tool-description-check

tool-description-check is a skill for Claude Code, Codex from Grinv/mal-mcp. It costs 74 tokens per session (3,889 once invoked), scanned A, original, MIT.

A review checklist for descriptions of MCP tools and their input fields. MCP is a standard way for AI assistants to call external tools and services.

In plain words
What is it for?
Use it to check a new or edited tool description against live behavior, compare it with related tools, and assess its clarity and usefulness.
Why use it?
It helps catch unclear, unsupported, contradictory, or incomplete descriptions before they mislead the assistant or users.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/grinv/mal-mcp/tool-description-check
Any agent
npx skills add Grinv/mal-mcp --skill tool-description-check
Clone the repo
git clone --depth 1 https://github.com/Grinv/mal-mcp

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for tool-description-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/grinv/mal-mcp/tool-description-check.svg)](https://agentmods.dev/skills/grinv/mal-mcp/tool-description-check)
Your own site
<a href="https://agentmods.dev/skills/grinv/mal-mcp/tool-description-check"><img src="https://agentmods.dev/badge/skills/grinv/mal-mcp/tool-description-check.svg" alt="Measured on agentmods" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,889 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00074 $0.03889
Opus 5 $0.00037 $0.01945
Sonnet 5 $0.00015 $0.00778
Haiku 4.5 $0.00007 $0.00389

Measured 4d ago against content hash eca9a63dc365, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tool-description-check scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/tool-description-check/SKILL.md · 270 lines

How it starts

The opening of the file, as written. The whole thing — 270 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tool descriptions: what to check before committing

Published research on this exact failure mode: Glama's TDQS methodology found 97% of 856 tools across 103 real MCP servers have a description defect — 56% don't clearly state what the tool does, 89% don't say when to use it. Separately, "From Docs to Descriptions" measured that strong descriptions get 260% more selection in competitive scenarios and lift task success ~6 points. Bad descriptions aren't a hypothetical risk; they're the median case. This server is scored on the same rubric at glama.ai/mcp/servers/Grinv/mal-mcp/score (re-analyzed on Glama's own schedule, not on push — treat this as a manual pre-commit check, not something to verify live after every edit).

TDQS dimension Weight Question
Purpose Clarity 25% Does the description state what the tool does?
Usage Guidelines 20% Does it say when to use this tool vs. alternatives?
Behavioral Transparency 20% Does it disclose behavior beyond what annotations already provide?
Parameter Semantics 15% Does it add meaning beyond what the input schema provides?
Conciseness & Structure 10% Is it appropriately sized and front-loaded?
Contextual Completeness 10% Given the tool's complexity, is the description complete enough?

Usage Guidelines and Behavioral Transparency carry the most weight after Purpose — double-check those two first on any new or edited tool.

Two rules that override everything below

  1. No unverified claims. Every behavioral statement in a description — not just "the schema allows this input," which is self-evidently true, but "here's what happens when you send it" — must be backed by one of:
    • an existing docs/api-references.md "verified live" entry, cited by reference instead of re-asserted from memory (e.g. the "no-match search doesn't return empty" note for the official-API fallback, or the num_episodes_watched/num_watched_episodes read/write field-name mismatch — both already verified there);
    • a fresh live call against Tenrai/the official API made during this review, with the actual response observed;
    • direct reading of the exact function implementing the behavior, when it's deterministic code logic rather than an upstream API's quirk (e.g. #updateStatus in clients/mal.ts sends only the fields passed in, confirming update_my_anime_status's "fields you omit are left unchanged" claim).

Read the full file on GitHub · 270 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 270 lines · 74 tokens per session scan A eca9a63dc365

Subscribe to this mod's changes

tool-description-check is a skill published in the GitHub repository Grinv/mal-mcp (2 stars, last pushed 11d ago), licensed MIT. It adds 74 tokens to every session and 3,889 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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