mcp-builder

Build MCP servers using FastMCP (Python) or MCP SDK (Node/TypeScript) to enable LLMs to interact with external services. Design tools with clear naming, input validation using Pydantic or Zod schemas, robust error handling, and appropriate response formatting to support agent workflows.

Design tools by prioritizing agent needs: use descriptive names, include annotated metadata (title, inputSchema, annotations), implement strict input validation with Pydantic or Zod, provide actionable error messages, handle pagination where needed, and optimize response formats for limited context windows.

Yes. MCP servers work across Python (using FastMCP and Pydantic) and Node/TypeScript (using MCP SDK and Zod). Both stacks support the same core patterns: tool design, validation, error handling, and transport protocols like stdio, SSE, and HTTP.

Use Pydantic for Python validation schemas or Zod for TypeScript to enforce input constraints. Implement structured error handling with clear, actionable messages that help agents understand failures and retry appropriately.

MCP supports stdio, SSE (Server-Sent Events), and HTTP transports. Choose based on your deployment model: stdio for local integration, SSE or HTTP for remote or scalable architectures.

Create realistic, complex evaluation questions that test server functionality end-to-end. Include read-only test cases and edge scenarios to verify tool behavior, error handling, and response quality under actual agent usage patterns.