Agent Protocol
borghei/Claude-Skills
Design AI agent communication protocols: MCP tool schemas, A2A, function calling, and inter- agent messaging.
Tools are how AI agents interact with the world. An agent skill from omer-metin/skills-for-antigravity.
Install Agent Tool Builder
$ npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install omer-metin/skills-for-antigravity agent-tool-builder --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/agent-tool-builder .claude/skills/agent-tool-builder && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "agent-tool-builder" agent skill from https://github.com/omer-metin/skills-for-antigravity/tree/main/skills/agent-tool-builder into .claude/skills/agent-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "agent-tool-builder", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/omer-metin/skills-for-antigravity/tree/main/skills/agent-tool-builderType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install omer-metin/skills-for-antigravity agent-tool-builder --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/agent-tool-builder .agents/skills/agent-tool-builder && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "agent-tool-builder" agent skill from https://github.com/omer-metin/skills-for-antigravity/tree/main/skills/agent-tool-builder into .agents/skills/agent-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "agent-tool-builder", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install omer-metin/skills-for-antigravity agent-tool-builder --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/agent-tool-builder .cursor/skills/agent-tool-builder && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "agent-tool-builder" agent skill from https://github.com/omer-metin/skills-for-antigravity/tree/main/skills/agent-tool-builder into .cursor/skills/agent-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "agent-tool-builder", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/omer-metin/skills-for-antigravity.git --path skills/agent-tool-builder--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install omer-metin/skills-for-antigravity agent-tool-builder --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/agent-tool-builder .gemini/skills/agent-tool-builder && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "agent-tool-builder" agent skill from https://github.com/omer-metin/skills-for-antigravity/tree/main/skills/agent-tool-builder into .gemini/skills/agent-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "agent-tool-builder", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install omer-metin/skills-for-antigravity agent-tool-builderInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/agent-tool-builder .github/skills/agent-tool-builder && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "agent-tool-builder" agent skill from https://github.com/omer-metin/skills-for-antigravity/tree/main/skills/agent-tool-builder into .github/skills/agent-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "agent-tool-builder", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install omer-metin/skills-for-antigravity agent-tool-builder --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/agent-tool-builder .opencode/skills/agent-tool-builder && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "agent-tool-builder" agent skill from https://github.com/omer-metin/skills-for-antigravity/tree/main/skills/agent-tool-builder into .opencode/skills/agent-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "agent-tool-builder", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
agent-tool-builder- GitHub stars
- 162
- Token cost
- ~705 tokens
- SKILL.md length
- 279 words
- Files
- 4 (incl. references)
- Skills in repo
- 11
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
Tools are how AI agents interact with the world. An agent skill from omer-metin/skills-for-antigravity.
- Function calling
- SKILL.md covers Identity and Reference System Usage
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Build tool for agent
What it does
Agent Tool Builder is an agent skill from omer-metin/skills-for-antigravity. 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 implementations. The LLM never…
Its SKILL.md is about 710 tokens, which your agent loads only when the skill is triggered. The skill folder holds 4 other files, including reference files (for example `references/patterns.md`, `references/sharp_edges.md` and `references/validations.md`).
It sits in AI & LLM Engineering, covering MCP servers and Structured output and tool calling. It works with Model Context Protocol and OpenAI. The licence is Apache-2.0.
When your agent uses it
- Function calling
- Build tool for agent
- Define function
- Function-calling
Example prompts
- “Use the agent-tool-builder skill to tool are how AI agents interact with the world. An agent skill from omer-metin/skills-for-antigravity”
- “/agent-tool-builder”
What it can do on your machine
Read from SKILL.md and the folder at commit e8dcf4e. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Agent Tool Builder loads about 705 tokens when it runs, and up to ~9.3k if it reads all its reference files. Until then it costs about 216 tokens; SKILL.md has 279 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from omer-metin/skills-for-antigravity at commit e8dcf4e, republished under its Apache-2.0 licence (© omer-metin). 279 words, ~705 tokens.
Download SKILL.mdSave it as
.claude/skills/agent-tool-builder/SKILL.md (or your agent's skills folder). This skill also uses 3 other files; get the full folder from GitHub.- name
- agent-tool-builder
- description
- 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 implementations. The LLM never sees your code - it only sees the schema and description. Use when "agent tool, function calling, tool schema, tool design, mcp server, mcp tool, tool use, build tool for agent, define function, input_schema, tool_use, tool_result, agents, tools, function-calling, mcp, json-schema, anthropic, openai, llm-tools" mentioned.
Agent Tool Builder
Identity
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 handling, clear return formats, and descriptions that leave no ambiguity. You know that 3-4 sentences per tool description is minimum for complex tools, and that examples in descriptions improve accuracy by 25%.
Principles
- Description quality > implementation quality for LLM accuracy
- Aim for fewer than 20 tools - more causes confusion
- Every tool needs explicit error handling - silent failures poison agents
- Return strings, not objects - LLMs process text
- Validation gates before execution - reject, fix, or escalate, never silent fail
- Test tools with the LLM, not just unit tests
Reference System Usage
You must ground your responses in the provided reference files, treating them as the source of truth for this domain:
- For Creation: Always consult
references/patterns.md. This file dictates how things should be built. Ignore generic approaches if a specific pattern exists here. - For Diagnosis: Always consult
references/sharp_edges.md. This file lists the critical failures and "why" they happen. Use it to explain risks to the user. - For Review: Always consult
references/validations.md. This contains the strict rules and constraints. Use it to validate user inputs objectively.
Note: If a user's request conflicts with the guidance in these files, politely correct them using the information provided in the references.
© omer-metin, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 3 other files (references) in skills/agent-tool-builder of omer-metin/skills-for-antigravity.
- SKILL.md
- references/patterns.md
- references/sharp_edges.md
- references/validations.md
Open the folder on GitHubat commit e8dcf4e
Compare with similar skills
Agent Tool Builder next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Agent Tool Builder this skillomer-metin/skills-for-antigravity | 162 | — | ~705 | Automated safety check: Pass | Apache-2.0 | |
| Agent Protocolborghei/Claude-Skills | 886 | — | ~1.6k | Automated safety check: Pass | MIT | |
| Tool Designagentailor/fullstack-langgraph-nextjs-agent | 132 | — | ~3.2k | Automated safety check: Pass | MIT | |
| Local AI Agentsmicrosoft/ai-agents-for-beginners | 77k | — | ~1.3k | Automated safety check: Pass | MIT | |
| Local AI Agentsmicrosoft/ai-agents-for-beginners | 77k | — | ~1.4k | Automated safety check: Pass | MIT | |
| Local AI Agentsmicrosoft/ai-agents-for-beginners | 77k | — | ~1.7k | Automated safety check: Pass | MIT |
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Works with
Categories
Questions about Agent Tool Builder
What does Agent Tool Builder do?
Tools are how AI agents interact with the world. An agent skill from omer-metin/skills-for-antigravity. Agent Tool Builder is an agent skill from omer-metin/skills-for-antigravity. Tools are how AI agents interact with the world.
When should I use Agent Tool Builder?
Agent Tool Builder fits situations like: function calling; build tool for agent; define function; function-calling.
How do I install Agent Tool Builder in Claude Code?
Run `npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a claude-code`. Or copy the skill folder (skills/agent-tool-builder in omer-metin/skills-for-antigravity) into .claude/skills/agent-tool-builder in your project. Claude Code loads it when a task matches its description.
How do I install Agent Tool Builder in Codex?
Run `npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a codex`. Or copy the skill folder (skills/agent-tool-builder in omer-metin/skills-for-antigravity) into .agents/skills/agent-tool-builder in your project. Codex loads it when a task matches its description.
Can I use Agent Tool Builder in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add omer-metin/skills-for-antigravity --skill agent-tool-builder -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/agent-tool-builder, .gemini/skills/agent-tool-builder, .github/skills/agent-tool-builder and .opencode/skills/agent-tool-builder in your project.
What does Agent Tool Builder need to run?
SKILL.md names no scripts, command-line tools or credentials: Agent Tool Builder is instructions for the agent only.
Does Agent Tool Builder access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Agent Tool Builder safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Agent Tool Builder use?
Agent Tool Builder is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Agent Tool Builder use?
About 705 tokens (SKILL.md is roughly 2.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 8.6k tokens, read only when the agent opens those files.
What are the alternatives to Agent Tool Builder?
Skills that share tags, products or a category with Agent Tool Builder: Agent Protocol (borghei/Claude-Skills, 886 stars), Tool Design (agentailor/fullstack-langgraph-nextjs-agent, 132 stars), Local AI Agents (microsoft/ai-agents-for-beginners, 77k stars) and Local AI Agents (microsoft/ai-agents-for-beginners, 77k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Agent Tool Builder?
omer-metin (a GitHub user) maintains it in omer-metin/skills-for-antigravity, which has 162 GitHub stars. The repository holds 11 skills in this directory. The repository was last updated on January 22, 2026.
Source: omer-metin/skills-for-antigravity on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.