tool-discovery

tool-discovery is a skill for Claude Code, Codex from tallclub/matimo. It costs 33 tokens per session (3,050 once invoked), scanned A, original, MIT.

A guide for finding and managing tools available to an agent, including built-in, provider-specific, and user-created tools.

In plain words
What is it for?
Use it to list tools in a directory, search by criteria, group tools by risk, and understand draft, approved, and rejected states.
Why use it?
It removes the need to guess where tools come from or what state they are in. It also explains how to find user-created tools and assess their status.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to list tools in a directory, search by criteria, group tools by risk, and understand draft, approved, and rejected states.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tallclub/matimo/tool-discovery
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 tallclub/matimo --skill tool-discovery
Clone the repo
git clone --depth 1 https://github.com/tallclub/matimo

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-discovery

README.md
[![agentmods](https://agentmods.dev/badge/skills/tallclub/matimo/tool-discovery.svg)](https://agentmods.dev/skills/tallclub/matimo/tool-discovery)
Your own site
<a href="https://agentmods.dev/skills/tallclub/matimo/tool-discovery"><img src="https://agentmods.dev/badge/skills/tallclub/matimo/tool-discovery.svg" alt="Measured on agentmods" height="20"></a>
Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,050 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 4 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Data Exfiltration · line 168
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
  • medium Data Exfiltration · line 206
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
  • medium Excessive Agency · line 175
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
  • medium Data Exfiltration · line 187
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
How audits are shown
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 $0.00033 $0.03050
Opus 5 $0.00016 $0.01525
Sonnet 5 $0.00007 $0.00610
Haiku 4.5 $0.00003 $0.00305

Measured 8d ago against content hash 9ba996e3737e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

tool-discovery 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 8d 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.

typescript/packages/core/skills/tool-discovery/SKILL.md · 499 lines

How it starts

The opening of the file, as written. The whole thing — 499 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tool Discovery: Finding and Managing Tools

This skill teaches you how to discover, search, and manage Matimo tools that are available in your system.

Overview: Tool Sources

Three sources of tools:

  1. Core/Built-in Tools — Shipped with Matimo SDK

    • matimo_create_tool, matimo_validate_tool, matimo_doctor, etc.
    • Read-only, always available
    • Used by agents to manage tool lifecycle
  2. Provider Tools — Application-specific tools from packages

    • Slack tools, GitHub tools, AWS tools, etc.
    • Defined in packages/{provider}/tools/
    • Available after initialization with toolPaths
  3. User-Created Tools — Dynamically created by agents

    • Stored in target_dir (usually temp directory)
    • Status: draft, approved, rejected
    • Discovered via matimo_list_user_tools

Meta-Tool: matimo_list_user_tools

Lists all tools created by agents in a specific directory.

Input:  { target_dir: "/path/to/tools" }
Output: { tools: [...] status: "success" }

Basic Usage

Call: matimo_list_user_tools(target_dir="/tmp/my-tools")

Response:
{
  "tools": [
    {
      "name": "weather_fetch",
      "version": "1.0.0",
      "description": "Get current weather for a city",
      "status": "approved",
      "riskLevel": "LOW",
      "createdAt": "2026-03-17T10:30:00Z",
      "executionType": "http",
      "requiresApproval": false
    },
    {
      "name": "file_reader",
      "version": "1.0.0",
      "description": "Read files from filesystem",
      "status": "rejected",
      "riskLevel": "CRITICAL",
      "reason": "Command tools are blocked by policy",
      "createdAt": "2026-03-17T10:31:00Z",
      "executionType": "command",
      "requiresApproval": true
    }
  ],
  "summary": {
    "total": 2,
    "approved": 1,
    "rejected": 1,
    "draft": 0
  }
}

Understanding Tool Status

Status: approved

Tool has been validated and approved by human operator. Ready to use.

Indicators:
- ✅ Created with matimo_create_tool
- ✅ Passed matimo_doctor validation
- ✅ Human approved via matimo_review
- ✅ Registry reloaded via matimo_reload_tools
- ✅ Executable via matimo.execute()

Read the full file on GitHub · 499 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. 8d ago First seen · 499 lines · 33 tokens per session scan A 9ba996e3737e

Subscribe to this mod's changes

tool-discovery is a skill published in the GitHub repository tallclub/matimo (11 stars, last pushed 4d ago), licensed MIT. It adds 33 tokens to every session and 3,050 once invoked, about $0.0002 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 2026-08-30.

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