openapi-to-mcp

# Build an MCP server from an OpenAPI spec Turn an existing REST API — described by an OpenAPI 3.x or Swagger 2.0 document — into an MCP server. Each operation in the spec becomes one MCP tool the LLM can call. The server runs locally for testing and ships to Manufact / mcp-use cloud with one command. This skill is the end-to-end recipe: scope → ingest spec → map operations → scaffold → generate tools → wire auth → test → deploy. ## Core philosophy: the spec is the contract The OpenAPI document is the source of truth. Tool names, descriptions, parameter shapes, and auth requirements all come from the spec — they should not be invented. This matters because: - **The LLM trusts descriptions.** If the spec says `summary: "Get current weather for a city"`, that's exactly what the LLM will read when deciding whether to call the tool. Hand-rolled summaries drift; spec-derived summaries stay in sync if the API changes. - **Zod schemas mirror OpenAPI schemas.** Every parameter — path, query, body — becomes a field in one zod object. Required/optional, enums, min/max, and descriptions all carry over. The LLM uses the schema to figure out what to ask the user for. - **Auth lives outside the spec.** OpenAPI declares the auth scheme but never the secret. Secrets come from env vars; the spec tells you which env vars to require. When in doubt, prefer mechanical fidelity to the spec over creativity. The LLM is doing the creative part — talking to the user — and only needs a faithful, ...