⚡ Instant Tools

OpenAPI to Tool Schemas

Convert OpenAPI or Swagger into Zod, JSON Schema, OpenAI function tools, and Anthropic input schemas. Free, no signup.

Privacy: Your OpenAPI file never leaves this browser. Conversion is 100% client-side.

1. Paste or upload OpenAPI

How to Use

  1. 1Paste OpenAPI JSON/YAML or upload a spec (or load the sample).
  2. 2Select the operations you want as agent tools.
  3. 3Pick Zod, JSON Schema, OpenAI, and/or Anthropic outputs.
  4. 4Generate, copy into your app, or download the ZIP. Validate with MCP Tool Checker if needed.

Example outputs

Zod

export const ListPetsInputSchema = z.object({ limit: z.number().int().optional() })

TypeScript validators with inferred types.

OpenAI tools

{ "type": "function", "function": { "name": "list_pets", "parameters": { ... } } }

Drop into Chat Completions tools arrays.

Anthropic tools

{ "name": "list_pets", "input_schema": { "type": "object", ... } }

Messages API tool definitions with input_schema.

Schema tips for reliable tool calling

  • •Add operationId and clear summaries so tool names and descriptions stay stable.
  • •Prefer enums and required fields over optional free-form strings.
  • •Exclude admin/DELETE routes unless the agent should mutate production data.
  • •Use Zod in TypeScript apps; use OpenAI/Anthropic JSON for hosted LLM APIs.
  • •Need a Cursor MCP process? Use OpenAPI to MCP after you like these schemas.

Frequently Asked Questions

What does OpenAPI to Tool Schemas produce?

It turns OpenAPI/Swagger operations into agent-ready input schemas: Zod TypeScript, JSON Schema, OpenAI function tools, and Anthropic tools with input_schema — without generating a full MCP server process.

How is this different from OpenAPI to MCP?

OpenAPI to MCP builds a runnable MCP server package for Cursor/Claude Desktop. This tool emits portable schema files for function calling, validation, and custom agent runtimes. Use both: schemas for apps, MCP for IDE agents.

Which OpenAPI versions are supported?

OpenAPI 3.0/3.1 (JSON or YAML) work best. Swagger 2.0 is best-effort. Local #/ $refs are resolved in-browser; remote $refs are not fetched.

Does my OpenAPI leave the browser?

No. Parsing and codegen run entirely client-side. Instant Tools never uploads your specification for this tool.

Can I use the OpenAI tools JSON with the Responses API?

The openai-tools.json file follows the Chat Completions tools shape ({ type: "function", function: { name, description, parameters } }). Adapt field names if your SDK expects the newer flat function tool format.

Is this converter free?

Yes. No signup, no usage limits, and you own the generated schemas.

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