tool-defs-analysis

tool-defs-analysis is a skill for Claude Code from wallieinformal201/pentest-mcp-server. It costs 132 tokens per session (2,858 once invoked), scanned A, original, Apache-2.0.

A read-only review of the written definitions for MCP tools, resources, and prompts. MCP is a format that lets an AI assistant use external tools and data.

In plain words
What is it for?
Use it to review every definition file in an existing MCP project. It checks the language the assistant relies on to choose tools, fill in inputs, understand outputs, and recover from errors.
Why use it?
It finds wording that could confuse an AI assistant, such as hidden implementation details, unclear defaults, missing recovery guidance, or inconsistent descriptions.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the @cyanheads/pentest-mcp-server plugin — 31 skills shipped together

Good fit Use it to review every definition file in an existing MCP project. It checks the language the assistant relies on to choose tools, fill in inputs, understand outputs, and recover from errors.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/wallieinformal201/pentest-mcp-server/tool-defs-analysis
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.

Any agent
npx skills add wallieinformal201/pentest-mcp-server --skill tool-defs-analysis
Clone the repo
git clone --depth 1 https://github.com/wallieinformal201/pentest-mcp-server

Made for: Claude Code.

Or install @cyanheads/pentest-mcp-server, the plugin that ships this one along with the rest of its 31 skills.

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-defs-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/wallieinformal201/pentest-mcp-server/tool-defs-analysis/github.svg)](https://agentmods.dev/skills/wallieinformal201/pentest-mcp-server/tool-defs-analysis)
Your own site
<a href="https://agentmods.dev/skills/wallieinformal201/pentest-mcp-server/tool-defs-analysis"><img src="https://agentmods.dev/badge/skills/wallieinformal201/pentest-mcp-server/tool-defs-analysis/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for tool-defs-analysis

Your own site · 80×15
<a href="https://agentmods.dev/skills/wallieinformal201/pentest-mcp-server/tool-defs-analysis"><img src="https://agentmods.dev/badge/skills/wallieinformal201/pentest-mcp-server/tool-defs-analysis.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 132 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,858 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00132 $0.02858
Opus 5 $0.00066 $0.01429
Sonnet 5 $0.00026 $0.00572
Haiku 4.5 $0.00013 $0.00286

Measured 12d ago against content hash 9de6381cd974, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

tool-defs-analysis 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 12d 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.

skills/tool-defs-analysis/SKILL.md · 229 lines

How it starts

The opening of the file, as written. The whole thing — 229 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context

Every string in a tool/resource/prompt definition is part of an LLM-facing API contract. The model reads the description, every parameter .describe(), the output schema, the recovery hints — and decides what to call and how. Definition language drifts: an internal mapping leaks into a parameter doc during a fix, a self-referential output description survives a refactor, a default that suited the developer at scaffold time stays after the typical call shape changes.

This skill is the review-time pass for that drift. Read each definition the way a mid-tier model with no project context would — can it pick the tool, fill the fields, and recover from errors using only the rendered schema?

Skill Lens
design-mcp-server Authoring rules at write-time
field-test Behavior testing + a narrow 3-category leak audit
security-pass Injection, scopes, input sinks
tool-defs-analysis (this) LLM-facing language across the existing surface

field-test already audits descriptions for implementation leaks, meta-coaching, and consumer-aware phrasing during its catalog step — that's a fast shallow pass alongside live tool calls. This skill is the deeper review: 12 categories, every field, every recovery hint, every default value, with file:line citations.

Read-only. This skill produces a report; the maintainer applies fixes. While running it, do not run git, do not stage or commit, do not update the changelog, do not run devcheck, do not invoke wrapup or release workflows. Fixes flow through the normal authoring path (edit the definition, then re-run this skill if you want to verify).

When to Use

  • After a polish session or refactor that touched definitions
  • Before a release, alongside polish-docs-meta and security-pass
  • When the user says "review my tool definitions", "audit descriptions", "are my tool descriptions any good"
  • After scaffolding a new server but before it ships

Skip during initial authoring — add-tool and design-mcp-server cover that. Skip diff-only review — read each file in full so drift across the whole definition surfaces.

Read the full file on GitHub · 229 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. 12d ago First seen · 229 lines · 132 tokens per session scan A 9de6381cd974

Subscribe to this mod's changes

tool-defs-analysis is a skill published in the GitHub repository wallieinformal201/pentest-mcp-server (2 stars, last pushed today), licensed Apache-2.0. It adds 132 tokens to every session and 2,858 once invoked, about $0.0007 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.