pact-contract-testing

pact-contract-testing is a skill for Claude Code from aks-builds/quality-skills. It costs 132 tokens per session (2,320 once invoked), scanned A, original, MIT.

A guide for Pact, a tool that checks whether software services agree on how they communicate. Consumer-driven contract testing lets the service that uses an API define expected behavior, which the service providing that API must verify.

In plain words
What is it for?
Use it to design or run Pact tests, publish and verify contracts, configure matching rules, and add deployment checks for APIs shared between services.
Why use it?
It catches communication changes that could break another service before those services are deployed independently. It also explains how a Pact Broker or Pactflow coordinates these checks between teams.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the quality-skills plugin — 57 skills shipped together

Good fit Use it to design or run Pact tests, publish and verify contracts, configure matching rules, and add deployment checks for APIs shared between services.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aks-builds/quality-skills/pact-contract-testing
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add aks-builds/quality-skills --skill pact-contract-testing
Clone the repo
git clone --depth 1 https://github.com/aks-builds/quality-skills

Made for: Claude Code.

Or install quality-skills, the plugin that ships this one along with the rest of its 57 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for pact-contract-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/aks-builds/quality-skills/pact-contract-testing/github.svg)](https://agentmods.dev/skills/aks-builds/quality-skills/pact-contract-testing)
Your own site
<a href="https://agentmods.dev/skills/aks-builds/quality-skills/pact-contract-testing"><img src="https://agentmods.dev/badge/skills/aks-builds/quality-skills/pact-contract-testing/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for pact-contract-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/aks-builds/quality-skills/pact-contract-testing"><img src="https://agentmods.dev/badge/skills/aks-builds/quality-skills/pact-contract-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 132 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,320 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00132 $0.02320
Opus 5 $0.00066 $0.01160
Sonnet 5 $0.00026 $0.00464
Haiku 4.5 $0.00013 $0.00232

Measured 9d ago against content hash 63c73f5ca5a1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

pact-contract-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/pact-contract-testing/SKILL.md · 215 lines

How it starts

The opening of the file, as written. The whole thing — 215 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pact Contract Testing

You are an expert in consumer-driven contract testing with Pact. Your goal is to help engineers design, implement, and operate contract tests across consumer and provider sides, plus the Pact Broker / Pactflow workflow that makes contract testing scalable. Don't fabricate Pact method names, broker API endpoints, or matcher syntax — point to docs.pact.io when uncertain.

Initial Assessment

Check .agents/qa-context.md (fallback: .claude/qa-context.md) before answering. Pay attention to:

  • Architecture — Pact is most useful in microservice / multi-service architectures where consumers and providers are owned by different teams and deploy independently. For a monolith, contract testing is usually overkill.
  • Languages — Pact has official implementations in JavaScript/Node, Java/JVM, Python, Ruby, Go, .NET, Rust, PHP, Swift. The consumer and provider can be in different languages.
  • Broker — Pact Broker (self-hosted) or Pactflow (managed). Without a broker, contract testing is much less valuable because you lose the deployment-coordination workflow.
  • CI maturity — Pact's value compounds when wired into CI with can-i-deploy gates. Manual workflows are fragile.

If the file does not exist, ask: architecture (number of services, ownership boundaries), consumer/provider languages, broker (Pact Broker / Pactflow / none yet), and CI provider.


What contract testing is — and isn't

Is: an agreement between a consumer (e.g., a mobile app) and a provider (e.g., a payments API) about the shape of HTTP requests/responses they exchange. The consumer writes a Pact test that says "when I send this request, I expect this response shape." The provider then runs a verification that says "if I receive that request, I produce that response shape." The agreement (the pact file) is the contract.

Isn't:

  • Not load testing.
  • Not functional testing — pacts test shape, not business logic.
  • Not a replacement for E2E — there are integration concerns pacts can't catch.
  • Not auto-generated documentation, although it doubles as one.
  • Not useful for system boundaries where you don't control both sides (e.g., a third-party API you can't ask to verify).

Read the full file on GitHub · 215 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 215 lines · 132 tokens per session scan A 63c73f5ca5a1

Subscribe to this mod's changes

pact-contract-testing is a skill published in the GitHub repository aks-builds/quality-skills (2 stars, last pushed 6d ago), licensed MIT. It adds 132 tokens to every session and 2,320 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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