ExpressJS MCP

--- alwaysApply: true --- # Express MCP Project Structure This project follows the FastAPI-MCP pattern for TypeScript/Express applications. ## Core Architecture The main entry point is [src/index.ts](mdc:src/index.ts), which exports the `ExpressMCP` class. ### Key Modules: - [src/routeIntrospector.ts](mdc:src/routeIntrospector.ts) - Discovers routes from Express app's `_router.stack` - [src/inMemoryDispatcher.ts](mdc:src/inMemoryDispatcher.ts) - Executes synthetic requests through middleware chain - [src/schemaResolver.ts](mdc:src/schemaResolver.ts) - Builds tool schemas from OpenAPI/annotations - [src/mcpServer.ts](mdc:src/mcpServer.ts) - HTTP gateway for MCP tools at `/mcp/tools` and `/mcp/invoke` ## Usage Patterns Mount to existing Express app: ```ts const mcp = new ExpressMCP(app, { mountPath: '/mcp' }); await mcp.init(); mcp.mount('/mcp'); ``` Standalone HTTP gateway: ```ts await mcp.startStandalone({ port: 7878 }); ``` ## Configuration - Use [package.json](mdc:package.json) with pnpm as package manager - TypeScript config in [tsconfig.json](mdc:tsconfig.json) - Biome for linting/formatting via [biome.json](mdc:biome.json) - Vitest for testing via [vitest.config.ts](mdc:vitest.config.ts) ## Testing Tests are in `tests/` directory using Vitest. Example: [tests/routeIntrospector.test.ts](mdc:tests/routeIntrospector.test.ts) ## Examples Basic usage example in [examples/basic/server.ts](mdc:examples/basic/server.ts)