OpenRouter MCP Server

# CLAUDE.md This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository. ## Development Commands ```bash # Development with hot reload npm run dev # Production build npm run build # Run production server npm start # Run tests (Jest framework) npm test # Lint TypeScript code npm run lint ``` ## Environment Setup Copy `.env.example` to `.env` and configure: - `OPENROUTER_API_KEY` - Required for OpenRouter API access - `OPENROUTER_BASE_URL` - Defaults to https://openrouter.ai/api/v1 - `OPENROUTER_SITE_URL` - Your site URL for API attribution - `OPENROUTER_APP_NAME` - Application name for API headers ## Architecture Overview This is a **Model Context Protocol (MCP) server** written in TypeScript that provides Claude access to 400+ AI models through OpenRouter's API. ### Core Architecture **Single-file implementation**: `src/server.ts` contains the complete `OpenRouterMCPServer` class **MCP Tools Provided**: - `list_models` - Get available OpenRouter models - `chat_with_model` - Send messages to specific models - `compare_models` - Compare responses from multiple models - `get_model_info` - Get detailed model information **MCP Resources Exposed**: - `model_pricing` - Pricing information for models - `model_capabilities` - Model capabilities and features - `usage_stats` - Usage statistics (placeholder) ### Key Dependencies - `@modelcontextprotocol/sdk` - MCP protocol implementation - `axios` - HTTP client for OpenRouter API - `zod` - Runtime type validation and schemas - `dotenv` - Environment variable management ### Testing - **Framework**: Jest (configured but no tests implemented yet) - **Setup**: Dependencies must be installed first (`npm install`) - **ES Modules**: Requires TypeScript + ESM Jest configuration ### Claude Desktop Integration Use `examples/claude-config.json` as a template for Claude Desktop MCP server configuration. The server communicates via stdio transport following MCP protocol standards. ## Code Patterns - **Schema-first design**: All API requests/responses validated with Zod schemas - **Error handling**: Comprehensive try-catch blocks around external API calls - **Async/await**: Consistent async pattern with Promise.all for parallel requests - **Environment-based config**: Secure API key management through environment variables ## Development Best Practices - Remember to always use yarn to install run dependencies. - For build and run command as well use yarn