Guide · Agent skill
How to use the Contract Testing Guide agent skill
Updated · written with AI from the project's own documentation and checked against our catalogue data
The contract-testing skill is a set of instructions that teaches an AI coding agent how to help a frontend team set up consumer-driven contract testing with Pact against a backend API. It is aimed at frontend developers whose integration tests are slow or flaky because they need backend services running, and at teams deciding whether two services can be deployed independently. After reading this guide you will know what the skill does, how to install it, how to ask for it in plain language, and what infrastructure you need before it is useful.
Contract Testing Guidethedaviddias/Front-End-Checklist · MIT Download the skill Quick start
- 1Confirm the fit. Check that your project has a separate backend API and that you can access a Pact Broker and the backend CI pipeline.
- 2Download the ZIP. Download the contract-testing ZIP from the directory page.
- 3Install the skill. Unzip it into ~/.claude/skills/ for personal use or into .claude/skills/ in your project, or upload it under Settings → Capabilities → Skills in the Claude apps.
- 4Ask in plain language. Describe the API boundary or deployment question you have, naming the frontend and backend services involved.
- 5Review the agent's plan. Have the agent check for existing Pact tests before it adds anything, and confirm which interactions it proposes.
- 6Verify on the provider side. Make sure the backend CI runs provider verification against the published contracts.
What the contract-testing skill makes the agent do
Normally, checking that a frontend and a backend agree on an API means running both together in slow end-to-end tests. The skill changes the approach. The frontend records what it expects from the API as a contract, publishes that contract to a Pact Broker, and the backend verifies the contract in its own CI pipeline.
The skill gives the agent four jobs: check whether consumer-driven contract tests already exist, add Pact consumer tests for the frontend API client, explain how the Pact workflow fits together, and review existing Pact tests.
- Check: looks for contract tests that define and verify the API contract with the backend.
- Fix: adds Pact consumer tests for the frontend API client, publishes contracts to a broker, and adds provider verification to the backend CI pipeline.
- Explain: describes the workflow end-to-end and compares it with mocking and end-to-end testing.
- Code review: flags interactions that are too permissive (any-type matchers on fields the consumer uses), missing status code assertions, and interactions for endpoints the consumer no longer calls.
Check what you need before installing
The skill assumes a separate backend API. It is not useful for a project with no separate backend or a single codebase, where contract testing adds little value.
The skill requires the following. Confirm you have them before you start, because the workflow cannot run without them.
- Pact consumer and provider libraries for your language or framework.
- A Pact Broker for publishing and verifying contracts.
- CI pipeline access on the backend to run provider verification.
- Advanced difficulty: the source rates this topic as advanced and estimates about 120 minutes.
Install the skill from the ZIP or the Claude apps
Download the ZIP for the contract-testing skill from the directory page. Then choose one of two install routes.
For a personal install, unzip the file into ~/.claude/skills/. For a project install, unzip it into the project's .claude/skills/ folder. The skill folder contains SKILL.md and references/rule.md.
If you use the Claude apps, you can instead upload the skill under Settings → Capabilities → Skills.
- Personal: ~/.claude/skills/
- Project: .claude/skills/ inside your repository
- Claude apps: Settings → Capabilities → Skills
Trigger the skill with natural requests
You do not need a special command. The skill's description tells the agent when to use it, so ask in plain language about the situations it covers: setting up integration testing for a frontend-backend API boundary, judging whether two services can be deployed independently, or replacing slow end-to-end tests with contract tests.
Be specific about your stack and where the backend lives. The agent will then work from the Pact guidance in references/rule.md.
- "Do we have contract tests between the checkout frontend and the orders API?"
- "Can we deploy the frontend and the payments service independently?"
- "Replace our end-to-end login flow tests with Pact contract tests."
- "Review our Pact consumer tests for loose matchers and missing status code checks."
Safety notes: scripts and network access
The skill does not run scripts and does not use the network, according to its listing. It consists of instructions and a reference document. The agent may still edit your test files and CI configuration when you ask it to add tests, so review those changes in your normal code review process before merging.
Note that the workflow itself depends on your own Pact Broker and CI systems, which you must set up and run.
- Runs scripts: no
- Uses network: no
- Review generated test and CI changes before committing.
What people use it for
- Checking whether a frontend API client already has Pact consumer tests.
- Deciding whether two services can be deployed independently.
- Replacing a slow end-to-end test suite with consumer-driven contract tests.
- Reviewing Pact tests for overly broad matchers and missing status code assertions.
Frequently asked questions
How do I install the contract testing skill?
Download the ZIP from the directory page and unzip it into ~/.claude/skills/ for personal use, or into .claude/skills/ in a project. In the Claude apps you can instead upload it under Settings → Capabilities → Skills.
Is the contract-testing skill free?
The skill is licensed under MIT, as listed on the source repository. Pact and a Pact Broker are separate tools that you must set up yourself, and the source does not list their pricing.
What do I need to use it?
You need Pact consumer and provider libraries for your language, a Pact Broker to publish and verify contracts, and CI access on the backend to run provider verification. Without a separate backend API the skill adds little value.
Does the skill run scripts or use the network?
According to its listing, it runs no scripts and uses no network. It provides instructions and a reference file, but the agent may edit test and CI files when you ask it to.
How is contract testing different from end-to-end testing?
Contract testing lets the frontend and backend test independently while a broker ensures the published contract is verified against the live provider. End-to-end tests need both services running at the same time, which the source describes as slow and brittle.
What is a good alternative if I only need a quick answer?
The skill is not suited to one-off answers because the workflow requires a Pact Broker and CI changes. For a quick question, ask the agent to explain the approach without setting up infrastructure, or use your existing test tools.
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Our verdict
Use this skill if you have a separate backend API, want to replace slow end-to-end tests, and can run a Pact Broker and backend CI verification. Skip it for single-codebase projects or if you only want a quick answer without changing your CI setup.
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