⚡ Instant Tools

OpenAPI to MCP Server

Convert OpenAPI or Swagger specs into a Model Context Protocol server for Cursor, Claude Desktop, and AI agents. Free, no signup.

Privacy: Your OpenAPI file never leaves this browser. Parsing and codegen are 100% client-side.

1. Paste or upload OpenAPI

How to Use

  1. 1Paste OpenAPI JSON/YAML or upload a .json / .yaml file (or load the sample).
  2. 2Check the agent-readiness score and fix critical issues in your spec when possible.
  3. 3Pick TypeScript or Python, confirm the base URL, and select endpoints to expose.
  4. 4Generate the project, download the ZIP, install deps, and wire Cursor or Claude Desktop.

Example: Petstore → Cursor MCP

Input

openapi: 3.0.3 — GET/POST /pets, GET /pets/{petId}, ApiKeyAuth (X-API-Key)

Paste JSON or YAML, or click Load sample on the tool page.

Output tools

list_pets · create_pet · get_pet

Downloadable TypeScript or Python MCP package with cursor-mcp.json for Cursor Settings → MCP.

Agent readiness

Score ~96 on the sample (operationIds + descriptions present)

Thin summaries, missing operationIds, and large DELETE surfaces lower the score.

Best practices for agent-ready APIs

  • •Add unique operationId values so tool names stay stable across regenerations.
  • •Write clear summaries: agents pick tools from descriptions, not just path strings.
  • •Exclude admin, internal, and destructive DELETE routes unless the agent truly needs them.
  • •Prefer flat request bodies and enums over deep oneOf/$ref graphs for better tool calling.
  • •Keep secrets in env vars (.env.example is generated for you).

Frequently Asked Questions

What is an MCP server?

MCP (Model Context Protocol) lets AI clients like Cursor and Claude Desktop call external tools. An MCP server wraps your REST API so an agent can list pets, create invoices, or hit any endpoint as a typed tool instead of guessing raw HTTP.

Does my OpenAPI spec leave my browser?

No. Parsing and code generation run entirely in your browser. Instant Tools never uploads your OpenAPI or Swagger file to a server.

Which OpenAPI versions are supported?

OpenAPI 3.0 and 3.1 (JSON or YAML) work best. Swagger 2.0 is supported on a best-effort basis. Local #/ $refs are resolved; remote $refs are flagged as warnings.

How do I use the generated server in Cursor?

Download the ZIP, run npm install (or pip install for Python), set env vars from .env.example, then add the included cursor-mcp.json snippet to Cursor Settings → MCP (or .cursor/mcp.json) with an absolute path to the project folder.

TypeScript or Python: which should I pick?

TypeScript (official @modelcontextprotocol/sdk) is the default for Cursor and Claude Desktop. Choose Python if your team already uses FastMCP. Both expose the same tools from your OpenAPI operations.

Is this OpenAPI to MCP converter free?

Yes. No signup, no usage limits, and no watermark on generated code. You own the output.

Will every endpoint become a good MCP tool?

Not always. Specs missing operationIds, thin descriptions, or dozens of admin/DELETE routes confuse agents. Use the readiness score, exclude noisy endpoints, and improve summaries in your OpenAPI before shipping.

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