REST API Contract Generator

    1

    Generate standardized REST API contracts and OpenAPI-ready documentation from code or descriptions.

    Free

    1 installSecurity scanned

    Works with the AI tools you already use

    Claude CodeClaude CodeCursorCursorCodex CLICodex CLIGitHub CopilotGitHub CopilotGemini CLIGemini CLI+20 more

    REST API Contract Generator

    Example session with this skill installed

    Generate an API contract for a POST /auth/register endpoint that takes email and password. Password must be 8 chars. Return a 201 on success or 400 if the email exists.

    • Read your context and instructions
    • Compiled the rest api contract

    I have generated the API contract for the registration endpoint, including validation rules and standard error responses.

    API Contract: User Registration

    Endpoint: POST /auth/register
    Description: Registers a new user account using an email address and password.
    Auth Required: No

    📥 Request:

    • Headers: Content-Type: application/json
    • Parameters: None
    • Body Example:
    {
  "email": "user@example.com",
  "password": "securePassword123"
}
    • Validation:
      • email: Required, must be a valid RFC 5322 format.
      • password: Required, minimum 8 characters.

    📤 Responses:

    • 201 Created: User successfully registered.
    {
  "id": "uuid-v4-string",
  "email": "user@example.com",
  "created_at": "2023-10-27T10:00:00Z"
}
    • 400 Bad Request: Email already in use or validation failed.
    {
  "error": "Email already exists",
  "code": "DUPLICATE_USER"
}
    • 500 Internal Server Error: Unexpected server-side failure.
    {
  "error": "Internal server error",
  "code": "SERVER_ERROR"
}

    Next steps

    • Copy the body schema into your frontend validation logic.
    • Add the 400 error handling to your registration form UI.
    • Export this to your openapi.yaml file for Swagger UI synchronization.

    Connects securely to your tools. The creator never sees your data.

    About this skill

    The problem

    Writing API documentation is tedious and error-prone. Frontend and backend teams often drift out of sync because updating OpenAPI specs manually is the first task developers skip during rapid iteration.

    What it does

    • Extracts HTTP methods, paths, and authentication requirements from raw code or descriptions.
    • Defines strict request schemas including headers, query parameters, and validation rules like min-length or regex.
    • Generates comprehensive response schemas for success states and standardized error codes (400, 401, 404, 500).
    • Produces OpenAPI-ready structures that can be dropped directly into YAML or JSON specifications.

    Frameworks & tools

    Compatible with any REST-based stack including Node.js, Python FastAPI, Go, and Ruby on Rails. Outputs standard OpenAPI/Swagger formats.

    Why this beats prompting it yourself

    Generic LLMs often forget to include critical error states or omit validation logic found in your code. This skill enforces a strict contract structure that covers edge cases, headers, and specific data types required for production-grade documentation.

    Use cases

    • Documenting a new route immediately after writing the controller logic.
    • Generating a mock contract for frontend developers before the backend is built.
    • Updating outdated Swagger files during a major API refactor.
    • Standardizing error response formats across a microservices architecture.

    How to install

    Works the same in every agent - Claude, Cursor, Codex, Copilot and 20+ more.

    ~30 seconds
    1. 1

      Download the ZIP

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    2. 2

      Unzip into your skills folder

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    3. 3

      Ask your agent to use it

      Restart the agent if it was already running. It picks the skill up automatically - no config needed.

    Skills folder by agent

    Click the path to copy it. Create the folder if it does not exist yet.

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    Security scanned

    Verified clean 17 days ago

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    Listed17 days ago

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