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CodingIntermediate

API Contract Test Harness Pack

Generate contract tests that catch breaking API changes between producer and consumer services — extract the contract, map consumer expectations, produce failing tests, and get safe versioning guidance.

A 4-step agentic workflow pack for coding built to run with ChatGPT, Claude, Cursor, and Gemini. Open the Markdown files, fill the variables, and paste into your model. Most buyers get a reviewable result in about 10 minutes.

  • Extract a precise API contract from any spec, OpenAPI doc, or service code in minutes
  • Map exactly what each consumer relies on so tests guard the right fields and status codes
  • Generate ready-to-run contract tests that fail the moment a breaking change reaches the producer
  • Receive safe versioning and deprecation guidance so breaking changes ship with a migration path, not a production incident
CChatGPTClaudeClaudeCursorCursorGeminiGemini
promptscart.com / prompt-packs / api-contract-test-harness-prompt-pack
Run in
ChatGPT · Claude +2
Your AI model
Step 1
Contract Extractor
Paste your OpenAPI spec, proto file, or service code and receive a structured contract table listing every endpoint, method, required fields, and expected response shapes.
Step 2
Consumer Expectation Mapper
Paste the extracted contract and a description of each consumer service and get a per-consumer expectation table showing the exact fields and codes each consumer relies on.
Step 3
Contract Test Generator
Paste the consumer expectation map and target language and receive ready-to-copy contract test stubs with assertions scoped to each consumer's expectations.
Step 4 · optional
Versioning Guidance
Describe the change you want to make and paste the consumer expectation map and receive a recommended versioning strategy — additive, versioned, or deprecation-with-sunset.
Output
Your deliverable
Copy-paste ready
One-time
$6
~5 hrs / week
time back

Prompt Customization Serviceoptional help adapting variables and output to your brand voice. Choose your tier at checkout (not tied to this prompt's price).

Instant download after payment
Refund as per the Refund Policy.
Email Support · 24h SLA
Lifetime updates

Models supported
C ChatGPTClaude ClaudeCursor CursorGemini Gemini
Best valueSave $786
Get this pack + 101 more in the Lifetime Bundle

This pack is $6 on its own. Buying every pack separately costs $935. The Lifetime Bundle is $149 one-time — you save $786 (84% off) and unlock every future pack free.

Get the Lifetime Bundle — $149
Already purchased?
Download API Contract Test Harness Pack

Paste the license key from your receipt. It must match this prompt pack.

What ships with your purchase

Prompt files

Plain Markdown files with `{{variables}}` you fill in, ready to paste into ChatGPT, Claude, or Gemini. No setup, no tooling required.

Usage guide

Variable reference, model compatibility, examples, and customization tips so you can adapt the pack to your brand voice.

Lifetime updates

When we improve the pack, you get the new version automatically. Email support included with every purchase.

Models tested: ChatGPT, Claude, Cursor, Gemini.

The workflow inside this pack

4 composable prompts you run in order — each one picks up where the last left off.

  1. Step 1

    Contract Extractor

    Paste your OpenAPI spec, proto file, or service code and receive a structured contract table listing every endpoint, method, required fields, and expected response shapes.

  2. Step 2

    Consumer Expectation Mapper

    Paste the extracted contract and a description of each consumer service and get a per-consumer expectation table showing the exact fields and codes each consumer relies on.

  3. Step 3

    Contract Test Generator

    Paste the consumer expectation map and target language and receive ready-to-copy contract test stubs with assertions scoped to each consumer's expectations.

  4. Step 4 · optional

    Versioning Guidance

    Describe the change you want to make and paste the consumer expectation map and receive a recommended versioning strategy — additive, versioned, or deprecation-with-sunset.

Perpetual (lifetime) use license

Your one-time purchase includes an ongoing right to use this prompt pack with the AI tools and models you control for your own and your clients' work — not for resale or public redistribution of the files as a product.

We keep the copyright

The prompt files, guides, examples, and bundled assets stay our copyrighted works (or our licensors'). Payment grants the limited license in our Terms only — it does not transfer ownership.

Need help adapting this prompt to your team? Add Prompt Customization Service at checkout.

FAQ

How long does it take to use API Contract Test Harness Pack?
Most buyers finish in a few minutes: open the prompt file, fill the variables, and paste into your model. The first run is the slowest because you decide variable values; reuse is instant.
What if I get stuck?
Email support@promptscart.com. Free basic support is included with every purchase, and you'll get a reply from our team within 24 hours. If you need help adapting variables or output, we can schedule a call.
Do I need a paid plan with ChatGPT?
The prompt works on free tiers of ChatGPT, Claude, and Gemini. Heavy use can hit free-tier limits; paid plans get longer context and faster responses, but the prompt itself is the value.
Can I customize the prompt?
Yes, completely. You own the prompt files: edit the role framing, add variables, swap output sections, fork it to match your brand voice. Support can help you plan customizations over email.
What if it doesn't work for me?
Refund as per our Refund Policy (https://promptscart.com/refund-policy). Or add Prompt Customization Service at checkout for help adapting variables and output to your workflow.