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/agent-tool-builder

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

From plugin
claude-code-templates
31k200 skills200 agents200 commands32 MCP
Install
$ npx -y skills add davila7/claude-code-templates --skill agent-tool-builder --agent claude-code

How it fires

How this skill gets triggered: by you, by Claude, or both.

  • Fires itselfAuto-invocation. Claude auto-loads it when your prompt matches the work.Auto-invocation is when the right skill fires by itself at the right moment, driven by a FLOW.md router and a hook, instead of you invoking it by name. It is the difference between a skill being installed and a skill actually getting used.Read the full definition →
  • You can call itInvoke it directly when you want it.
  • Slash command/agent-tool-builder

Context preview

The summary Claude sees to decide when to auto-load this skill.

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

SKILL.md

agent-tool-builder.SKILL.md
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 implementa"
source: vibeship-spawner-skills (Apache 2.0)

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 more
Ships withclaude-code-templates

Ready-to-use configurations for Anthropic's Claude Code. A comprehensive collection of AI agents, custom commands, settings, hooks, external integrations (MCPs), and project templates to enhance your development workflow.

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