Overview
agent-tool-builder is an open-source workflow skill for Claude Code and compatible agents, published by sickn33. Its author describes it as: “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…”. The project has 47k stars on GitHub and is available under the MIT license. Add it to your setup with `/plugin marketplace add sickn33/agentic-awesome-skills`.
What agent-tool-builder does
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.
What’s inside
The SKILL.md for agent-tool-builder is organised into these sections:
- Detailed Guide
- Python Example
- When to Use
- Limitations
Installation
Add agent-tool-builder to your agent with:
/plugin marketplace add sickn33/agentic-awesome-skillsReview a skill’s source before installing it — skills can instruct your agent to run commands. This command comes from the skill’s public repository, which is the source of truth for setup steps. New to skills? Read how to install Claude Code skills.
Supported agents
- Claude Code — ships a claude code plugin marketplace
- Codex — declared in the repository topics
- Cursor — declared in the repository topics
- Gemini CLI — declared in the repository topics
- Antigravity — declared in the repository topics
License
agent-tool-builder is published under the MIT license.
Strengths
- Clear MIT license — safe to read and adapt within its terms
- Ships in sickn33/agentic-awesome-skills, an established project with 46,693 GitHub stars
- Works with Claude Code, Codex, Cursor, Gemini CLI, Antigravity
- Actively maintained — repository updated in the last 30 days
- Its repository gained 2,482 GitHub stars over the last 52 days
Author
Topics
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Frequently asked questions
- What does agent-tool-builder do?
- 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.
- How do I install agent-tool-builder?
- Run /plugin marketplace add sickn33/agentic-awesome-skills in your agent, then reload your skills. Review the source at https://github.com/sickn33/agentic-awesome-skills before installing.
- Is agent-tool-builder free to use?
- Yes. agent-tool-builder is free and open source under the MIT license, so you can read, run, and adapt it within that license's terms.
- Which agents does agent-tool-builder work with?
- agent-tool-builder lists Claude Code, Codex, Cursor, Gemini CLI, and Antigravity — named in its SKILL.md, its plugin marketplace or its repository topics. Skills use the portable SKILL.md format, so other agents that read that format may load it too.
- Where does agent-tool-builder come from?
- agent-tool-builder ships inside sickn33/agentic-awesome-skills, a repository that contains 70 catalogued skills in total. The repository's 46,693 GitHub stars apply to that whole collection, not to this skill on its own.