JSON Schema'. It clearly distinguishes from siblings by specifying the use of `opa check --schema`, which is unique among rego_* tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains when to use the tool (for schema validation) and provides details on how to provide the schema (inline or path). However, it does not explicitly state when not to use it (e.g., for general syntax checks), though the context is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_compile_queryPartially evaluate a Rego queryA
Read-onlyIdempotent

Run partial evaluation on a query -- substitute known values and return the residual policy. Defaults unknowns to ["input"] (treat input as unknown), so the residual encodes "given input X, this is what would have to be true." Use this for offline policy slicing or pre-computing decision sets.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInline input document.
pathsNoPolicy / data file or directory paths. Each must be inside an allowed root.
queryYesRego query to evaluate, e.g. "data.example.allow".
sourceNoInline Rego policy source. Mutually exclusive with `paths`.
partialNoRun partial evaluation rather than full evaluation.
unknownsNoRefs to treat as unknown during partial evaluation.
inputPathNoPath to a JSON input file. Mutually exclusive with `input`.
strictBuiltinErrorsNoTreat builtin errors as fatal instead of returning undefined.

TDQS

A4.1/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations indicate readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds context by explaining the default for 'unknowns' and the meaning of the residual policy, which is not covered by annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the action of partial evaluation, and no unnecessary words. The structure is clear and efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the complexity (8 parameters, no output schema), the description provides a high-level understanding but does not mention what the output format is (e.g., JSON or Rego string). It is adequate but could be more complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the description does not need to add much. It does highlight the default for 'unknowns', but other parameters are not elaborated beyond their schema descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool performs partial evaluation on a Rego query, substituting known values and returning a residual policy. It distinguishes from siblings like rego_eval by specifying the partial evaluation nature.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states use cases: 'offline policy slicing or pre-computing decision sets.' It does not mention when not to use it, but the context is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_coverage_gapsRego test coverage gapsA
Read-onlyIdempotent

Run opa test --coverage and return a per-file breakdown of uncovered line ranges. Identifies which rules or branches are not yet exercised by tests. Files are sorted by coverage ascending so the worst-covered files appear first. Use threshold to limit the report to files below a target coverage percentage.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsYesTest directories or files. opa test looks for *_test.rego siblings of source files.
thresholdNoReport only files below this coverage percentage (0-100). When omitted, all files with uncovered ranges are reported.
runPatternNoRun only tests whose names match this regex.

TDQS

A4.3/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare readOnly, destructive false, idempotent. Description adds behavioral context: runs opa test, sorts output, threshold usage. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

3-4 sentences, front-loaded with key action, no unnecessary words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers purpose, sorting, threshold. Omitted runPattern parameter. No output schema, so description could be more specific about output structure. Adequate for most use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers all 3 params with descriptions. Description repeats threshold's purpose but doesn't add new meaning beyond schema. runPattern not mentioned in description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Clear verb+resource+scope: runs opa test --coverage, returns per-file breakdown of uncovered line ranges, sorts by coverage ascending. Distinguishes from sibling rego_test by focusing on gaps, not test pass/fail.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

States purpose (coverage gap analysis) and mentions threshold filtering but does not explicitly compare to siblings like rego_test or rego_eval_with_coverage. Agent can infer use case but no direct when-not guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_depsRego dependency analysisA
Read-onlyIdempotent

Static dependency analysis for a Rego reference. Given a target ref like "data.example.allow", returns the base document references (input/data leaves) and virtual document references (rules) it depends on, transitively.

ParametersJSON Schema
NameRequiredDescriptionDefault
refYesReference to compute dependencies for, e.g. "data.example.allow".
pathsYesPolicy / data paths to load before computing dependencies. Each must be inside an allowed root (OPA_MCP_ALLOWED_PATHS).

TDQS

A4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description's mention of 'static analysis' adds context but does not disclose additional behavioral traits like performance or side effects beyond what annotations provide.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, well-structured sentence that front-loads the purpose and key details. No redundant information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite no output schema, the description explains what the tool returns (base and virtual document references, transitively). It covers purpose, parameters, and output sufficiently for a static analysis tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, baseline 3. The description adds meaning by explaining the ref format (e.g., 'data.example.allow') and the paths constraint (must be inside allowed root), which adds value beyond the schema descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool performs static dependency analysis for a Rego reference, specifying the target ref format and what it returns (base and virtual document references). This distinguishes it from sibling tools like rego_check or rego_eval.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage for dependency analysis but does not explicitly state when to use this tool versus alternatives like rego_eval or rego_explain_decision. No when-not or alternative guidance is provided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_describe_policyDescribe Rego policyA
Read-onlyIdempotent

Parse a Rego policy and return a structured summary: package, imports, and rules. Each rule reports clauseCount (how many definitions share the name), isDefault (true if any clause is a default), hasArgs, bodyLength (total body expressions across all clauses), and inline annotations. Useful as the first step in any "what does this policy do" workflow.

ParametersJSON Schema
NameRequiredDescriptionDefault
sourceYesRego source to describe.

TDQS

A4.1/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare readOnlyHint, idempotentHint, and destructiveHint, which the description aligns with by stating it 'parse[s] a Rego policy and return[s] a structured summary.' The description adds useful behavioral detail beyond annotations, such as listing specific output fields (clauseCount, isDefault, etc.).

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise, consisting of three sentences that flow logically: what the tool does, details about what it returns, and a use case. Each sentence adds value without unnecessary verbosity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite having no output schema, the description adequately describes the return value (package, imports, rules, and rule details) and covers the tool's functionality for a single-input, simple tool. It is complete enough for an agent to understand the tool's purpose and output.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 100% coverage for the single parameter 'source' with description 'Rego source to describe.' The tool description does not add significant new meaning, as the schema already explains the parameter adequately. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool parses a Rego policy and returns a structured summary including package, imports, rules, and detailed rule attributes. It distinguishes itself from sibling tools like rego_eval, rego_check, and rego_inspect by focusing purely on structural description.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly suggests using this tool as 'the first step in any 'what does this policy do' workflow,' providing clear context for when to use it. It does not explicitly mention when not to use it or contrast with alternatives, but the guidance is sufficient.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_evalEvaluate Rego queryB
Read-onlyIdempotent

Evaluate a Rego query against a policy and an input document using opa eval. Returns the standard {result: [...]} shape. The bread-and-butter authoring tool.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInline input document.
pathsNoPolicy / data file or directory paths. Each must be inside an allowed root.
queryYesRego query to evaluate, e.g. "data.example.allow".
sourceNoInline Rego policy source. Mutually exclusive with `paths`.
partialNoRun partial evaluation rather than full evaluation.
unknownsNoRefs to treat as unknown during partial evaluation.
inputPathNoPath to a JSON input file. Mutually exclusive with `input`.
strictBuiltinErrorsNoTreat builtin errors as fatal instead of returning undefined.

TDQS

B3.4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds the output shape 'standard {result: [...]} shape', which is useful but goes no further. No additional behavioral traits like auth or rate limits are mentioned.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the core purpose, followed by essential output shape and positioning. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given schema coverage and annotations, the description is mostly complete. It mentions the output shape and positions the tool as central. However, it could briefly note that many parameters like 'source' and 'paths' are mutually exclusive, though those details are in the schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so per guidelines baseline is 3. The description does not add any meaning beyond what the schema already provides for parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly identifies the tool as evaluating a Rego query with specific resources (policy, input document) and output shape. It uses the verb 'Evaluate' and the resource 'Rego query against a policy and an input document'. However, it does not explicitly differentiate from siblings like rego_eval_with_coverage, though the term 'bread-and-butter' implies primacy.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit guidance on when to use this tool versus alternatives (e.g., rego_eval_with_coverage for coverage tracking). The phrase 'bread-and-butter' hints at default usage but lacks explicit context or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_eval_with_coverageEvaluate Rego with coverageA
Read-onlyIdempotent

Evaluate with --coverage and return per-line coverage data. Useful for verifying that tests actually exercise the rules they're meant to.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInline input document.
pathsNoPolicy / data file or directory paths. Each must be inside an allowed root.
queryYesRego query to evaluate, e.g. "data.example.allow".
sourceNoInline Rego policy source. Mutually exclusive with `paths`.
partialNoRun partial evaluation rather than full evaluation.
unknownsNoRefs to treat as unknown during partial evaluation.
inputPathNoPath to a JSON input file. Mutually exclusive with `input`.
strictBuiltinErrorsNoTreat builtin errors as fatal instead of returning undefined.

TDQS

A4.1/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate readOnly=true, destructive=false, idempotent=true. The description adds that it returns per-line coverage data, which is useful behavioral detail. No contradictions. It could mention that evaluation is side-effect-free, but annotations cover that.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences: first states the action and output, second gives usage context. No redundant words, front-loaded with key information. Highly concise.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 8 parameters and no output schema, the description is brief. It does not explain the output format (e.g., structure of coverage data), error handling, or performance implications. While the schema covers parameters, additional context about return values would improve completeness.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description does not elaborate on parameters beyond what the schema already provides (e.g., mutual exclusivity of source/paths, input/inputPath). No added value for parameter semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool evaluates with --coverage and returns per-line coverage data. This distinguishes it from siblings like rego_eval, rego_eval_with_explain, rego_eval_with_profile, and rego_coverage_gaps by specifying the exact feature (coverage).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description says 'Useful for verifying that tests actually exercise the rules they're meant to,' which gives clear context for when to use it (for test coverage). However, it lacks explicit guidance on when not to use it or how it compares to alternatives like rego_test or rego_coverage_gaps.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_eval_with_explainEvaluate Rego with execution traceA
Read-onlyIdempotent

Evaluate with --explain=full and return a structured trace alongside the result. Use this when an agent needs to see why a rule fired (or didn't) -- the trace is the basis for rego_explain_decision.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInline input document.
pathsNoPolicy / data file or directory paths. Each must be inside an allowed root.
queryYesRego query to evaluate, e.g. "data.example.allow".
sourceNoInline Rego policy source. Mutually exclusive with `paths`.
partialNoRun partial evaluation rather than full evaluation.
unknownsNoRefs to treat as unknown during partial evaluation.
inputPathNoPath to a JSON input file. Mutually exclusive with `input`.
strictBuiltinErrorsNoTreat builtin errors as fatal instead of returning undefined.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, etc. The description adds that it uses --explain=full and returns a structured trace, which provides behavioral context beyond the annotations. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise at two sentences, front-loading the main behavior and use case. Every sentence adds value without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 8 parameters and no output schema, the description explains the core functionality and use case. It could be more complete by describing the trace structure, but the reference to rego_explain_decision partially compensates.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so each parameter already has a description. The tool description does not add additional semantics beyond the schema, meeting the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it evaluates Rego with '--explain=full' and returns a structured trace, distinguishing it from rego_eval which likely returns only results. It specifies the use case for understanding rule firing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says 'Use this when an agent needs to see why a rule fired (or didn't)', providing clear context. It mentions the trace is the basis for rego_explain_decision, implying an alternative for further analysis, though it could more directly name rego_eval for cases without trace.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_eval_with_profileEvaluate Rego with profilingA
Read-onlyIdempotent

Evaluate with --profile and return per-rule timing and evaluation counts. Use this to find hot rules in slow policies.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInline input document.
pathsNoPolicy / data file or directory paths. Each must be inside an allowed root.
queryYesRego query to evaluate, e.g. "data.example.allow".
sourceNoInline Rego policy source. Mutually exclusive with `paths`.
partialNoRun partial evaluation rather than full evaluation.
unknownsNoRefs to treat as unknown during partial evaluation.
inputPathNoPath to a JSON input file. Mutually exclusive with `input`.
strictBuiltinErrorsNoTreat builtin errors as fatal instead of returning undefined.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate read-only and idempotent behavior. The description adds valuable context about the profiling output (per-rule timing and counts) and the purpose. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two concise sentences that front-load the key information. Every word is meaningful with no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 8 parameters and no output schema, the description adequately explains the tool's purpose but lacks detail on the output structure (e.g., format of timing and counts). Annotations compensate for safety, so completeness is acceptable.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents each parameter. The description does not add extra detail beyond the overall purpose, but the baseline is 3 given full coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description explicitly states 'Evaluate with --profile and return per-rule timing and evaluation counts' and 'Use this to find hot rules in slow policies', providing a specific verb-resource combination and clear use case that distinguishes it from siblings like rego_eval or rego_eval_with_coverage.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description clearly indicates when to use: for profiling to find performance bottlenecks. However, it does not explicitly mention when not to use or list alternatives, though the sibling tools provide context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_explain_decisionExplain Rego decisionA
Read-onlyIdempotent

Evaluate a Rego query with full tracing and return a structured trace plus per-rule fired/not-fired summary. Use this when you need to answer "why was this denied?" -- the agent reads the structured trace and narrates the cause without re-implementing the trace parser.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInline input document.
pathsNoPolicy / data file or directory paths. Each must be inside an allowed root.
queryYesRego query to evaluate, e.g. "data.example.allow".
sourceNoInline Rego policy source. Mutually exclusive with `paths`.
partialNoRun partial evaluation rather than full evaluation.
unknownsNoRefs to treat as unknown during partial evaluation.
inputPathNoPath to a JSON input file. Mutually exclusive with `input`.
strictBuiltinErrorsNoTreat builtin errors as fatal instead of returning undefined.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate read-only, non-destructive, idempotent behavior. The description adds that evaluation is with full tracing and the output is a structured trace plus summary, and that the agent narrates without re-implementing parsing. This goes beyond annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences: first states what the tool does (verb+resource+output), second gives usage and agent behavior. No wasted words, front-loaded with key info.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 8 parameters and 100% schema coverage, the description explains the output and usage context. However, it could briefly mention mutual exclusivity of source/paths or partial vs full evaluation, but schema already does that.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. The description doesn't add parameter-specific details beyond what the schema already provides. It mentions 'full tracing' but that's about the tool's mode, not parameter meanings.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it evaluates a Rego query with full tracing and returns a structured trace plus per-rule summary, specifically for answering 'why was this denied?'. This verb+resource combination is distinct from siblings like rego_eval (no tracing) or rego_explain_undefined (focused on undefined).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says 'Use this when you need to answer "why was this denied?"', providing clear context. While it doesn't list when not to use, the surrounding sibling tools imply alternatives (e.g., rego_eval for normal evaluation).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_explain_undefinedExplain why a Rego query is undefinedA
Read-onlyIdempotent

Diagnose why a fully-qualified Rego query (e.g. "data.authz.allow") produces no value, or falls back to its default. Combines a plain eval, a full-trace eval, and per-condition AST analysis to identify the exact body expression blocking each rule. Handles both runtime failures (trace-based) and indexer elimination (standalone condition eval). A rule written with default allow := false always has a value, so queryResult reports default for it and the same per-rule breakdown follows: the question "why is allow false" is the question this answers. Returns a structured breakdown of which conditions blocked each rule plus a human-readable summary.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInput document (JSON value) for the query.
pathsNoPolicy .rego file paths to load. Mutually exclusive with source.
queryYesFully-qualified rule reference to explain, e.g. "data.authz.allow". Must match the path you would pass to rego_eval.
sourceNoInline Rego source to analyse. Mutually exclusive with paths.
inputPathNoPath to an input JSON file.

TDQS

A4.3/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description goes well beyond the annotations, revealing the internal strategy (plain eval + full-trace eval + per-condition AST analysis), the two handled failure modes (runtime failures and indexer elimination), the behavior for default rules (`queryResult` reports `default`), and the return shape (structured breakdown plus human-readable summary). Annotations already mark it read-only and idempotent, and nothing in the description contradicts them.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core purpose, then explains the method, the default-rule edge case, and finally the return value. Every sentence contributes useful context, though the technical method details and the restatement of the 'why is allow false' question add slight extra length. Overall it remains well-structured and readable.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the critical information an agent needs: query format, diagnostic behavior, special handling of default rules, and output contents, which matters because no output schema exists. It does not explicitly discuss the input/inputPath/paths/source parameters, but the schema fully describes those with 100% coverage, so this is not a significant gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so each parameter is already documented with meaningful detail. The tool description adds minimal parameter-specific information beyond the fully-qualified query concept, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Diagnose why a fully-qualified Rego query ... produces no value, or falls back to its default.' It clearly distinguishes this diagnostic tool from eval/explain siblings by describing the combined methodology (plain eval, full-trace eval, per-condition AST analysis) and explicitly addressing the default-rule case.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context for when to use the tool: when a fully-qualified Rego query is undefined or falls back to a default, and explicitly frames the question 'why is allow false' as the target. It does not explicitly name alternatives or state when not to use it, but the diagnostic intent is evident and the query path requirement is reinforced by the schema.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_fixAuto-fix Rego violationsA
DestructiveIdempotent

Run regal fix to automatically apply mechanical fixes for the five rules regal 0.30.0 supports: opa-fmt, use-rego-v1, use-assignment-operator, no-whitespace-comment, and directory-package-mismatch. Use dryRun: true to preview changes before modifying files. NOTE: directory-package-mismatch moves files to match their package path -- use disable: ["directory-package-mismatch"] to skip it. Files with uncommitted git changes require force: true. Requires regal.

ParametersJSON Schema
NameRequiredDescriptionDefault
forceNoAllow fixing files that have uncommitted git changes, or when the project is not a git repository. Without this flag regal refuses to touch uncommitted files.
pathsYesPolicy files or directories to fix. Each must be inside an allowed root (OPA_MCP_ALLOWED_PATHS).
dryRunNoPreview what would be fixed without modifying any files. Recommended before the first real run.
enableNoEnable specific fix rules.
disableNoDisable specific fix rules. Useful to skip directory-package-mismatch if you do not want files moved.
configFileNoPath to a Regal config file (.regal/config.yaml).
ignoreFilesNoGlob patterns to exclude from fixing.
enableCategoryNoEnable all rules in a category.
disableCategoryNoDisable all rules in a category.

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond annotations (destructiveHint, idempotentHint), description discloses that directory-package-mismatch moves files, requires force for uncommitted changes, and suggests dryRun for safety. Fully transparent about mutating behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences plus a note, all essential. Front-loaded with main action and critical usage guidance. No fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema, but the description covers what the tool does and key behavioral notes. Lacks explicit mention of return value (e.g., success/error messages), but for a fix tool this is minor. Overall sufficiently complete with given annotations and schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers 100% of parameters with descriptions. The description adds value by explaining the practical implications of key parameters (dryRun, force, disable) in context, aiding correct usage beyond schema alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool runs 'regal fix' to apply mechanical fixes and lists the five specific rules supported, distinguishing it from sibling tools like rego_lint or rego_format.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit guidance on using dryRun for preview, force for uncommitted files, and disabling directory-package-mismatch. Lacks explicit when-not-to-use advice, but the context is clear enough for correct invocation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_formatFormat RegoA
Read-onlyIdempotent

Format Rego source code using opa fmt. Returns the formatted source and a changed flag indicating whether the input was already canonical. When the source uses string interpolation ($"..." or $... syntax) and OPA v1.12.0 or v1.12.1 is detected, the tool warns about or blocks formatting due to a known OPA bug that corrupts { escape sequences (fixed in OPA v1.12.2).

ParametersJSON Schema
NameRequiredDescriptionDefault
sourceYesRego source code to format.

TDQS

A4.5/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes beyond annotations by detailing return values (formatted source and changed flag) and warning about a specific OPA bug that can corrupt escape sequences. This level of detail is valuable for agent decision-making.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences: first states core operation, second adds critical edge case. Extremely concise and well front-loaded with no extraneous information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite lacking an output schema, the description explains what is returned (formatted source + changed flag). Handles the single parameter fully and addresses version-specific behavior. Complete for its simplicity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with a single parameter 'source' having a clear description. The tool description adds no extra parameter context beyond the schema, so baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Clearly states 'Format Rego source code using `opa fmt`', specifying the verb (format), resource (Rego source code), and method. Distinguishes from siblings like rego_check and rego_lint which serve different purposes.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides clear context for when to use (formatting) and includes important caveats about OPA version and string interpolation bugs. Does not explicitly mention alternatives or when not to use, but given the distinct purpose, it's still effective.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_format_writeFormat Rego files in placeA
DestructiveIdempotent

Run opa fmt --write to canonically format one or more Rego files or directories in place. Use dryRun: true to preview which files would change without modifying them. Returns a list of files that were (or would be) reformatted. Unlike rego_format which returns formatted source as a string, this tool writes directly to disk. Supports regoV1, v0Compatible, and v1Compatible flags for version-specific formatting. If any file cannot be parsed, the operation is aborted and no files are written.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsYesPolicy files or directories to format in place. Each must be inside an allowed root (OPA_MCP_ALLOWED_PATHS).
dryRunNoPreview which files would be reformatted without modifying them. Recommended before the first real run.
regoV1NoFormat module(s) to be compatible with both Rego v1 and the current OPA version. Adds `import rego.v1` where missing.
v0CompatibleNoUse OPA behaviors and syntax prior to the v1.0 release.
v1CompatibleNoUse OPA v1.0-compatible behaviors.

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare destructiveHint=true and idempotentHint=true. Description adds details: writes to disk, dryRun preview, abort on parse failure. No contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Concise, front-loaded with main action, then key features (dryRun, return value, sibling differentiation, flags, error behavior). Every sentence adds value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with 5 params and no output schema, description covers return format, error behavior, version flags, and safety. Could mention idempotency or permissions, but redundant with annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%. Description adds meaning: paths must be within allowed root, dryRun for preview, regoV1 adds import rego.v1, v0Compatible/v1Compatible for version-specific formatting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Clearly states the tool runs `opa fmt --write` to format Rego files in place. Distinguishes from sibling `rego_format` by noting this writes to disk vs returning a string. Lists version flags.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly recommends using `dryRun: true` for preview and distinguishes from `rego_format`. Mentions abort on parse failure. Could explicitly state when not to use, but differentiation is sufficient.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_generate_test_skeletonGenerate Rego test skeletonA
Read-onlyIdempotent

Generate a *_test.rego skeleton from a policy. Parses the AST, finds each non-test rule, and emits one stub test per rule. Existing test_* and todo_test_* rules are skipped automatically -- only testable production rules get stubs. The AST is walked to infer which input.* fields the policy accesses; the inferred shape is used as the placeholder with input as {...} in each stub, so the developer only needs to fill in realistic values rather than guess the structure. With tableStyle: true, each stub uses an every tc in cases { ... } loop so you can add multiple input/expected pairs without duplicating assertion code. The inferredInputShape field in the response shows the detected shape for reference.

ParametersJSON Schema
NameRequiredDescriptionDefault
sourceYesRego source to generate tests for.
tableStyleNoGenerate table-driven test stubs instead of single-case stubs. Each rule gets a `cases` array and an `every tc in cases { ... }` assertion loop. Pair with `rego_test varValues: true` to see which case failed.

TDQS

A3.9/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds behavioral context: it skips existing test rules, infers input shape from AST, and with tableStyle generates array-based stubs. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured with clear first sentence stating purpose, followed by process details. It is moderately concise; every sentence contributes value (AST parsing, skipping rules, input inference, tableStyle behavior). Could potentially trim some elaboration but not wasteful.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, but description covers the output: stub tests, inferredInputShape response field, and behavior for tableStyle. For a 2-parameter tool with no enums, this is sufficient. Explains what the agent can expect from the tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. Description adds meaning to tableStyle (explains table-driven stubs with 'every tc in cases') and source (mentions AST parsing), but the schema already adequately describes each parameter. Description provides useful context but not essential beyond schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it generates a '*_test.rego' skeleton from a policy, with specific verb 'Generate' and resource 'Rego test skeleton'. It details the process: parsing AST, finding non-test rules, emitting stubs. This distinguishes it from sibling tools like rego_test (testing) and rego_format (formatting).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage for generating test skeletons from policy source, but does not explicitly state when to use vs alternatives, when not to use, or prerequisites. No guidance on choosing this over other code generation or testing tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_infer_input_schemaInfer input schemaA
Read-onlyIdempotent

Statically analyse one or more Rego policies and return a JSON Schema (draft-07) object describing every input.* field the policies read. Uses opa parse for AST-level analysis -- no running OPA server required. Correct starting point for writing integration tests, configuring opa check --schema validation, or documenting a policy API. Accepts inline source, individual files, or directories (walked recursively for *.rego files).

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsNoPolicy files or directories to analyse. Each must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Directories are walked recursively for *.rego files.
sourceNoInline Rego source to analyse. Mutually exclusive with paths.

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds context: uses AST-level analysis via opa parse, no OPA server needed, and accepts inline source, files, or directories. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Every sentence adds value: purpose, method, use cases, input formats. Well-structured with no fluff or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Though no output schema, the tool returns a JSON Schema object which is self-describing. Description covers input modes thoroughly. Slight lack of output format details is acceptable given the tool's nature.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description adds value by explaining mutual exclusivity of source and paths, allowed root constraint for paths, and recursive directory walking, beyond what the schema provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it statically analyzes Rego policies to return a JSON Schema of input.* fields. It uses specific verbs ('analyse', 'return') and resource ('input.* fields'), differentiating it from siblings like rego_eval or opa_query_decision.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description mentions it's a 'correct starting point' for integration tests, schema validation, or documenting policy API, implying when to use. It does not explicitly state when not to use or name alternatives, but the context is reasonably clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_inspectInspect bundle or policyA
Read-onlyIdempotent

Inspect an OPA bundle, policy directory, or single Rego file with opa inspect. Returns manifest data, namespaces, rule annotations, and (if signed) signature metadata.

ParametersJSON Schema
NameRequiredDescriptionDefault
targetYesPath to a bundle archive (`*.tar.gz`), directory, or single Rego file.

TDQS

A3.8/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safe, read-only nature is clear. The description adds behavioral context by detailing the return data (manifest, namespaces, annotations, signature metadata) and the accepted input types, which goes beyond the annotation flags.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise—two sentences that succinctly state the action and the outputs. Every word adds value; no redundancy or verbosity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple tool with one parameter and no output schema, the description adequately covers what the tool does and what it returns. Minor missing details like error behavior or format specifics are not critical given the tool's straightforward nature.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema covers the single 'target' parameter completely with a clear description of possible values. The tool description echoes this but adds no new semantic information beyond the schema. With 100% schema coverage, the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's action ('Inspect') and resource ('OPA bundle, policy directory, or single Rego file') and lists the specific outputs (manifest, namespaces, rule annotations, signature metadata). It distinguishes from siblings like rego_check or rego_eval by focusing on structural inspection.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description does not provide explicit guidance on when to use this tool versus alternatives. While the purpose implies it's for inspection of bundle structure, there is no mention of when not to use it or how it differs from similar sibling tools like rego_deps or rego_describe_policy.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_lintLint RegoA
Read-onlyIdempotent

Lint Rego source with the Regal linter. Returns categorized violations (style, bugs, idiomatic, performance) with file/line locations. Requires regal on PATH or REGAL_BINARY set; returns REGAL_NOT_FOUND otherwise. When called with inline source, location-bound rules whose verdict depends on the on-disk path (directory-package-mismatch) are auto-disabled to avoid temp-file false positives, and location.file is reported as <inline> instead of the randomized temp path. Re-enable those rules via enable if your workflow actually needs them.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsNoFilesystem paths to lint. Each path must be inside an allowed root (OPA_MCP_ALLOWED_PATHS).
enableNoEnable specific named rules.
sourceNoInline Rego source. Mutually exclusive with `paths`.
disableNoDisable specific named rules.
failLevelNoSeverity at which Regal returns a non-zero exit. Default: `error`.
configFileNoPath to a Regal config file (defaults to .regal/config.yaml lookup).
ignoreFilesNoGlob patterns to skip.
enableCategoryNoEnable entire rule categories.
disableCategoryNoDisable entire rule categories (e.g. style, idiomatic, bugs).

TDQS

A4.7/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond annotations (readOnly, idempotent), the description details error handling (returns REGAL_NOT_FOUND), inline source behavior (auto-disable directory-package-mismatch, mangled file location), and re-enabling via 'enable'. This adds significant behavioral value.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Four sentences, front-loaded with purpose, no waste. Efficiently conveys critical information without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers return format, error condition, tricky inline behavior, and re-enabling rules. Given 9 parameters (all schema-described) and no output schema, the description is sufficiently complete for an LLM to use the tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline 3. The description adds value by explaining global behaviors (e.g., inline source handling) that relate to parameters, but does not detail each parameter individually. Moderate added value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Lint Rego source with the Regal linter' and specifies the output format. It distinguishes itself from siblings (e.g., rego_check, rego_format) as the only lint tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides prerequisites ('Requires regal on PATH or REGAL_BINARY set') and explains when to use inline vs paths, including auto-disabling of location-bound rules. It lacks explicit 'when not to use' but covers key usage context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_migrate_v1Migrate Rego to v1 syntaxA
Read-onlyIdempotent

Migrate Rego v0 source to Rego v1 syntax in two phases: (1) opa fmt --rego-v1 auto-fixes reserved keywords (if, contains, every, in in rule heads) and adds import rego.v1; (2) opa check --v1-compatible validates the migrated source and reports any remaining issues that cannot be auto-fixed (e.g. removed builtins, semantic conflicts). Returns the migrated source and a changed flag even when check finds remaining errors -- this lets you inspect what changed and fix the remainder manually. If the source is completely unparseable, returns INVALID_REGO.

ParametersJSON Schema
NameRequiredDescriptionDefault
sourceYesRego v0 source to migrate to Rego v1 syntax. `opa fmt --rego-v1` auto-fixes reserved keywords and adds `import rego.v1`; any remaining issues are returned in `errors` so you can resolve them manually.

TDQS

A4.7/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds significant behavioral context beyond annotations: it details the two-phase process, explains that the tool returns migrated source and a changed flag even when errors remain, and specifies handling of invalid input (INVALID_REGO). This aligns with annotations (readOnlyHint, idempotentHint) without contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise (5 sentences) and front-loaded with the purpose. Each sentence adds distinct information: purpose, phases, return values, edge case. No wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity and no output schema, the description covers all essential aspects: input, process, output (migrated source, errors, INVALID_REGO), and behavior when errors remain. An agent has enough context to use the tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema coverage, baseline is 3. The description adds value by explaining the parameter's purpose in context of migration, though the schema description already repeats tool behavior. The single parameter is well-documented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: migrate Rego v0 to v1 syntax. It specifies the two-phase process (auto-fix with opa fmt --rego-v1 and validation with opa check --v1-compatible) and differentiates from other rego tools by covering both formatting and checking.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains when to use this tool (for migration) and what happens in each phase. It implicitly contrasts with siblings like rego_format and rego_check by describing combined functionality. However, it does not explicitly state when not to use it or list alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_parse_astParse Rego to ASTA
Read-onlyIdempotent

Parse Rego source to a JSON AST using opa parse. Returns the AST as a tree of nodes (package, imports, rules, expressions, terms). Use this when you need to introspect policy structure programmatically.

ParametersJSON Schema
NameRequiredDescriptionDefault
sourceYesRego source code to parse.

TDQS

A3.6/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds that the tool uses 'opa parse' and returns a tree of specific node types, but does not disclose additional behavioral traits like error handling, output format details, or performance characteristics. The added value beyond annotations is modest.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences: the first clearly states the action and implementation, the second provides usage context. No extraneous information; every sentence is purposeful. Highly concise and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple input (one string parameter), annotations covering safety/idempotency, and no output schema, the description is fairly complete. It explains what the tool does, how it works (opa parse), and the general output structure. Minor gap: no detail on error cases or output format beyond node types, but sufficient for a parse tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with a clear description for the 'source' parameter. The tool description adds little beyond the schema, stating it parses Rego to AST and mentioning the output structure, but does not enrich parameter semantics further. Baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool parses Rego source to a JSON AST using 'opa parse' and lists the AST node types. However, it does not distinguish from sibling tools like rego_check or rego_eval, though the purpose is unique among siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives a use case ('when you need to introspect policy structure programmatically') but does not provide explicit guidance on when not to use this tool or which alternatives exist. It implies usage context but lacks exclusion criteria.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_playground_shareShare Rego policy as a GitHub GistA

Share a Rego policy with teammates or create a reproducible example by publishing it as a public GitHub Gist. Returns { gistUrl, rawPolicyUrl, id }: the gistUrl renders the policy with syntax highlighting on github.com; the rawPolicyUrl can be passed directly to OPA (opa eval -d <rawPolicyUrl> <query>) or used as a data source in Conftest. When query, input, or data are supplied, a metadata.json file is bundled into the Gist so recipients have the full evaluation context to reproduce results. Each call creates a new Gist -- use the returned id to reference it later. Requires GITHUB_TOKEN in the environment (GitHub personal access token with the "gist" scope); returns GITHUB_TOKEN_MISSING with setup instructions if unset.

ParametersJSON Schema
NameRequiredDescriptionDefault
dataNoData document as a JSON string. Stored in metadata.json alongside the policy file.
inputNoInput document as a JSON string. Stored in metadata.json alongside the policy file.
queryNoDefault query to evaluate against the policy, e.g. "data.authz.allow". Stored in metadata.json alongside the policy file.
policyYesRego source code to share (the contents of a .rego file).
descriptionNoShort description for the Gist (shown on github.com/gists).

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses that each call creates a new Gist (non-idempotent), requires GITHUB_TOKEN with 'gist' scope, and explains the return values. Annotations provide readOnlyHint=false and destructiveHint=false, which are consistent with creating external resources. The description adds crucial behavioral context beyond annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a moderate-length paragraph that front-loads the purpose and then provides supporting details. Every sentence contributes useful information (return format, usage with OPA, metadata bundling, authentication). It could be slightly more concise but remains clear and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (5 parameters, 1 required, no output schema), the description effectively covers invocation, return values, authentication requirements, and how to use the results. It provides sufficient context for correct tool selection and usage without relying on additional documentation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents each parameter. However, the description adds value by explaining that query, input, and data are bundled into metadata.json for reproducibility, and that rawPolicyUrl can be used directly with OPA or Conftest. This enhances practical understanding beyond schema definitions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: sharing a Rego policy as a public GitHub Gist for team collaboration or reproducible examples. It distinguishes itself from sibling tools (like rego_eval or rego_test) by focusing on sharing rather than evaluation or testing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains when to use the tool (share policy, create reproducible example) and provides context for optional parameters (query, input, data bundle into metadata.json). It also notes the prerequisite GITHUB_TOKEN and what happens if missing. However, it does not explicitly state when not to use it or compare directly to alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_policy_diffDiff two Rego policiesA
Read-onlyIdempotent

Evaluate the same query against two policies (or two versions of the same policy) and compare the results. Both evaluations run in parallel. Returns equal: true/false, the raw result from each side, and changedPaths -- the dot/bracket paths that differ. Useful for verifying that a refactor preserves behavior, or understanding exactly where two policies diverge. Each side takes either inline source (sourceA/sourceB) or a file/directory path (pathA/pathB). The same input and query are used for both evaluations.

ParametersJSON Schema
NameRequiredDescriptionDefault
inputNoInline input document (JSON). Mutually exclusive with inputPath.
pathANoFile or directory path for policy A. Must be inside an allowed root. Mutually exclusive with sourceA.
pathBNoFile or directory path for policy B. Must be inside an allowed root. Mutually exclusive with sourceB.
queryYesThe query to evaluate against both policies, e.g. "data.example.allow".
sourceANoInline Rego source for policy A. Mutually exclusive with pathA.
sourceBNoInline Rego source for policy B. Mutually exclusive with pathB.
dataPathsNoAdditional data or policy paths loaded for both evaluations. Each must be inside an allowed root.
inputPathNoPath to a JSON input file. Must be inside an allowed root. Mutually exclusive with input.

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false, so the tool is safe. The description adds that evaluations run in parallel and details the return format ('equal: true/false', raw results, 'changedPaths'). This goes well beyond the annotations, providing full behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences, front-loading the core purpose and then detailing behavior and parameters. Every sentence adds value with no redundancy or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 8 parameters, 1 required, and no output schema, the description covers return values, parameter relationships, and key behavioral traits. It lacks error conditions or edge cases but is sufficient for a diff tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description adds meaning by explaining mutual exclusivity between source/path pairs and that the same input and query are used for both evaluations. This enriches understanding beyond the schema alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool evaluates the same query against two policies and compares results. It specifies the verb ('Evaluate' and 'compare'), the resources ('two policies or two versions'), and distinguishes from siblings by focusing on diffing rather than single evaluation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit use cases ('verifying that a refactor preserves behavior' and 'understanding exactly where two policies diverge') and explains parameter relationships (mutual exclusivity of sourceA/pathA). However, it does not explicitly state when not to use this tool or list alternatives among siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_security_auditRego security auditA
Read-onlyIdempotent

Run regal lint restricted to the security and bugs categories across one or more policy directories. Returns findings grouped by severity (high/medium) with remediation guidance. Use this for a periodic fleet-wide security sweep rather than per-file style review. Requires regal.

ParametersJSON Schema
NameRequiredDescriptionDefault
pathsYesPolicy directories or files to audit. Each must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Pass the root of your policy fleet to scan everything at once.
configFileNoPath to a Regal config file. Useful when your repo has custom rule configuration.
ignoreFilesNoGlob patterns to exclude from the audit.

TDQS

A4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. Description adds that it returns findings grouped by severity with remediation guidance and requires regal, which provides useful context beyond annotations but does not contradict them.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three concise sentences: purpose, usage guidance, prerequisite. Front-loaded with key information. No unnecessary words or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema, but description explains output format (findings by severity with remediation). Missing details on error handling or invalid paths, but overall sufficient given annotations and schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with descriptions for each parameter. Description adds minimal extra meaning (e.g., 'Pass the root of your policy fleet to scan everything at once' for paths), but does not significantly supplement the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description clearly states it runs 'regal lint restricted to the security and bugs categories' across policy directories, which is a specific verb-resource combination. It distinguishes from sibling 'rego_lint' by focusing on security and bugs categories and mentioning fleet-wide sweep.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit usage guidance: 'Use this for a periodic fleet-wide security sweep rather than per-file style review.' Also states prerequisite 'Requires regal.' Does not explicitly name alternatives but context implies different tool for per-file review.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_suggest_fixSuggest fix for Rego diagnosticsA
Read-onlyIdempotent

Map common Rego compile errors and Regal lint findings to mechanical fix suggestions. Pass diagnostics from rego_check or rego_lint. Returns one suggestion per input diagnostic; confidence is high for well-known patterns, medium for partial matches, low for everything else.

ParametersJSON Schema
NameRequiredDescriptionDefault
diagnosticsYesDiagnostics from rego_check or rego_lint.

TDQS

A4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive. The description adds that it returns one suggestion per diagnostic and confidence levels (high/medium/low). This provides useful behavioral context beyond annotations, though it does not detail the output structure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with purpose, no unnecessary words. Every sentence adds value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity and no output schema, the description explains input source, output quantity, and confidence levels. It does not describe the suggestion structure, but for a low-complexity tool, this is nearly complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with descriptions for all fields. The description only adds that diagnostics should come from rego_check or rego_lint, which is helpful but minimal. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it maps compile errors and lint findings to fix suggestions, and specifies the source diagnostics. However, it does not explicitly differentiate from sibling tool rego_fix, which may apply fixes, leaving some ambiguity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly instructs to pass diagnostics from rego_check or rego_lint, providing clear usage context. Does not mention when not to use or alternatives, but the context is sufficient for an AI agent.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_testRun Rego testsA
Read-onlyIdempotent

Run Rego unit tests with opa test. Returns aggregate pass/fail/skip/error counts plus per-test records. errored counts tests OPA could not evaluate (a rule conflict, a raising built-in); such a test is neither a pass nor a failure, and a suite with any is not passing. Tests live in *_test.rego files; rule names beginning with test_ are picked up automatically. Use runPattern to filter by name regex; when no tests match, the error hint includes the pattern you supplied. Use threshold to gate on minimum coverage (returns COVERAGE_BELOW_THRESHOLD on failure). Use varValues: true with verbose: true to include local variable bindings in the trace -- essential for debugging table-driven tests written with every tc in cases { ... } to identify which case caused a failure. When tests use the test_x[case] parameterized form, OPA reports the rule as a single test whatever the number of cases; parameterizedGroups maps the rule name to a record per case and caseCounts totals them, so a failing rule says which case failed. Use ignorePatterns to exclude generated or fixture files. Use bundle: true when testing bundle-structured policy directories. Use timeout to raise the per-test limit beyond OPA's default 5s. Note: enabling coverage or threshold switches OPA to coverage-report output mode -- per-test counts are unavailable but coverage and coveragePct fields are populated.

ParametersJSON Schema
NameRequiredDescriptionDefault
countNoNumber of times to repeat the suite (`--count N`). Default is 1. Useful for catching flaky tests. OPA stops at the first repetition that fails, so `repetitions` in the output reports how many actually ran, and each test is listed once carrying its worst outcome across them.
pathsYesTest directories or files. `opa test` looks for `*_test.rego` siblings of source files.
bundleNoLoad paths as OPA bundle roots (`--bundle`). Required when testing policies structured as bundles with a `manifest.json` at the root. Not needed for plain policy directories.
explainNoAdd a query-explanation trace to test records (`--explain`). `fails` traces only failing tests, `full` traces everything, `notes` surfaces `trace()` notes, `debug` is most verbose. Populates each record's `trace` field; pair with `verbose: true` for the human-readable trace output too.
timeoutNoPer-test timeout as a Go duration string, e.g. `"30s"` or `"2m"` (`--timeout`). OPA's default is 5s. Increase for tests that load large policy sets or call slow built-ins.
verboseNoEmit per-test pass/fail details.
coverageNoInclude per-line coverage data. Switches output to coverage-report mode: test record counts are not available, but `coverage` and `coveragePct` fields are populated.
thresholdNoMinimum coverage percentage required (0–100). Returns COVERAGE_BELOW_THRESHOLD when actual coverage falls below this value. Implicitly enables coverage-report output mode.
varValuesNoInclude local variable bindings in trace output (`--var-values`). When a table-driven test using `every tc in cases { ... }` fails, the trace shows which `tc` triggered the failure. Has no effect unless `verbose: true` is also set (OPA only emits trace entries in verbose mode).
runPatternNoRun only tests whose names match this regular expression (passed as `--run`).
v1CompatibleNoOpt in to OPA v1.0-compatible behaviors (`--v1-compatible`).
ignorePatternsNoGlob patterns for files to exclude from the test run (`--ignore <pattern>`). Pass one pattern per array element. Useful for excluding generated or fixture files that contain no tests (e.g. `["*_generated.rego", "fixtures/**"]`).

TDQS

A4.2/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint/idempotentHint/destructiveHint, and the description adds substantial non-obvious behavior: `errored` tests are neither pass nor fail and a suite with any is not passing; enabling `coverage`/`threshold` switches to coverage-report mode which drops per-test counts; repeated runs stop at the first failing repetition; and parameterized `test_x[case]` rules are reported as a single test unless disambiguated via `parameterizedGroups`. These behaviors are invisible in the schema and are exactly what an agent needs to interpret results correctly.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded correctly with purpose and result shape in the first two sentences, and every subsequent clause carries real operational meaning. The length is mostly earned given 12 parameters, hidden mode interactions, and no output schema; however, several clauses duplicate schema text (timeout default, coverage-mode switch, threshold return value), and the single unbroken prose block scans harder than bulleted parameter guidance would.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the burden of explaining return values and does so well: errored counts, `parameterizedGroups`, `caseCounts`, `coverage`/`coveragePct`, `repetitions`, and `trace` are all named. Remaining gaps are minor: no guidance on when `v1Compatible` matters and no explicit note that multi-root suites belong to `rego_test_multiroot`.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds genuine value beyond the schema: the table-driven-test debugging rationale for `varValues`, the error-hint-includes-pattern behavior for `runPattern`, and the `parameterizedGroups`/`caseCounts` interpretation for parameterized tests. Some overlap exists — `threshold`'s COVERAGE_BELOW_THRESHOLD return and the coverage-mode switch are restated from the schema — but the net addition justifies above baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource statement — 'Run Rego unit tests with `opa test`' — and immediately specifies the result shape (aggregate pass/fail/skip/error counts plus per-test records). It does not, however, distinguish itself from the closely overlapping sibling `rego_test_multiroot`, so an agent selecting between the two must infer the difference from the name alone.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Rich conditional guidance at the parameter level: 'Use `runPattern` to filter by name regex', 'Use `bundle: true` when testing bundle-structured policy directories', 'Use `varValues: true` with `verbose: true`' for debugging table-driven tests, and 'Use `threshold` to gate on minimum coverage'. What's absent is tool-selection guidance — when to choose this over `rego_test_multiroot`, `rego_eval`, or `conftest_test`.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_test_multirootRun Rego tests across multiple rootsA
Read-onlyIdempotent

Run opa test once per root and aggregate results. Solves the package-conflict problem that occurs when opa test . is run on a repo with multiple independent package namespaces (OPA issue #4724). Two modes: explicit (supply root list with optional per-root include paths for shared libraries) and scan (auto-discover leaf test roots using the leaf rule -- a directory is a root only if it directly contains *_test.rego files and none of its eligible subdirectories do, preventing OPA's automatic recursion from double-running tests). Use sharedPaths in scan mode to add shared library directories to every root's invocation without including them in discovery. Coverage and threshold work per-root; overallCoveragePct is the mean across roots that have coverage data.

ParametersJSON Schema
NameRequiredDescriptionDefault
rootsNoExplicit list of test root directories. Use when roots are known upfront or when scan mode cannot determine the correct roots. Mutually exclusive with `scanDir`.
scanDirNoTop-level directory to scan for test roots. Uses the leaf rule: a directory is a root only if it directly contains `*_test.rego` files and none of its eligible subdirectories do. Mutually exclusive with `roots`.
verboseNoEmit per-test pass/fail details for each root.
coverageNoInclude per-line coverage data per root. Switches output to coverage-report mode: test record counts are not available, but `coverage`, `coveragePct`, and `overallCoveragePct` fields are populated.
maxDepthNoMaximum directory depth to scan. Default: 10. Only used with `scanDir`.
maxRootsNoMaximum number of test roots allowed. Returns INVALID_INPUT if scan finds more. Default: 50. Only used with `scanDir`.
thresholdNoMinimum coverage percentage required per root (0-100). Roots below threshold have `thresholdMet: false` in their result. Implicitly enables coverage-report output mode.
varValuesNoInclude local variable bindings in trace output (`--var-values`). Only useful with `verbose: true`.
runPatternNoRun only tests whose names match this regular expression (passed as `--run` to each root).
sharedPathsNoPaths added to every root's `opa test` invocation and excluded from auto-discovery. Use for shared library directories that all roots import from.
ignorePatternsNoAdditional directory name patterns to skip during scan (e.g., ["vendor", "*.generated"]). Supports `*` wildcards. Only used with `scanDir`.

TDQS

A4.8/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds extensive behavioral detail beyond annotations, including the leaf discovery rule, coverage mode switching, per-root threshold behavior, and interaction of parameters like `varValues` requiring `verbose`. No contradictions with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise for the complexity, covering essential details in a few sentences. Could benefit from bullet points for the two modes, but the prose is clear and front-loaded with the core purpose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the complexity (11 parameters, two modes, scan logic, coverage nuances) and lack of output schema, the description thoroughly explains all necessary context for correct invocation, including edge cases like the leaf rule and mutual exclusivity of `roots` and `scanDir`.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

All 11 parameters have schema descriptions (100% coverage). The overall description adds contextual understanding of parameter interactions (e.g., `coverage` and `threshold` affecting output mode, `sharedPaths` excluded from scan). Slightly more structured parameter grouping would improve, but still adds value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool runs `opa test` once per root and aggregates results, solving the package-conflict problem (OPA issue #4724). It distinguishes itself from sibling tools like `rego_test` by specifying multi-root handling.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly describes two modes (`explicit` and `scan`) with their use cases, when each should be used, and mentions when to use alternative like `rego_test` for single roots. Provides clear context for `sharedPaths` and coverage options.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rego_verifyFormally verify a Rego policy ruleA
Read-onlyIdempotent

Formally verify a property about a Rego rule using SMT solving (Microsoft Z3). Unlike testing, this checks ALL possible inputs and either proves the property holds or returns a concrete counterexample input that falsifies it. Supports equality, comparison, startswith, endswith, contains, and simple regex.match patterns (prefix: ^lit.*, suffix: .lit$, exact: ^lit$, contains: .lit., wildcard: .). Complex regex patterns (character classes, quantifiers, alternation) return INCONCLUSIVE. Also reports INCONCLUSIVE for negation-as-failure (not), comprehensions, partial set and object rules (deny contains msg), functions, else chains, and any operand it cannot encode. A body that reads an absent field is undefined rather than true, so always_true holds only if the rule is also true for an empty input: a rule requiring input.x will be answered with the counterexample {}.

ParametersJSON Schema
NameRequiredDescriptionDefault
kindYesProperty to prove: always_true - rule is true for every possible input (finds inputs that violate this) never_true - rule is never true for any input (finds inputs that trigger it) satisfiable - at least one input exists where rule is true (returns a witness)
ruleYesName of the rule to verify (e.g. "allow", "deny").
sourceYesRego source to verify.

TDQS

A4.7/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description extensively discloses behaviors beyond the annotations: it returns concrete counterexamples, reports INCONCLUSIVE for specific unsupported constructs, treats absent fields as undefined, and explains the empty-input caveat for always_true. Annotations only declare read-only/idempotent, so this adds substantial value.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is long but information-dense; every clause contributes a necessary limitation or behavioral detail. It is front-loaded with the core verification promise before moving to edge cases, making it efficiently scannable for an agent.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite having no output schema, the description covers all major outcomes: proof, counterexample, INCONCLUSIVE, unsupported language features, and undefined-field semantics. An agent has enough information to invoke the tool correctly and interpret likely results.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description adds semantic depth beyond the schema by clarifying what always_true means for absent fields and how a rule requiring input.x yields the counterexample {}, which enriches the enum definitions in the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: formally verify a property about a Rego rule using SMT solving. It clearly distinguishes itself from testing by checking ALL possible inputs and from sibling eval/test tools by emphasizing proof or counterexample output.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear context for when to use this tool: when exhaustive verification is desired instead of testing, and it explains when results will be INCONCLUSIVE due to unsupported constructs. It does not explicitly name sibling alternatives, but the 'Unlike testing' contrast and limitation list provide practical usage guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. 16 tool updatesv0.5.0
    • Changedconftest_pull1 field changed
      • changedInput schema / properties / policy / description
        Previous value: -"Local directory where the pulled policies will be written. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Defaults to `./policy` (conftest's convention)."New value: +"Local directory where the pulled policies will be written. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS). Omitted, it falls back to `policy` in the working directory of the server process, the conftest convention, which must itself sit inside an allowed root. The directory is emptied before the pull, so do not point it at one holding anything you want to keep."
    • Changedconftest_push1 field changed
      • changedInput schema / properties / policy / description
        Previous value: -"Path to the local directory containing Rego policies to push. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS) and must exist. Defaults to `./policy` (conftest's convention)."New value: +"Path to the local directory containing Rego policies to push. Must be inside an allowed root (OPA_MCP_ALLOWED_PATHS) and must exist. Omitted, it falls back to `policy` in the working directory of the server process, the conftest convention, which must itself sit inside an allowed root."
    • Changedconftest_test4 fields changed
      • changedInput schema / properties / inlineConfigParser / description
        Previous value: -"Parser to use for `inlineConfig`. Valid values: yaml (default), json, toml, hcl1, hcl2, ini, xml, dotenv, cue, jsonnet, properties, edn, hocon, dockerfile. Ignored when `files` is used (conftest infers the parser from each file's extension, unless `parser` is set)."New value: +"Parser to use for `inlineConfig`. One of: cue, dockerfile, dotenv, edn, hcl1, hcl2, hocon, ignore, ini, json, jsonnet, nginx, properties, spdx, textproto, toml, vcl, xml, yaml. Defaults to yaml. Ignored when `files` is used (conftest infers the parser from each file's extension, unless `parser` is set)."
      • addedInput schema / properties / inlineConfigParser / enum
        Added value: +[
        +  "cue",
        +  "dockerfile",
        +  "dotenv",
        +  "edn",
        +  "hcl1",
        +  "hcl2",
        +  "hocon",
        +  "ignore",
        +  "ini",
        +  "json",
        +  "jsonnet",
        +  "nginx",
        +  "properties",
        +  "spdx",
        +  "textproto",
        +  "toml",
        +  "vcl",
        +  "xml",
        +  "yaml"
        +]
      • changedInput schema / properties / parser / description
        Previous value: -"Force a specific parser for all input `files` via conftest's global `--parser` flag, overriding extension-based detection. Useful for files whose extension does not match their format (e.g. parse a `.tfstate` file as `json`). Valid values: yaml, json, toml, hcl1, hcl2, ini, xml, dotenv, cue, jsonnet, properties, edn, hocon, dockerfile. For `inlineConfig`, prefer `inlineConfigParser`."New value: +"Force a specific parser for all input `files` via conftest's global `--parser` flag, overriding extension-based detection. Useful for files whose extension does not match their format (e.g. parse a `.tfstate` file as `json`). One of: cue, dockerfile, dotenv, edn, hcl1, hcl2, hocon, ignore, ini, json, jsonnet, nginx, properties, spdx, textproto, toml, vcl, xml, yaml. For `inlineConfig`, prefer `inlineConfigParser`."
      • addedInput schema / properties / parser / enum
        Added value: +[
        +  "cue",
        +  "dockerfile",
        +  "dotenv",
        +  "edn",
        +  "hcl1",
        +  "hcl2",
        +  "hocon",
        +  "ignore",
        +  "ini",
        +  "json",
        +  "jsonnet",
        +  "nginx",
        +  "properties",
        +  "spdx",
        +  "textproto",
        +  "toml",
        +  "vcl",
        +  "xml",
        +  "yaml"
        +]
    • Changedopa_bundle_build3 fields changed
      • changedInput schema / properties / bundle / description
        Previous value: -"Load `paths` as bundle files or root directories (`--bundle`). Required when rebuilding or re-signing an existing bundle."New value: +"Load `paths` as bundle files or root directories (`--bundle`). Implied by `signingKey` and `verificationKey`; set it explicitly to rebuild an existing bundle without signing."
      • changedInput schema / properties / signingKey / description
        Previous value: -"Path to a signing key for inline signing."New value: +"Path to a PEM private key for signing the built bundle (`--signing-key`). Implies `bundle: true`, which OPA requires for signing."
      • changedInput schema / properties / verificationKey / description
        Previous value: -"Path to a PEM public key (or HMAC secret file) used to re-verify an existing signed bundle during the build (`--verification-key`). Pair with `bundle: true`."New value: +"Path to a PEM public key (or HMAC secret file) used to re-verify an existing signed bundle during the build (`--verification-key`). Implies `bundle: true`, which OPA requires for verification."
    • Changedopa_bundle_sign5 fields changed
      • changedInput schema / properties / bundle / description
        Previous value: -"Path to a bundle directory or archive. Must be in an allowed root."New value: +"Path to a bundle directory or `.tar.gz` archive. Must be inside an allowed root."
      • changedInput schema / properties / claimsFile / description
        Previous value: -"Path to extra claims to include in the signature."New value: +"Path to a JSON file of extra claims to sign, such as {\"keyid\": \"...\", \"scope\": \"...\"}. Must be inside an allowed root."
      • addedInput schema / properties / outputDir
        Added value: +{
        +  "description": "For an archive, the directory that receives `.signatures.json`; defaults to the archive's own directory. Must exist and be inside an allowed root. Not accepted for a directory bundle, which is signed in place.",
        +  "type": "string"
        +}
      • changedInput schema / properties / signingAlg / description
        Previous value: -"Signing algorithm (e.g. RS256). Default: RS256."New value: +"Signing algorithm: RS256 (default), RS384, RS512, PS256, PS384, PS512, ES256, ES384, ES512, HS256, HS384, HS512."
      • changedInput schema / properties / signingKey / description
        Previous value: -"Path to the signing key."New value: +"Path to the PEM private key (RSA or ECDSA), or for HMAC algorithms a file holding the secret. Must be inside an allowed root."
    • Changedopa_bundle_verify4 fields changed
      • changedInput schema / properties / scope / description
        Previous value: -"Expected `scope` value in the bundle signature. Required when the bundle was signed with `--scope`."New value: +"Expected `scope` claim in the signature. Pass exactly the value the bundle was signed with, and nothing if it was signed without one; the failure reason is scope_mismatch otherwise."
      • addedInput schema / properties / v0Compatible
        Added value: +{
        +  "description": "Load the bundle as Rego v0 (`--v0-compatible`). A policy written before Rego v1 otherwise fails to load, after the signature and digests have already been checked.",
        +  "type": "boolean"
        +}
      • changedInput schema / properties / verificationKey / description
        Previous value: -"Path to the PEM file containing the RSA or ECDSA public key, or the path to the HMAC secret file. Must be inside an allowed root."New value: +"Path to the PEM file containing the RSA or ECDSA public key, or for HMAC algorithms a file holding the secret. Must be inside an allowed root."
      • changedInput schema / properties / verificationKeyId / description
        Previous value: -"Key ID that must match the `keyid` field in the bundle signature. Required when the bundle was signed with `--public-key-id`."New value: +"Name the key is registered under for OPA (`--verification-key-id`, default `default`). With a single key OPA verifies against it regardless of the signature keyid claim, so this rarely needs setting."
    • Changedopa_delete_data2 fields changed
      • addedInput schema / properties / segments
        Added value: +{
        +  "description": "Path as literal key segments, e.g. [\"labels\", \"app.kubernetes.io/name\"]. Use instead of `path` when a key contains a dot or a slash.",
        +  "items": {
        +    "minLength": 1,
        +    "type": "string"
        +  },
        +  "minItems": 1,
        +  "type": "array"
        +}
      • removedInput schema / required
        Removed value: -[
        -  "path"
        -]
    • Changedopa_exec1 field changed
      • changedInput schema / properties / decision / description
        Previous value: -"The policy entrypoint to evaluate for each input, e.g. `\"data.authz.allow\"` or `\"data.policy.violations\"`. Must be a fully-qualified Rego reference."New value: +"The policy entrypoint to evaluate for each input, e.g. `\"authz/allow\"`. `opa exec` names a decision by slash-separated path with no `data.` prefix; the Rego reference forms (`data.authz.allow`, `authz.allow`) are accepted here and converted, because passing one straight through leaves every file undefined."
    • Changedopa_get_data2 fields changed
      • addedInput schema / properties / segments
        Added value: +{
        +  "description": "Path as literal key segments, e.g. [\"labels\", \"app.kubernetes.io/name\"]. Use instead of `path` when a key contains a dot or a slash.",
        +  "items": {
        +    "minLength": 1,
        +    "type": "string"
        +  },
        +  "minItems": 1,
        +  "type": "array"
        +}
      • removedInput schema / required
        Removed value: -[
        -  "path"
        -]
    • Changedopa_get_policy1 field changed
      • addedInput schema / properties / includeAst
        Added value: +{
        +  "description": "Include OPA's parsed AST alongside the source. Off by default.",
        +  "type": "boolean"
        +}
    • Changedopa_list_policies3 fields changed
      • addedInput schema / additionalProperties
        Added value: +false
      • addedInput schema / properties / includeAst
        Added value: +{
        +  "description": "Include each policy's parsed AST. Off by default; it is roughly forty times the size of the source and will exceed the response cap on all but the smallest servers.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / includeSource
        Added value: +{
        +  "description": "Include each policy's Rego source. Off by default: fetch one policy with `opa_get_policy` rather than every policy at once.",
        +  "type": "boolean"
        +}
    • Changedopa_patch_data3 fields changed
      • changedInput schema / properties / path / description
        Previous value: -"Data path the patch is applied to. Use \"\" for the root."New value: +"Data path the patch is applied to."
      • addedInput schema / properties / segments
        Added value: +{
        +  "description": "Path as literal key segments, e.g. [\"labels\", \"app.kubernetes.io/name\"]. Use instead of `path` when a key contains a dot or a slash.",
        +  "items": {
        +    "minLength": 1,
        +    "type": "string"
        +  },
        +  "minItems": 1,
        +  "type": "array"
        +}
      • changedInput schema / required
        Previous value: -[
        -  "path",
        -  "operations"
        -]New value: +[
        +  "operations"
        +]
    • Changedopa_put_data2 fields changed
      • addedInput schema / properties / segments
        Added value: +{
        +  "description": "Path as literal key segments, e.g. [\"labels\", \"app.kubernetes.io/name\"]. Use instead of `path` when a key contains a dot or a slash.",
        +  "items": {
        +    "minLength": 1,
        +    "type": "string"
        +  },
        +  "minItems": 1,
        +  "type": "array"
        +}
      • removedInput schema / required
        Removed value: -[
        -  "path"
        -]
    • Changedopa_query_decision2 fields changed
      • addedInput schema / properties / segments
        Added value: +{
        +  "description": "Path as literal key segments, e.g. [\"labels\", \"app.kubernetes.io/name\"]. Use instead of `path` when a key contains a dot or a slash.",
        +  "items": {
        +    "minLength": 1,
        +    "type": "string"
        +  },
        +  "minItems": 1,
        +  "type": "array"
        +}
      • removedInput schema / required
        Removed value: -[
        -  "path"
        -]
    • Changedrego_bench1 field changed
      • changedInput schema / properties / count / description
        Previous value: -"Number of benchmark iterations. Defaults to OPA's built-in default."New value: +"Number of times to repeat the benchmark (`--count N`). Defaults to OPA's built-in default of one. Every repetition is returned in `runs`; the top-level figures come from the fastest of them."
    • Changedrego_test1 field changed
      • changedInput schema / properties / count / description
        Previous value: -"Number of times to repeat each test (`--count N`). Default is 1. Useful for measuring repeatability or catching flaky tests under load."New value: +"Number of times to repeat the suite (`--count N`). Default is 1. Useful for catching flaky tests. OPA stops at the first repetition that fails, so `repetitions` in the output reports how many actually ran, and each test is listed once carrying its worst outcome across them."
  2. 1 tool updatev0.3.0
    • Changedrego_capabilities1 field changed
      • changedInput schema / properties / version / description
        Previous value: -"A specific OPA capabilities version (e.g. \"v0.69.0\"). When neither flag is set, lists available versions."New value: +"A specific OPA capabilities version (e.g. \"v1.19.0\"). When neither flag is set, lists available versions."
  3. 5 tool updatesv0.1.20
    • Changedconftest_test2 fields changed
      • changedInput schema / properties / inlineConfigParser / description
        Previous value: -"Parser to use for `inlineConfig`. Valid values: yaml (default), json, toml, hcl1, hcl2, ini, xml, dotenv, cue, jsonnet, properties, dockerfile. Ignored when `files` is used (conftest infers the parser from each file's extension)."New value: +"Parser to use for `inlineConfig`. Valid values: yaml (default), json, toml, hcl1, hcl2, ini, xml, dotenv, cue, jsonnet, properties, edn, hocon, dockerfile. Ignored when `files` is used (conftest infers the parser from each file's extension, unless `parser` is set)."
      • addedInput schema / properties / parser
        Added value: +{
        +  "description": "Force a specific parser for all input `files` via conftest's global `--parser` flag, overriding extension-based detection. Useful for files whose extension does not match their format (e.g. parse a `.tfstate` file as `json`). Valid values: yaml, json, toml, hcl1, hcl2, ini, xml, dotenv, cue, jsonnet, properties, edn, hocon, dockerfile. For `inlineConfig`, prefer `inlineConfigParser`.",
        +  "type": "string"
        +}
    • Changedopa_bundle_build6 fields changed
      • addedInput schema / properties / bundle
        Added value: +{
        +  "description": "Load `paths` as bundle files or root directories (`--bundle`). Required when rebuilding or re-signing an existing bundle.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / ignore
        Added value: +{
        +  "description": "File/directory name patterns to ignore during loading (`--ignore`), e.g. `[\".*\"]` to skip hidden files. These are name patterns, not filesystem paths.",
        +  "items": {
        +    "type": "string"
        +  },
        +  "type": "array"
        +}
      • addedInput schema / properties / pruneUnused
        Added value: +{
        +  "description": "Exclude dependents of entrypoints that are not reachable from them (`--prune-unused`). Most useful alongside `entrypoints`.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / v1Compatible
        Added value: +{
        +  "description": "Opt in to OPA v1.0-compatible behaviors (`--v1-compatible`). Affects the built bundle's runtime semantics.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / verificationKey
        Added value: +{
        +  "description": "Path to a PEM public key (or HMAC secret file) used to re-verify an existing signed bundle during the build (`--verification-key`). Pair with `bundle: true`.",
        +  "type": "string"
        +}
      • addedInput schema / properties / verificationKeyId
        Added value: +{
        +  "description": "Key ID for verification (`--verification-key-id`, OPA default `default`).",
        +  "type": "string"
        +}
    • Changedopa_exec6 fields changed
      • changedInput schema / properties / dataPaths / description
        Previous value: -"Policy and/or data file or directory paths to load. Mutually exclusive with `bundle`."New value: +"Policy and/or data file or directory paths, each loaded as an OPA bundle root (opa exec loads policy only via bundles). Mutually exclusive with `bundle`."
      • addedInput schema / properties / fail
        Added value: +{
        +  "description": "CI gate: report `failed: true` when any decision is undefined or errors. Mutually exclusive with `failDefined` and `failNonEmpty`.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / failDefined
        Added value: +{
        +  "description": "CI gate: report `failed: true` when any decision is defined or errors. Use when a defined result means a violation. Mutually exclusive with `fail` and `failNonEmpty`.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / failNonEmpty
        Added value: +{
        +  "description": "CI gate: report `failed: true` when any decision result is non-empty or errors. Mutually exclusive with `fail` and `failDefined`.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / timeout
        Added value: +{
        +  "description": "Per-exec evaluation timeout as a Go duration, e.g. `\"30s\"` or `\"5m\"`. Still bounded by the server subprocess timeout (OPA_MCP_TIMEOUT_MS).",
        +  "type": "string"
        +}
      • addedInput schema / properties / v1Compatible
        Added value: +{
        +  "description": "Opt in to OPA v1.0-compatible behaviors (`--v1-compatible`).",
        +  "type": "boolean"
        +}
    • Changedrego_check2 fields changed
      • addedInput schema / properties / bundle
        Added value: +{
        +  "description": "Load `paths` as bundle files or root directories (`--bundle`). Only valid with `paths`, not inline `source`.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / maxErrors
        Added value: +{
        +  "description": "Maximum number of errors to collect before `opa check` aborts compilation (`--max-errors`, OPA default 10). Raise it to surface more diagnostics from a badly broken policy in a single pass.",
        +  "minimum": 1,
        +  "type": "integer"
        +}
    • Changedrego_test2 fields changed
      • addedInput schema / properties / explain
        Added value: +{
        +  "description": "Add a query-explanation trace to test records (`--explain`). `fails` traces only failing tests, `full` traces everything, `notes` surfaces `trace()` notes, `debug` is most verbose. Populates each record's `trace` field; pair with `verbose: true` for the human-readable trace output too.",
        +  "enum": [
        +    "fails",
        +    "full",
        +    "notes",
        +    "debug"
        +  ],
        +  "type": "string"
        +}
      • addedInput schema / properties / v1Compatible
        Added value: +{
        +  "description": "Opt in to OPA v1.0-compatible behaviors (`--v1-compatible`).",
        +  "type": "boolean"
        +}
  4. 3 tool updatesv0.1.17
    • Addedrego_playground_share
    • Changedrego_test4 fields changed
      • addedInput schema / properties / bundle
        Added value: +{
        +  "description": "Load paths as OPA bundle roots (`--bundle`). Required when testing policies structured as bundles with a `manifest.json` at the root. Not needed for plain policy directories.",
        +  "type": "boolean"
        +}
      • addedInput schema / properties / count
        Added value: +{
        +  "description": "Number of times to repeat each test (`--count N`). Default is 1. Useful for measuring repeatability or catching flaky tests under load.",
        +  "minimum": 1,
        +  "type": "integer"
        +}
      • addedInput schema / properties / ignorePatterns
        Added value: +{
        +  "description": "Glob patterns for files to exclude from the test run (`--ignore <pattern>`). Pass one pattern per array element. Useful for excluding generated or fixture files that contain no tests (e.g. `[\"*_generated.rego\", \"fixtures/**\"]`).",
        +  "items": {
        +    "type": "string"
        +  },
        +  "type": "array"
        +}
      • addedInput schema / properties / timeout
        Added value: +{
        +  "description": "Per-test timeout as a Go duration string, e.g. `\"30s\"` or `\"2m\"` (`--timeout`). OPA's default is 5s. Increase for tests that load large policy sets or call slow built-ins.",
        +  "type": "string"
        +}
    • Addedrego_test_multiroot
  5. 1 tool updatev0.1.14
    • Addedrego_explain_undefined
  6. 45 tool updatesv0.1.13
    • Addedconftest_pull
    • Addedconftest_push
    • Addedconftest_test
    • Addedconftest_verify
    • Addedmcp_server_info
    • Addedopa_bundle_build
    • Addedopa_bundle_sign
    • Addedopa_bundle_verify
    • Addedopa_compile_query
    • Addedopa_config
    • Addedopa_delete_data
    • Addedopa_delete_policy
    • Addedopa_exec
    • Addedopa_get_data
    • Addedopa_get_policy
    • Addedopa_health
    • Addedopa_list_policies
    • Addedopa_patch_data
    • Addedopa_put_data
    • Addedopa_put_policy
    • Addedopa_query_decision
    • Addedopa_status
    • Addedrego_bench
    • Addedrego_capabilities
    • Addedrego_compile_query
    • Addedrego_coverage_gaps
    • Addedrego_deps
    • Addedrego_describe_policy
    • Addedrego_eval
    • Addedrego_eval_with_coverage
    • Addedrego_eval_with_explain
    • Addedrego_eval_with_profile
    • Addedrego_explain_decision
    • Addedrego_fix
    • Addedrego_format_write
    • Addedrego_generate_test_skeleton
    • Addedrego_infer_input_schema
    • Addedrego_inspect
    • Addedrego_migrate_v1
    • Addedrego_parse_ast
    • Addedrego_policy_diff
    • Addedrego_security_audit
    • Addedrego_suggest_fix
    • Addedrego_test
    • Addedrego_verify
  7. 4 tool updates
    • Addedrego_check
    • Addedrego_check_schema
    • Addedrego_format
    • Addedrego_lint
  8. 32 tool updatesv0.1.5
    • Removedopa_bundle_build
    • Removedopa_bundle_sign
    • Removedopa_compile_query
    • Removedopa_config
    • Removedopa_delete_policy
    • Removedopa_get_data
    • Removedopa_get_policy
    • Removedopa_health
    • Removedopa_list_policies
    • Removedopa_patch_data
    • Removedopa_put_data
    • Removedopa_put_policy
    • Removedopa_query_decision
    • Removedopa_status
    • Removedrego_bench
    • Removedrego_capabilities
    • Removedrego_check
    • Removedrego_compile_query
    • Removedrego_deps
    • Removedrego_describe_policy
    • Removedrego_eval
    • Removedrego_eval_with_coverage
    • Removedrego_eval_with_explain
    • Removedrego_eval_with_profile
    • Removedrego_explain_decision
    • Removedrego_format
    • Removedrego_generate_test_skeleton
    • Removedrego_inspect
    • Removedrego_lint
    • Removedrego_parse_ast
    • Removedrego_suggest_fix
    • Removedrego_test
  9. 32 tool updatesv0.1.2
    • Addedopa_bundle_build
    • Addedopa_bundle_sign
    • Addedopa_compile_query
    • Addedopa_config
    • Addedopa_delete_policy
    • Addedopa_get_data
    • Addedopa_get_policy
    • Addedopa_health
    • Addedopa_list_policies
    • Addedopa_patch_data
    • Addedopa_put_data
    • Addedopa_put_policy
    • Addedopa_query_decision
    • Addedopa_status
    • Addedrego_bench
    • Addedrego_capabilities
    • Addedrego_check
    • Addedrego_compile_query
    • Addedrego_deps
    • Addedrego_describe_policy
    • Addedrego_eval
    • Addedrego_eval_with_coverage
    • Addedrego_eval_with_explain
    • Addedrego_eval_with_profile
    • Addedrego_explain_decision
    • Addedrego_format
    • Addedrego_generate_test_skeleton
    • Addedrego_inspect
    • Addedrego_lint
    • Addedrego_parse_ast
    • Addedrego_suggest_fix
    • Addedrego_test
  10. 32 tool updatesv0.1.1
    • Removedopa_bundle_build
    • Removedopa_bundle_sign
    • Removedopa_compile_query
    • Removedopa_config
    • Removedopa_delete_policy
    • Removedopa_get_data
    • Removedopa_get_policy
    • Removedopa_health
    • Removedopa_list_policies
    • Removedopa_patch_data
    • Removedopa_put_data
    • Removedopa_put_policy
    • Removedopa_query_decision
    • Removedopa_status
    • Removedrego_bench
    • Removedrego_capabilities
    • Removedrego_check
    • Removedrego_compile_query
    • Removedrego_deps
    • Removedrego_describe_policy
    • Removedrego_eval
    • Removedrego_eval_with_coverage
    • Removedrego_eval_with_explain
    • Removedrego_eval_with_profile
    • Removedrego_explain_decision
    • Removedrego_format
    • Removedrego_generate_test_skeleton
    • Removedrego_inspect
    • Removedrego_lint
    • Removedrego_parse_ast
    • Removedrego_suggest_fix
    • Removedrego_test
  11. 32 tool updatesv0.1.0
    • First observedopa_bundle_build
    • First observedopa_bundle_sign
    • First observedopa_compile_query
    • First observedopa_config
    • First observedopa_delete_policy
    • First observedopa_get_data
    • First observedopa_get_policy
    • First observedopa_health
    • First observedopa_list_policies
    • First observedopa_patch_data
    • First observedopa_put_data
    • First observedopa_put_policy
    • First observedopa_query_decision
    • First observedopa_status
    • First observedrego_bench
    • First observedrego_capabilities
    • First observedrego_check
    • First observedrego_compile_query
    • First observedrego_deps
    • First observedrego_describe_policy
    • First observedrego_eval
    • First observedrego_eval_with_coverage
    • First observedrego_eval_with_explain
    • First observedrego_eval_with_profile
    • First observedrego_explain_decision
    • First observedrego_format
    • First observedrego_generate_test_skeleton
    • First observedrego_inspect
    • First observedrego_lint
    • First observedrego_parse_ast
    • First observedrego_suggest_fix
    • First observedrego_test

TDQS

A3.6/5.0
Disambiguation3/5

The domain prefixes (rego_, opa_, conftest_) help separate broad areas, and descriptions are detailed. However, many tools are near-neighbors: rego_eval variants, rego_explain_decision vs. rego_eval_with_explain, rego_format vs. rego_format_write vs. rego_fix, and opa_status vs. opa_config returning the same underlying document. An agent can usually disambiguate with careful reading, but misselection risk is notable.

Naming Consistency3/5

All names are snake_case and consistently prefixed by rego_, opa_, or conftest_, which is readable. However, the verb/noun ordering is mixed: rego_parse_ast and opa_delete_policy are verb-first, while opa_bundle_build and rego_playground_share are noun-first, and several tools are bare nouns like rego_capabilities, opa_status, and opa_config. The convention is predictable at the prefix level but not a uniform verb_noun pattern.

Tool Count2/5

52 tools is a very heavy MCP surface, well above the range where an agent can quickly select the right tool. Many tools are variants of the same core operation, such as the multiple rego_eval_* forms, the format/fix/write cluster, and the status/config pair. The broad OPA/Conftest scope partially justifies the size, but the count still feels excessive and burdensome.

Completeness4/5

The toolset is remarkably complete for the OPA/Rego ecosystem: authoring, checking, linting, testing, benchmarking, schema inference, policy/data CRUD against a server, bundle build/sign/verify, and conftest integration are all present. Minor gaps exist, such as no explicit remote bundle upload/activation workflow, but most core workflows have no dead ends.

Maintenance

ActivityActive
ResponsivenessNo issues

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