How to Give Cursor Accurate API Tools with an MCP Server

Powerduck published a guide showing developers how to generate an MCP server from an OpenAPI spec, run it locally, and register it in Cursor's MCP configuration so the coding agent calls typed tools tied to real API operations instead of relying on pasted endpoint notes. The generated server regenerates when the spec is saved, keeping tools current with the contract, and reports missing operations—such as those lacking an operationId—rather than silently producing weak tools.

Short answer: Generate an MCP server from your OpenAPI spec, run it locally, and add it to Cursor's MCP configuration. The agent then calls typed tools that trace to real operations, instead of working from endpoint notes you paste into the chat. The whole setup takes minutes and survives contract changes because the server regenerates on save. Pasting a curl command or a list of endpoints into the chat works for that one session and is forgotten the next. The agent re-derives the same facts, and if the notes are stale, the agent is confidently wrong. An MCP server is a maintained interface: the tools are always present, typed, and gated by the same permission prompt as any other tool. When it works, the agent does not invent a path. It selects the tool, supplies the typed arguments, and the call log shows the operation and the returned status. If a tool is missing, the studio tells you why — usually an operation without an operationId — instead of silently producing a weak tool. The server is generated, not hand-written, so changing the spec and saving updates the tools. The discipline is simple: the contract is the source, and the agent always reads the current version. This is part of the Powerduck vs Cursor comparison https://www.powerduck.com/blog/powerduck-vs-cursor/ . See also Cursor MCP config vs a generated server https://www.powerduck.com/blog/cursor-mcp-vs-openapi-generated-mcp/ .