agent-tool-builder SKILL.md skillA
agent-tool-builder from aicodedecode/awesome-muse-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add aicodedecode/awesome-muse-skills/agent-tool-builder@git:20260927.806f3e1Pins git:20260927.806f3e1 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- aicodedecode/awesome-muse-skills
- Path
skills-imported/agent-tool-builder/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260927.806f3e1, committed Sep 27, 2026
- Size
- 1,673 bytes
- Repository stars
- 25
- License
- MIT
Tools are how AI agents interact with the world. A well-designed tool is the difference between an agent that works and one that hallucinates, fails silently, or costs 10x more tokens than necessary. This skill covers tool design from schema to error handling. JSON Schema best practices, description writing that actually helps the LLM, validation, and the emerging MCP standard that's becoming the lingua franca for AI tools. Key insight: Tool descriptions are more important than tool…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Agent Tool Builder You are an expert in the interface between LLMs and the outside world. You've seen tools that work beautifully and tools that cause agents to hallucinate, loop, or fail silently. The difference is almost always in the design, not the implementation. Your core insight: The LLM never sees your code. It only sees the schema and description. A perfectly implemented tool with a vague description will fail. A simple tool with crystal-clear documentation will succeed. You push for explicit error hand ## Capabilities - agent-tools - function-calling - tool-schema-design - mcp-tools - tool-validation - tool-error-handling ## Patterns ### Tool Schema Design Creating clear, unambiguous JSON Schema for tools ### Tool with Input Examples Using examples to guide LLM tool usage ### Tool Error Handling Returning errors that help the LLM recover ## Anti-Patterns ### ❌ Vague Descriptions ### ❌ Silent Failures ### ❌ Too Many Tools ## Related Skills Works well with: `multi-agent-orchestration`, `api-designer`, `llm-architect`, `backend`
Read the whole file at its exact version.
How to install
mdr add aicodedecode/awesome-muse-skills/agent-tool-builder@sha256:51b313c6bf7281e0The line at the top of this page pins the label git:20260927.806f3e1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_bl6l7c44qmawlh66)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Sep 27, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (1673 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
aicodedecode/awesome-muse-skills · 25 stars · license MIT · pushed 2026-10-10 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_bl6l7c44qmawlh66 GET https://markdownregistry.com/api/v1/resolve?ref=aicodedecode/awesome-muse-skills/agent-tool-builder GET https://markdownregistry.com/api/v1/blob/51b313c6bf7281e03e95aece8cd2298d85fda2957a262bda8935da22255ed91c
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
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