contract-testing

contract-testing is a skill for Claude Code, Codex from petrkindlmann/qa-skills. It costs 151 tokens per session (3,604 once invoked), scanned A, original, MIT.

A guide to consumer-driven contract testing with Pact-JS version 16. Contract tests check that a service provider delivers the API behavior its consumers depend on.

In plain words
What is it for?
Use it to write Pact consumer tests, verify providers through a broker, add deployment checks, configure webhooks and pending contracts, or compare consumer-first and schema-first API testing.
Why use it?
It catches breaking changes between independently deployed services before they reach deployment or production.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to write Pact consumer tests, verify providers through a broker, add deployment checks, configure webhooks and pending contracts, or compare consumer-first and schema-first API testing.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/petrkindlmann/qa-skills/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 petrkindlmann/qa-skills --skill contract-testing
Clone the repo
git clone --depth 1 https://github.com/petrkindlmann/qa-skills

Made for: Claude Code, Codex.

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 contract-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/petrkindlmann/qa-skills/contract-testing.svg)](https://agentmods.dev/skills/petrkindlmann/qa-skills/contract-testing)
Your own site
<a href="https://agentmods.dev/skills/petrkindlmann/qa-skills/contract-testing"><img src="https://agentmods.dev/badge/skills/petrkindlmann/qa-skills/contract-testing.svg" alt="Measured on agentmods" height="20"></a>
Per session 151 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,604 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. Third-party audits
  • Socket pass 11 May 2026
  • Snyk warn 11 May 2026
How audits are shown
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 $0.00151 $0.03604
Opus 5 $0.00076 $0.01802
Sonnet 5 $0.00030 $0.00721
Haiku 4.5 $0.00015 $0.00360

Measured 7d ago against content hash fc69dd9b0e72, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

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 7d 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/contract-testing/SKILL.md · 205 lines

How it starts

The opening of the file, as written. The whole thing — 205 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Discovery Questions

Check .agents/qa-project-context.md first — if it exists, use it and skip anything already answered there. Then:

  1. Architecture: Microservices, monolith with separate consumers (mobile/SPA), or BFF pattern? Contract testing matters most when teams deploy independently.
  2. Who owns the contract? Consumer-driven (consumers define what they need) or provider-driven (provider publishes a spec)? Most teams benefit from consumer-driven.
  3. API versioning strategy: URL-based (/v1/, /v2/), header-based, or none? Contracts must account for version negotiation.
  4. How many consumer-provider pairs? Start with the highest-traffic or most-fragile integration. Do not try to contract-test everything at once.
  5. Existing API specs: Is there an OpenAPI/Swagger spec? If yes, consider schema-first contracts (or Schemathesis) as a starting point.
  6. HTTP or async? Request/response APIs use the HTTP examples here; queue/topic integrations (Kafka, SNS/SQS) use Pact message contracts (see Pact-JS Setup).

Core Principles

1. Consumers define what they need, providers verify they can deliver. The consumer writes a test declaring "I will call GET /users/123 and expect { id, name, email }." The provider runs this test against its real implementation. If the provider cannot satisfy the contract, the build breaks before deployment.

Read the full file on GitHub · 205 lines

Files

What ships with it

3 files 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. 7d ago First seen · 205 lines · 151 tokens per session scan A fc69dd9b0e72

Subscribe to this mod's changes

contract-testing is a skill published in the GitHub repository petrkindlmann/qa-skills (110 stars, last pushed 2mo ago), licensed MIT. It adds 151 tokens to every session and 3,604 once invoked, about $0.0008 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 2026-08-30.

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