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vllm-ops-mcp

vllm-ops-mcp

License: MIT tests CI

Read-only ops/health MCP server for a local, WSL2/systemd-managed vLLM server -- liveness vs. real-completion health tiers, GPU/VRAM status, systemd service status, and live serve-flag introspection. Built to the same standard as mcp-factory and desktop-mcp, and other local tooling in this operator's portfolio: own pyproject, own fastmcp server, honest README, real test suite, no product code before a spec was confirmed.

This is not a container-lifecycle manager. It assumes vLLM already runs as a bare-metal systemd unit inside WSL2 (this operator's actual setup -- see vllm-autostart), not inside Docker/Podman.

Quickstart

// ~/.claude.json (or any MCP-host stdio client config)
{
  "mcpServers": {
    "vllm-ops-mcp": {
      "type": "stdio",
      "command": "C:\\Users\\<you>\\projects\\vllm-ops-mcp\\.venv\\Scripts\\python.exe",
      "args": ["C:\\Users\\<you>\\projects\\vllm-ops-mcp\\run_server.py"]
    }
  }
}

Related MCP server: infra-mcp

Tools (Phase 1 -- all read-only, no gating required beyond a throughput cap)

Tool

What it does

What it can't do

check_health(deep: bool = False)

deep=False: GET /v1/models liveness check (same signal as llm_router.LocalLLM.is_healthy()). deep=True: additionally fires one minimal real /v1/chat/completions call (mirrors check-vllm.cmd's two-stage probe) to confirm the server actually generates, not just reports a model loaded.

Cannot fix a degraded server -- reports ground truth only. deep=True is rate-limited (default 20/min, see below).

list_models

/v1/models passthrough.

No detail beyond what vLLM's API itself exposes.

test_completion(prompt, max_tokens=16)

On-demand real completion with a caller-supplied prompt, for manual sanity checks.

Rate-limited (same bucket as check_health(deep=True)); refuses if the liveness check fails first (no point firing a completion at a server that isn't even listening). max_tokens is clamped server-side to 1024 (config.MAX_TEST_COMPLETION_TOKENS) and the prompt is capped at 8000 chars (config.MAX_TEST_COMPLETION_PROMPT_CHARS, oversized prompts are rejected, not truncated) -- the rate limiter only bounds call frequency, not the cost of a single call.

get_gpu_status

nvidia-smi wrapper: per-GPU VRAM used/total + utilization%, plus per-process VRAM via --query-compute-apps.

Per-process VRAM attribution does not work on this operator's actual WSL2 setup -- live-verified empty even while the vLLM process holds 13.7GB (see Limitations). Treat processes as best-effort/often-empty, not a reliable per-PID breakdown.

get_service_status

systemctl show <unit> -p ... (structured property output, not free-text parsing) via wsl -d <distro> from the Windows host, or native systemctl if this server itself runs inside WSL2/Linux. Returns load/active/sub state, restart count, main PID, last-active timestamp.

Read-only -- cannot start/stop/restart the unit. No computed uptime duration (deliberately -- see Limitations, clock-discipline note).

get_serve_config

Read-only launch-flag introspection. Prefers the LIVE process's actual argv (/proc/<pid>/cmdline of the systemd unit's MainPID -- ground truth of what's running right now), falling back to the static exec script (local mirror via VLLM_OPS_MCP_SERVE_CONFIG_PATH, else a live cat of the WSL-side exec script) only when the process isn't up.

vLLM doesn't expose its own launch flags over the API, so this never queries the server itself -- it's always shelling out. Exec-script fallback parsing is best-effort shell-text parsing (less precise than the live-argv path).

Future extension: restart_service (Phase 2, not built)

Deliberately not implemented in this release. Per the spec: vLLM is shared infra other bots/tools depend on (options-bot, qwen_cli.py callers, DeerFlow fallback), so a restart tool needs its own gating design (off by default, VLLM_OPS_MCP_ENABLE_RESTART=1, refuse to touch a healthy instance unless force=True, rate-capped) before it ships -- not retrofitted onto a read-only MVP. Tracked as a v2 idea, not a current capability. If built, it should wrap run-vllm.cmd's exact recipe (systemctl start vllm only, never blind stop/restart) rather than reinvent it.

The differentiator: probe HTTP, not the listener

Every health signal in this server comes from an actual HTTP request to the OpenAI-compatible API (urllib.request, not a socket/connect check). This is deliberate, not incidental: Get-NetTCPConnection and other listener-based checks miss WSL2-mirrored-networking-relayed ports entirely -- a genuinely healthy 127.0.0.1:8000 can be invisible to a listener probe run from the Windows host. check-vllm.cmd already embodies this lesson; this server generalizes it into two tiers (liveness vs. real generation) that nothing else in this operator's fleet exposes as MCP tools.

Security

Read this before you register vllm-ops-mcp. Honesty about blast radius is the point.

  • This server shells out to nvidia-smi, systemctl (via wsl -d), and reads /proc/<pid>/cmdline. All six tools are read-only -- nothing here starts, stops, restarts, or kills a process, and no tool accepts an argument that gets passed to a shell unescaped (unit/distro names come from server-side config, not caller input; shlex.quote wraps the one caller-adjacent path that does reach a shell string, the unit name in systemctl show).

  • check_health(deep=True) and test_completion fire a real inference call against a shared GPU server. Rate-limited (default 20 calls/min, VLLM_OPS_MCP_DEEP_RATE_LIMIT_PER_MIN) specifically because this vLLM instance is shared infra other bots/tools depend on -- a caller hammering this MCP could starve or slow other consumers even though every call individually looks "read-only."

  • get_serve_config's live-process path reads /proc/<pid>/cmdline, which can include secrets if any were ever passed as CLI flags (none are, in this operator's actual setup -- the model path and flags are all non-secret; auth, if any, is environment-injected inside the exec script, not passed as an argv flag). Defense-in-depth: any argv entry whose preceding flag name matches a known-sensitive pattern (token, key, secret, password, passwd, credential -- config. SENSITIVE_ARGV_FLAG_PATTERNS) has its value redacted to [REDACTED] before being returned, in both the structured argv/flags fields and raw_text; the flag name itself is left visible so the shape is still diagnosable. This applies across all three sources (live_process, exec_script, local_config_mirror).

  • No tool has any write/mutate capability in this release. There is no env var that turns one on -- restart_service doesn't exist in this codebase yet (see Future extension above), so there's nothing to accidentally enable.

Honest-capabilities table

Claim

Implementation

Verified by

Liveness health tier (/v1/models)

vllm_ops_mcp/probes.py::_probe_models, check_health

tests/test_probes.py::TestCheckHealthLiveness; live: tests/test_live_smoke.py::test_live_check_health_liveness

Deep/real-completion health tier

vllm_ops_mcp/probes.py::_probe_completion, check_health(deep=True)

tests/test_probes.py::TestCheckHealthDeep; live: test_live_check_health_deep

Model list passthrough

probes.py::list_models

tests/test_probes.py::TestListModels; live: test_live_list_models

On-demand completion sanity check

probes.py::test_completion

tests/test_probes.py::TestTestCompletion; live: test_live_test_completion

GPU/VRAM status via nvidia-smi

probes.py::get_gpu_status

tests/test_probes.py::TestGetGpuStatus; live: test_live_get_gpu_status

Per-process VRAM attribution

probes.py::get_gpu_status (--query-compute-apps)

Unit-tested with a mocked non-empty response; live-verified to return EMPTY on this operator's actual WSL2 setup -- see Limitations

systemd unit status via structured systemctl show

probes.py::get_service_status

tests/test_probes.py::TestGetServiceStatus; live: test_live_get_service_status

Live-process launch-flag introspection via /proc/<pid>/cmdline

probes.py::get_serve_config, parse_launch_flags

tests/test_probes.py::TestGetServeConfig, TestParseLaunchFlags; live: test_live_get_serve_config -- live-confirmed it recovers flags (--enable-auto-tool-choice --tool-call-parser qwen3_xml) that were not in this repo's own grounding spec, proving the live-argv approach beats trusting a static doc

Exec-script fallback when the unit is down

probes.py::get_serve_config, _parse_exec_script_text

tests/test_probes.py::TestGetServeConfig::test_falls_back_to_exec_script_when_service_down

Local config-mirror override path

probes.py::get_serve_config + config.serve_config_override_path

tests/test_probes.py::TestGetServeConfig::test_uses_local_override_file, test_override_file_missing_reports_error

Sensitive-flag-value redaction in get_serve_config

probes.py::redact_argv, redact_raw_text, config.SENSITIVE_ARGV_FLAG_PATTERNS

tests/test_probes.py::TestGetServeConfig::test_live_process_redacts_sensitive_flag_values, test_exec_script_raw_text_redacts_sensitive_flag_values, test_local_override_file_redacts_sensitive_flag_values

Deep-inference rate limiting (shared-infra protection)

config.py::TokenBucket, DeepRateLimiter, check_deep_rate_limit

tests/test_config.py::TestTokenBucket, TestDeepRateLimiter

WSL-vs-native shell-out abstraction

probes.py::_shell_args, config.runs_in_wsl

tests/test_config.py::TestRunsInWsl; tests/test_probes.py::TestGetServiceStatus::test_uses_wsl_prefix_on_windows, test_no_wsl_prefix_when_native

All 6 tools registered, no Phase-2 tool present

vllm_ops_mcp/server.py

tests/test_server.py

Limitations (read before relying on this)

  • Per-process VRAM attribution is unreliable under this operator's actual WSL2 GPU-passthrough config. get_gpu_status's live smoke test (real nvidia-smi.exe against the real running vLLM process) returned an empty processes list even though the same call's gpus[0]. memory_used_mib correctly showed 13.7GB in use by that process. This is a documented nvidia-smi --query-compute-apps limitation under some WSL2/passthrough configurations, not a bug in this server's parsing -- the tool reports the empty result honestly (ok: true, processes: []) rather than fabricating attribution. Don't rely on processes for VRAM-overshoot root-causing on this setup; gpus[].memory_used_mib is the reliable signal.

  • No computed service uptime. get_service_status returns the raw ActiveEnterTimestamp string from systemctl (already timezone-labeled, e.g. MDT) rather than computing an elapsed duration server-side -- deliberately, per this operator's own clock-discipline rule (never state an elapsed/ETA time from estimation; artifact timestamps are often UTC while local is UTC-6/-7). Compute the delta at the call site if you need it, with an explicit timezone conversion.

  • get_serve_config's exec-script fallback is best-effort shell-text parsing, not an exact argv array -- it handles \ line continuations and basic quoting via shlex.split, but a sufficiently unusual exec script could parse incorrectly. The live-process path (/proc/<pid>/ cmdline) does not have this limitation (it's the kernel's exact argv, null-separated) and is always preferred when the unit is up.

  • WSL2-specific by default, but the seam is explicit. get_service_status and get_serve_config's live-process path assume this server runs on the Windows host and shells into WSL2 via wsl -d <distro>. Set VLLM_OPS_MCP_RUNS_IN_WSL=1 if this server process itself runs inside WSL2/Linux natively (native systemctl/cat, no wsl -d hop) -- both paths are unit-tested (TestGetServiceStatus::test_uses_wsl_prefix_on_windows / test_no_wsl_prefix_when_native), but only the Windows-host path has been live-verified against this operator's actual setup.

  • Single vLLM instance, single GPU, this operator's setup. No multi-instance/multi-GPU aggregation; get_gpu_status returns whatever nvidia-smi --query-gpu enumerates, which is every GPU visible to the process, not scoped to "the GPU vLLM is using" if more than one exists.

  • No lifecycle control whatsoever in this release. See "Future extension" above -- this is intentional, not an oversight.

Env vars

Var

Effect

Default

VLLM_OPS_MCP_BASE_URL

OpenAI-compatible base URL

http://127.0.0.1:8000/v1 (explicit 127.0.0.1, not localhost -- see qwen_cli.py's IPv6-hang footgun note)

VLLM_OPS_MCP_MODEL

served-model-name, used in completion payloads

qwen3-14b

VLLM_OPS_MCP_WSL_DISTRO

WSL distro hosting vLLM

Ubuntu-22.04

VLLM_OPS_MCP_SERVICE_UNIT

systemd unit name

vllm

VLLM_OPS_MCP_EXEC_SCRIPT_PATH

WSL-side path to the serve exec script (fallback source)

~/vllm-systemd-exec.sh

VLLM_OPS_MCP_SERVE_CONFIG_PATH

local file mirror of the exec script; if set, get_serve_config reads it directly instead of shelling into WSL as a fallback source

unset

VLLM_OPS_MCP_NVIDIA_SMI_PATH

nvidia-smi binary override

nvidia-smi (Windows host) / nvidia-smi.exe (native WSL2)

VLLM_OPS_MCP_RUNS_IN_WSL

1 if this server process itself runs inside WSL2/Linux (skips the wsl -d hop)

auto-detected via sys.platform

VLLM_OPS_MCP_DEEP_RATE_LIMIT_PER_MIN

cap on check_health(deep=True) + test_completion calls/min

20

VLLM_OPS_MCP_LIVE

1 to run real-infra smoke tests (see Testing)

unset (skip)

Usage examples

// A tool call from the MCP host, illustrative -- not a shell command.
{"tool": "check_health", "arguments": {"deep": true}}
// -> {"ok": true, "status": "up", "tier": "deep", "model_id": "qwen3-14b",
//     "latency_ms": 32.0, "completion_s": 0.218, "error": ""}

{"tool": "get_serve_config", "arguments": {}}
// -> {"ok": true, "source": "live_process", "pid": 5645,
//     "flags": {"model": "Qwen/Qwen3-14B-AWQ", "served_model_name": "qwen3-14b",
//               "port": "8000", "max_model_len": "8192",
//               "gpu_memory_utilization": "0.72", "max_num_seqs": "8",
//               "enable_auto_tool_choice": true, "tool_call_parser": "qwen3_xml", ...}}

// rate limit exceeded (21st deep call within a minute):
{"tool": "test_completion", "arguments": {"prompt": "hi"}}
// -> {"ok": false, "error": {"type": "rate_limited", "group": "deep_inference",
//     "tool": "test_completion", "limit_per_min": 20, "retry_after_s": 4.87}}

Testing

CI (.github/workflows/ci.yml) runs this suite on every push/PR (ubuntu-latest -- the unit suite mocks HTTP/subprocess, no live server/GPU/WSL required) and fails the build if the Tests badge above drifts from what the suite actually reports -- see scripts/check_readme_counts.py.

# unit suite (mocked HTTP/subprocess, no live server/GPU/WSL required)
.venv\Scripts\python.exe -m pytest -q
# -> 95 passed, 7 skipped

# handshake check -- prints every registered tool name
.venv\Scripts\python.exe scripts\list_tools.py

# real-infra smokes (real vLLM completion, real nvidia-smi, real systemctl
# via WSL, real /proc/<pid>/cmdline read) -- read-only, safe to run anytime
# vLLM is up
VLLM_OPS_MCP_LIVE=1 .venv\Scripts\python.exe -m pytest -v -m live
# -> 7 passed (all live, against the actual running qwen3-14b instance)

Install

python -m venv .venv
.venv\Scripts\python.exe -m pip install -r requirements.txt

Registered in ~/.claude.json as vllm-ops-mcp (stdio, own .venv, no env overrides needed for this operator's default setup).

Commercial support

Maintained by Jaimen Bell. For production MCP integrations, custom servers, or agent-reliability work, see jaimenbell.dev.

Building your own MCP server? The MCP Starter Kit has templates, a build playbook, and packaging war-stories from shipping this one.

mcp-name: io.github.jaimenbell/vllm-ops-mcp

Available Tools

6 tools
check_healthA

Two-stage health probe for the local vLLM server, mirroring check-vllm.cmd. deep=False (default): GET /v1/models liveness check only. deep=True: additionally fires one minimal real /v1/chat/completions call to confirm the server actually generates text, not just reports a model loaded (rate-limited -- this consumes real GPU inference cycles on shared infra). Returns {ok, status: up|degraded|down, tier, model_id, latency_ms, completion_s, error}.

ParametersJSON Schema
NameRequiredDescriptionDefault
deepNo

Output Schema

ParametersJSON Schema
NameRequiredDescription

No output parameters

TDQS

A4.8/5.0
Behavior5/5

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

With no annotations, the description carries the full burden and does so excellently. It discloses the two-stage behavior, the exact HTTP calls, the side effect of GPU consumption, and the complete return envelope. This is unusually transparent for a health check.

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. The description efficiently covers purpose, parameter semantics, behavioral caveats, and return value without redundancy. It is front-loaded with the main verb and resource, then details.

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 simplicity (one parameter, output schema present), the description is complete. It explains the two modes, the side effects, and the return structure. No important aspect is left unexplained.

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?

The schema only provides a bare 'deep' boolean with no description. The description fully explains the parameter's meaning, default, and the behavioral difference between true and false, adding substantial meaning 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 opens with a specific verb+resource: 'Two-stage health probe for the local vLLM server.' It clearly distinguishes this from siblings like list_models or test_completion by framing it as a health check, not a utility for listing or textual generation.

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 deep=False (liveness check) versus deep=True (verifying actual text generation) and warns that deep=True is rate-limited and consumes GPU cycles. However, it does not explicitly name sibling alternatives or state when not to use this tool in favor of another.

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

get_gpu_statusA

nvidia-smi wrapper: per-GPU VRAM used/total and utilization%, plus per-process VRAM usage (to catch VRAM-overshoot). Read-only.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription

No output parameters

TDQS

A4.2/5.0
Behavior4/5

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

With no annotations provided, the description carries the burden of behavioral disclosure. It explicitly states 'Read-only,' which is a key safety trait, and explains the per-process VRAM tracking rationale. It adds context beyond the tool name, though it omits potential failure modes (e.g., nvidia-smi not available).

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, tightly-worded sentence that front-loads the essential information ('nvidia-smi wrapper') and efficiently includes all necessary details without waste. Every word contributes to the meaning.

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 read-only status tool with no parameters and an output schema, the description adequately covers purpose, key metrics, and safety. It does not explain return format, but the existence of an output schema makes that unnecessary. The only gap is the lack of explicit usage guidance, but this is partially covered under that dimension.

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 input schema has zero parameters, so the baseline score is 4. The description adds no parameter details (as none are needed) but clarifies what the tool reports, which is sufficient.

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 identifies the tool as an nvidia-smi wrapper for GPU status, listing specific metrics (VRAM used/total, utilization%, per-process VRAM usage). This distinguishes it from sibling tools like check_health or get_service_status, which suggest broader system or service monitoring.

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?

Usage context is implied through the phrase 'to catch VRAM-overshoot,' indicating a troubleshooting scenario. However, there is no explicit statement about when to prefer this tool over alternatives or any exclusions, leaving the guidance somewhat implicit.

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

get_serve_configA

Read-only introspection of the current vLLM launch flags. Prefers the LIVE process's real argv (/proc//cmdline of the systemd unit's MainPID) as ground truth; falls back to the static exec script if the process isn't currently up. vLLM does not expose its own launch flags over the API, so this never queries the server itself. Any argv value following a flag matching a known-sensitive pattern (token/key/secret/password/credential) is redacted before being returned.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription

No output parameters

TDQS

A4.5/5.0
Behavior5/5

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

With no annotations, the description carries full behavioral burden and excels. It discloses that it never queries the server, sources data from /proc/<pid>/cmdline with fallback to the exec script, and redacts sensitive values (token/key/secret/password/credential). This provides the agent with a complete safety and operational 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?

Three sentences, each earning its place: the first establishes purpose, the second explains the data source and fallback, the third explains redaction. It is front-loaded with the core action and avoids any redundant phrases.

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 is complete for a parameter-less tool with an output schema. It covers the source of truth, fallback logic, API interaction avoidance, and security redaction. Given no annotations and no params, there are no critical gaps in the agent's ability to invoke and interpret 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?

The tool has zero parameters, so parameter semantics are not applicable. The description does not need to compensate for schema gaps, and the baseline of 4 for parameter-less tools is appropriate. The description's detailed behavior adds context beyond the empty 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 the tool's purpose: read-only introspection of vLLM launch flags. It names the specific resource (vLLM launch flags) and action (introspection), and the use of 'read-only' distinguishes it from mutation tools. Among siblings like check_health or list_models, this is uniquely about configuration, so purpose is unambiguous.

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 explains when the tool prefers live process data over static fallback, which implies it should be used to get launch flags regardless of process state. However, it does not explicitly contrast with sibling tools or say when not to use it. There is no direct alternative mentioned, so usage guidance is implied rather than explicit.

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

get_service_statusA

systemd unit status for the vLLM service (via wsl -d <distro> -- systemctl show, or native systemctl if this server runs inside WSL2/Linux). Returns load/active/sub state, restart count, main PID, and last-active timestamp. Read-only -- never starts/stops the unit.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription

No output parameters

TDQS

A4.3/5.0
Behavior4/5

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

With no annotations, the description carries the full burden. It explicitly states 'Read-only -- never starts/stops the unit,' which is a key safety disclosure. It also details the execution context (WSL vs native systemctl) and lists the returned fields, adding transparency beyond the bare 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?

The description is two compact sentences that front-load the purpose, then add the command detail and safety note. Every phrase earns its place; the WSL/native distinction is relevant without being verbose.

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-parameter tool with an output schema, the description is fully complete. It states what the tool does, the execution environment, the specific return data, and the critical read-only constraint. Nothing essential is missing for an agent to select and invoke it 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?

The tool has zero parameters, and the description adds no parameter-specific detail beyond mentioning the distro placeholder in the underlying command. Since the schema already fully covers parameters (none), the baseline of 4 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 it reports the systemd unit status for the vLLM service, describing both the underlying command and the specific data returned. This distinguishes it from sibling tools like check_health (likely HTTP health) or get_gpu_status (hardware status).

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 use when systemd unit status is needed, but it does not explicitly contrast with alternatives or state when not to use it. No explicit when/when-not guidance is provided, though the read-only note hints at suitable contexts.

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

list_modelsA

GET /v1/models passthrough -- lists model IDs currently loaded/served.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription

No output parameters

TDQS

A4.3/5.0
Behavior4/5

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

The description explicitly states this is a GET passthrough, signaling a safe read-only operation, and clarifies that it returns currently loaded/served model IDs. With no annotations, it carries the burden well, though it omits details about error behavior or data freshness; for such a simple list tool this is acceptable.

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, front-loaded sentence with no extraneous words. It states the action and resource directly, achieving maximum efficiency.

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 tool is simple, has no parameters, and an output schema exists, so the description only needs to state its purpose. It does so clearly, and the sibling tool names provide additional context for placement.

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 schema has zero parameters, so description parameter guidance is unnecessary; the baseline for 0 params is 4. The description does clarify that the output consists of model IDs, complementing the existing output 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 uses the specific verb 'lists' and identifies the resource as 'model IDs currently loaded/served,' clearly distinguishing it from sibling tools like check_health or get_service_status. The 'GET /v1/models passthrough' prefix reinforces the operational scope without ambiguity.

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 implicitly suggests use when querying available/loaded model IDs, but provides no explicit when-to-use or when-not-to-use guidance. It does not name alternative tools, leaving usage timing to inference based on the tool's name and sibling context.

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

test_completionA

On-demand real /v1/chat/completions call with a caller-supplied prompt, for manual sanity-checking (same mechanism as check_health(deep=True) but user-controlled). Rate-limited -- consumes real GPU inference cycles on shared infra. max_tokens is clamped server-side to config.MAX_TEST_COMPLETION_TOKENS and the prompt is capped at config.MAX_TEST_COMPLETION_PROMPT_CHARS (oversized prompts are rejected) -- the rate limiter bounds call frequency, not the cost of a single call. Returns {ok, model_id, completion_s, text, error}.

ParametersJSON Schema
NameRequiredDescriptionDefault
promptYes
max_tokensNo

Output Schema

ParametersJSON Schema
NameRequiredDescription

No output parameters

TDQS

A4.9/5.0
Behavior5/5

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

With no annotations, the description fully discloses key behaviors: it is a real inference call, rate-limited, consumes GPU cycles, clamps max_tokens, caps prompt size (rejects oversized), and the rate limiter bounds frequency not per-call cost. Return shape is also given. This goes well beyond a minimal description.

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 dense sentence front-loads the core purpose and packs in all critical constraints, alternatives, and return fields without redundancy. Every clause adds value; 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?

Given an output schema exists, the description doesn't need to detail return values but does anyway. It covers purpose, usage, safety, rate limits, parameter constraints, and alternatives. For a tool with 2 params and moderate complexity, this is fully complete.

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 0%, so the description must compensate. It explains prompt as 'caller-supplied' and adds behavioral semantics for max_tokens (clamped) and prompt (capped, oversized rejected). It doesn't mention max_tokens is optional or its default, but the schema already shows default=16. This is a strong addition, though not exhaustive.

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 that the tool performs a real /v1/chat/completions call with a user-supplied prompt for manual sanity-checking. It distinguishes itself from siblings by explicitly comparing to check_health(deep=True) and noting the user-controlled nature, and from the other get/list tools which are obviously not completion calls.

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?

Provides explicit context: 'for manual sanity-checking' and directly names the alternative check_health. It also warns about rate limiting and GPU consumption, implying it should be used sparingly, and clarifies when not to rely on it (costly, rate-limited).

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. 6 tool updatesv0.1.0
    • First observedcheck_health
    • First observedget_gpu_status
    • First observedget_serve_config
    • First observedget_service_status
    • First observedlist_models
    • First observedtest_completion

TDQS

A4.4/5.0
Disambiguation4/5

Tools target distinct resources (health, models, GPU, service, config) and actions. The only potential overlap is between check_health(deep=true) and test_completion, but their purposes are clearly differentiated as health probe vs. user-driven test.

Naming Consistency5/5

All tool names follow a consistent snake_case verb_noun pattern: check_health, list_models, test_completion, get_gpu_status, get_service_status, get_serve_config. No mixed conventions or vague verbs.

Tool Count5/5

Six tools is well-scoped for a vLLM operations server. Each tool covers a distinct operational need without redundancy or bloat, fitting comfortably in the ideal 3-15 range.

Completeness4/5

The tool set covers core read-only monitoring (health, models, GPU, service, config) and testing. Minor gaps include lack of service control (start/stop/restart) and log retrieval, but these are likely intentional given the read-only nature of the service status tool.

Maintenance

ActivityMaintained
ResponsivenessNo issues

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