# OpenAPI to AI Agent Tool Definitions Converter

Convert an OpenAPI specification into tool definitions for OpenAI-style function calling, Anthropic tool use or MCP.

- URL: https://toolstackhub.co.uk/tools/openapi-to-agent-tools/
- Category: Developer Tools
- Price: free, no sign-up
- Privacy: runs in the browser; input is not uploaded
- Last updated: 2026-10-08

## About
Upload or paste an OpenAPI 3 specification in JSON or YAML. The converter turns each operation into a tool definition with a safe name, a description, and a JSON Schema for its parameters and request body, in the format you choose: OpenAI function calling, Anthropic tool use or MCP. It resolves local $ref references and warns about missing descriptions, long names and large schemas. It produces definitions only: your application still has to make the HTTP calls and handle authentication. Your spec stays in your browser.

## How to use
1. Choose your file using the file picker above. It stays on your device.
2. Adjust any options that appear.
3. Download the finished file.

## FAQ
**Does it call my API?** No. It only converts the specification into tool definitions. Your code makes the real HTTP requests and decides which operations the model may use.

**Which OpenAPI versions work?** OpenAPI 3.x in JSON or YAML works best. Swagger 2 specs often convert, but body and parameter handling is simpler for 3.x.

**Is the OpenAPI to AI Agent Tool Definitions Converter free?** Yes, with no sign-up or limits.