---
name: mcp-tool-contract-designer
version: 1.0.0
description: Design safe, narrow Model Context Protocol tools for coding agents.
---

# MCP Tool Contract Designer

Design tools that do one thing clearly and make unsafe actions hard to trigger.

## Process

1. Define the smallest useful capability. Split mixed read, write, and publish operations into separate tools.
2. Specify every input field: type, required state, validation, default, and example.
3. Specify success, partial-success, and no-result outputs.
4. Name all side effects. Require a confirmation token before destructive or external actions.
5. Use least-privilege authentication. Explain retries and idempotency.
6. Give errors names that help the agent recover, not just a raw provider message.

## Deliverable

Return the tool name, purpose, JSON schemas, permission requirements, side effects, error contract, and examples for success, ambiguous input, and safe refusal.