Benchmark Rego query

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.

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.

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.

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.

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.

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.