Api Contract Tester

    5

    Turn OpenAPI specs into exhaustive, framework-ready test suites covering happy paths, edge cases, and security gaps.

    $5

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    Claude CodeClaude CodeCursorCursorCodex CLICodex CLIMuseMuseDotsDots+21 more

    api-contract-tester

    Example session with this skill installed

    I need to test the user registration endpoint at /v1/users. Can you generate some Jest tests to validate the request body, specifically focusing on email validation errors?

    • Read your context and instructions
    • Compiled the api-contract-tester

    "test_user_registration_invalid_email":

      it("returns 422 when email is missing '@'", async () => {
    const res = await request(app).post("/v1/users").send({ email: "bad-email" });
    expect(res.status).toBe(422);
    expect(res.body.errors).toContainEqual(expect.objectContaining({ field: "email" }));
  });

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    About this skill

    Exhaustive API Contract & Regression Testing

    Transform your OpenAPI specs or Postman collections into professional-grade test suites. Unlike basic tools that only check for "200 OK" responses, this skill acts as a senior quality engineer to probe the boundaries of your API. It identifies off-by-one errors, authentication vulnerabilities, and schema mismatches before they reach production.

    What it does

    • Parse & Analyze: Extracts endpoints, schemas, and constraints from OpenAPI/Swagger, Postman, or raw code.
    • Constraint Testing: Generates tests for min/max values, regex patterns, and enum boundaries.
    • Security First: Automatically builds suites for missing tokens, malformed JWTs, and unauthorized cross-user access.
    • Robust Validation: Checks for breaking changes between versions, including field removals and type shifts.
    • Framework Flexibility: Generates code for Jest, Pytest, Vitest, Playwright, or curl scripts.

    Why use this skill

    Writing comprehensive API tests is tedious and manual. This skill automates the creation of "the tests developers forget"—such as testing rate-limit headers, pagination boundaries, and SQL injection strings. It ensures consistent error response formats and prevents internal stack traces from leaking to users. The result is a production-ready test suite with a detailed coverage report across 10 distinct categories.

    Supported Outputs

    • JavaScript/TypeScript: Jest, Vitest, Supertest, Playwright.
    • Python: Pytest with requests or httpx.
    • DevOps: Shell scripts using curl with assertions.
    • Reporting: Markdown-based coverage reports across happy paths, auth, and edge cases.

    • Cannot execute/run tests; only generates the code.
    • Cannot probe live private APIs without user-provided auth tokens or tunnel access.
    • Inferences from raw code depend on language clarity.

    How to use

    1. 1

      Connect your agent to the Agensi MCP

      Copy the prompt and paste it into Claude, ChatGPT, Cursor or any agent that supports MCP. It sets up the connection for you. Manual setup

    2. 2

      Sign in to Agensi

      Your agent shows a sign-in link. Sign in and click Allow.

    3. 3

      Ask for what you need

      Your agent loads this skill and uses it on your task. It always asks before any payment.

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    2 uses

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    Security scan passed 7 months ago

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    Listed7 months ago

    What's inside

    Frequently Asked Questions

    This skill automatically transforms OpenAPI/Swagger specs or Postman collections into deep test suites that cover edge cases, security vulnerabilities, and schema constraints that manual testing often misses.

    The skill is framework-agnostic and can generate fully functional test code for Jest, Pytest, Vitest, Playwright, and even raw curl scripts for CI/CD pipelines.

    Absolutely. It is specifically designed to perform regression testing by comparing different versions of an API to detect breaking changes, type shifts, or missing fields.

    Beyond simple '200 OK' checks, it automatically generates tests for unauthorized access, malformed tokens, rate-limiting headers, and boundary-value analysis for input fields.

    You get the full capability to parse documentation into test suites, generation of code for your chosen framework, and a comprehensive markdown coverage report.

    To get started, simply provide your OpenAPI specification (JSON/YAML) or a Postman collection link, and specify your preferred testing framework (e.g., Pytest or Jest).

    New in Testing & Debugging