ck:mcp-builder

To build an MCP server, use this framework to design, implement, and evaluate servers using Python FastMCP or Node/TypeScript SDKs. It covers tool design, API integration, resources, and structured outputs for reliable end-to-end server development.

The best way to validate inputs and handle errors in MCP server tool design is to enforce input validation with Pydantic or Zod. The framework also enforces tool annotations, structured outputs, pagination, character limit handling, and secure error handling.

Yes, you can use both Python FastMCP and Node/TypeScript MCP SDKs for server development. The framework provides guidelines and patterns for tool design, API integration, and resource management across both Python and TypeScript ecosystems.

You evaluate MCP servers by using the provided evaluation scaffolding and best-practice workflows. Initialize a minimal server skeleton, register a single tool, and use the evaluation harness to verify the end-to-end tool invocation flow produces verifiable assessments.

Yes, MCP server development requires structured outputs like JSON and Markdown. The framework enforces YAML frontmatter metadata, tool annotations, pagination, character limit handling, and structured outputs to enable reliable tool use by LLMs.