This is an MCP (Model Context Protocol) server that auto-generates AI-agent-friendly tools from the Notion REST API OpenAPI specification. It runs as a CLI tool (stdio transport) or an HTTP server (Streamable HTTP transport), exposing 24 tools covering users, search, blocks, pages, comments, data sources, and databases — including dedicated markdown read/write endpoints. The architecture follows a clean three-layer design: an OpenAPI-to-MCP converter (`parser.ts`) that transforms each operation into a tool with JSON Schema input/output; an MCP proxy (`proxy.ts`) that handles tool listing/calling and deserializes double-encoded JSON parameters (a known MCP client issue); and an HTTP client (`http-client.ts`) that executes the actual API calls using axios and openapi-client-axios. Notable engineering highlights include per-operation `Notion-Version` header sourcing from the spec (so each endpoint can pin its required API version), a per-request token passthrough mechanism for multi-tenant deployments, and comprehensive test coverage with snapshot tests locking the tool surface. The repo is well-structured TypeScript with clear separation of concerns, though the README signals that this local MCP server may be sunset in favor of a newer remote MCP offering.