Development

Agent Tool Builder

Version1.0.0

LicenseMIT

Token count~417

UpdatedMay 27, 2026

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 implementa

Install

Quick install

via npx skills · works with 57+ agents

npx skills add https://github.com/davila7/claude-code-templates/tree/main/cli-tool/components/skills/ai-research/agent-tool-builder

Or pick agent:

npx skills add davila7/claude-code-templates --skill agent-tool-builder --agent claude-code

npx skills add davila7/claude-code-templates --skill agent-tool-builder --agent cursor

npx skills add davila7/claude-code-templates --skill agent-tool-builder --agent codex

npx skills add davila7/claude-code-templates --skill agent-tool-builder --agent opencode

npx skills add davila7/claude-code-templates --skill agent-tool-builder --agent github-copilot

npx skills add davila7/claude-code-templates --skill agent-tool-builder --agent windsurf

More install options

Shorthand — useful for multi-skill repos:

npx skills add davila7/claude-code-templates --skill agent-tool-builder

Manual — clone the repo and drop the folder into your agent's skills directory:

git clone https://github.com/davila7/claude-code-templates.git

cp -r claude-code-templates/cli-tool/components/skills/ai-research/agent-tool-builder ~/.claude/skills/

How to use: Once installed, ask your agent to "use the agent-tool-builder skill" or describe what you want (e.g. "Tools are how AI agents interact with the world. A well-designed tool is the dif"). Requires Node.js 18+.

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

SKILL.md source

---
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 necessar...
---

# 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`

Development