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Build MCP with Agent

Create custom MCP servers through AI-guided development using the built-in MCP Builder tool.

What is MCP Builder

MCP Builder enables agents to design and develop FastMCP-based servers through natural conversation. Instead of writing code manually, you collaborate with an agent to:

  • Define tool requirements through Q&A
  • Get FastMCP framework guidance
  • Design tool implementations
  • Auto-generate server configurations
  • Install and register servers automatically

Why Build with Agent

Quick Start No FastMCP expertise required. The agent provides templates, examples, and best practices.

Guided Development The agent asks clarifying questions to understand your needs, then designs an appropriate solution.

Automated Setup From approved design to working MCP server in one step—no manual configuration.

Iterative Refinement Review drafts, provide feedback, and iterate until the tool meets your requirements.

How It Works

  1. Tell the agent what you need "I need a tool to fetch weather data from an API"

  2. Answer clarifying questions The agent asks about API sources, authentication, data format, etc.

  3. Review the proposed design Agent presents code structure, tool definitions, and configuration

  4. Provide feedback and iterate Request changes: "Add error handling" or "Support multiple cities"

  5. Approve and register Agent automatically creates the server, installs dependencies, and registers it

Complete Documentation

For detailed information about MCP Builder capabilities, workflows, and best practices:

→ MCP Builder Tool Documentation

This comprehensive guide covers:

  • Development workflows (creating and optimizing tools)
  • FastMCP best practices and patterns
  • Document structure and XML tags
  • Automatic registration process
  • Integration with file tools
  • Common use cases and examples

Quick Example

User: "Create a currency converter tool using an exchange rate API"

Agent: "I'll help you build that. A few questions: - Which exchange rate API? (e.g., exchangerate-api.io, fixer.io) - Do you have an API key? - Which currencies to support?"

User: "Use exchangerate-api.io, I have a key, support major currencies"

Agent: "I'll design a FastMCP server with a convert_currency tool. Let me create the specification..."

[Agent creates mcp/currency_converter.md with complete code and config]

Agent: "Here's the design. The tool takes base currency, target currency, and amount. It handles API errors and validates inputs. Would you like any changes?"

User: "Looks good, register it"

Agent: "Registering currency_converter..." [Automatic folder creation, dependency installation, MCP registration]

Agent: "Done! The currency_converter server is now available in your MCP servers list."

Next Steps