Mcp Builder

What it does

The Mcp Builder skill enables AI agents to quickly build and deploy Model Context Protocol (MCP) servers in Python using the FastMCP framework. It scaffolds a working server from a description, allowing you to define tools (callable functions), resources (readable data), and prompts (reusable templates). The tool supports local testing modes and deployment options including FastMCP Cloud, Docker, and Cloudflare Workers.

When to use it

• You need to create an MCP server for Claude AI agents to interact with custom tools or data.
• You want a rapid way to prototype and deploy simple agent workflows using the Model Context Protocol.
• You are building a system where Claude needs to call specific functions (tools) or access particular data resources.

Key capabilities

• Server Scaffolding: Generates a basic Python MCP server structure based on a description of desired functionality.
• Tool, Resource & Prompt Definition: Supports defining callable tools, readable resources, and reusable prompt templates within the server.
• Local Testing Modes: Provides options for direct execution, development mode with auto-reload, and HTTP transport for testing.
• Deployment Options: Enables deployment to FastMCP Cloud, Docker containers, or Cloudflare Workers.
• Pre-deploy Checklist: Includes a checklist to identify common issues before deploying the server.

Example prompts

• "Build an MCP server for querying our customer database."
• "Create an MCP server with a tool that searches customers by name and a resource providing customer details."
• "Scaffold a FastMCP server with a function called 'search_customers' that takes a query string as input."

Tips & gotchas

• The generated server instance must be at the module level for deployment to FastMCP Cloud.
• Install fastmcp using pip install fastmcp before creating the server file.
• For Claude Code terminal use, companion CLI scripts can be added alongside the MCP server.