The Courier MCP Server Is Open Source. Here's How It Actually Works.

Courier's MCP server, now open source on GitHub, is a TypeScript project that extends the @modelcontextprotocol/sdk and registers 16 tool classes for various functions including sending messages, managing documents, and automating tasks. Two notable features include the SdkContextTools class, which detects the Courier SDK version in use and provides appropriate usage rules to the LLM, and the DocsTools class, which fetches installation guides from GitHub and generates live JWTs. The server operates as a hosted HTTP service but can also be run locally for development. It allows the registration of specific tools based on user needs to prevent degradation of client performance due to tool overload. Additionally, the server is designed to be safe for AI agents by restricting delete operations on core resources and limiting administrative updates, ensuring it can be used for building and testing without risking unintended modifications to the user account. The project is open for contributions, with its repository available on GitHub for those interested in reporting bugs, suggesting new tools, or integrating the SDK context detection into the server entrypoint.