Agent skill

Contract Testing Patterns

Pact consumer-driven contracts, provider verification, schema evolution

MITAuto-check passedTesting & QA

Install Contract Testing Patterns

skills CLI

$ npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install vibeeval/vibecosystem contract-testing-patterns --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/vibeeval/vibecosystem.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/contract-testing-patterns .claude/skills/contract-testing-patterns && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "contract-testing-patterns" agent skill from https://github.com/vibeeval/vibecosystem/tree/main/skills/contract-testing-patterns into .claude/skills/contract-testing-patterns/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "contract-testing-patterns", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/vibeeval/vibecosystem/tree/main/skills/contract-testing-patterns

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install vibeeval/vibecosystem contract-testing-patterns --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vibeeval/vibecosystem.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/contract-testing-patterns .agents/skills/contract-testing-patterns && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "contract-testing-patterns" agent skill from https://github.com/vibeeval/vibecosystem/tree/main/skills/contract-testing-patterns into .agents/skills/contract-testing-patterns/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "contract-testing-patterns", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install vibeeval/vibecosystem contract-testing-patterns --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vibeeval/vibecosystem.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/contract-testing-patterns .cursor/skills/contract-testing-patterns && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "contract-testing-patterns" agent skill from https://github.com/vibeeval/vibecosystem/tree/main/skills/contract-testing-patterns into .cursor/skills/contract-testing-patterns/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "contract-testing-patterns", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/vibeeval/vibecosystem.git --path skills/contract-testing-patterns

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install vibeeval/vibecosystem contract-testing-patterns --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vibeeval/vibecosystem.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/contract-testing-patterns .gemini/skills/contract-testing-patterns && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "contract-testing-patterns" agent skill from https://github.com/vibeeval/vibecosystem/tree/main/skills/contract-testing-patterns into .gemini/skills/contract-testing-patterns/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "contract-testing-patterns", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install vibeeval/vibecosystem contract-testing-patterns

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/vibeeval/vibecosystem.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/contract-testing-patterns .github/skills/contract-testing-patterns && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "contract-testing-patterns" agent skill from https://github.com/vibeeval/vibecosystem/tree/main/skills/contract-testing-patterns into .github/skills/contract-testing-patterns/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "contract-testing-patterns", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install vibeeval/vibecosystem contract-testing-patterns --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vibeeval/vibecosystem.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/contract-testing-patterns .opencode/skills/contract-testing-patterns && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "contract-testing-patterns" agent skill from https://github.com/vibeeval/vibecosystem/tree/main/skills/contract-testing-patterns into .opencode/skills/contract-testing-patterns/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "contract-testing-patterns", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: contract-testing-patterns
GitHub stars: 531
Token cost: ~932 tokens
SKILL.md length: 123 words
Files: 1
Skills in repo: 144
Repo updated: Aug 8, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Pact consumer-driven contracts, provider verification, schema evolution

Tasks that involve Integration testing
SKILL.md covers Consumer-Driven Contract…, Checklist and Anti-Patterns
Needs PACT_BROKER_TOKEN

What it does

Contract Testing Patterns is an agent skill from vibeeval/vibecosystem. Pact consumer-driven contracts, provider verification, schema evolution

Its SKILL.md is about 930 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Testing & QA, covering Integration testing. The repository describes itself as: AI software team for Claude Code - 138 agents, 295 skills, 73 hooks. Self-learning, multi-agent swarm, autonomous skill evolution. The licence is MIT.

When your agent uses it

Tasks that involve Integration testing

Example prompts

“/contract-testing-patterns”

Requirements

A credential in PACT_BROKER_TOKEN

What it can do on your machine

Read from SKILL.md and the folder at commit 3b763b1. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are javascript, yaml and bash).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names these keys or tokens, usually read from environment variables:
- PACT_BROKER_TOKEN
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Contract Testing Patterns loads about 932 tokens when it runs. Until then it costs about 24 tokens; SKILL.md has 123 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~24
When it runs · the whole SKILL.md, loaded when a task matches: ~932

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from vibeeval/vibecosystem at commit 3b763b1, republished under its MIT licence (© vibeeval). 123 words, ~932 tokens.

Download SKILL.mdSave it as .claude/skills/contract-testing-patterns/SKILL.md (or your agent's skills folder).

name: contract-testing-patterns
description: Pact consumer-driven contracts, provider verification, schema evolution

Contract Testing Patterns

Consumer-Driven Contract Testing with Pact

Consumer Test (JavaScript)

javascript

const { PactV3, MatchersV3 } = require('@pact-foundation/pact');
const { like, eachLike, string, integer } = MatchersV3;

const provider = new PactV3({
  consumer: 'OrderService',
  provider: 'UserService',
  logLevel: 'warn',
});

describe('User API Contract', () => {
  it('returns user by ID', async () => {
    await provider
      .given('user with ID 1 exists')
      .uponReceiving('a request for user 1')
      .withRequest({
        method: 'GET',
        path: '/api/users/1',
        headers: { Accept: 'application/json' },
      })
      .willRespondWith({
        status: 200,
        headers: { 'Content-Type': 'application/json' },
        body: {
          id: integer(1),
          name: string('Jane Doe'),
          email: string('jane@example.com'),
          roles: eachLike('admin'),
        },
      })
      .executeTest(async (mockServer) => {
        const client = new UserClient(mockServer.url);
        const user = await client.getUser(1);
        expect(user.id).toBe(1);
        expect(user.name).toBeDefined();
      });
  });
});

Provider Verification

javascript

const { Verifier } = require('@pact-foundation/pact');

describe('User Provider Verification', () => {
  it('validates consumer contracts', async () => {
    const verifier = new Verifier({
      providerBaseUrl: 'http://localhost:3000',
      pactBrokerUrl: process.env.PACT_BROKER_URL,
      pactBrokerToken: process.env.PACT_BROKER_TOKEN,
      provider: 'UserService',
      providerVersion: process.env.GIT_SHA,
      providerVersionBranch: process.env.GIT_BRANCH,
      publishVerificationResult: true,
      stateHandlers: {
        'user with ID 1 exists': async () => {
          await db.users.create({ id: 1, name: 'Jane Doe', email: 'jane@example.com' });
        },
        'no users exist': async () => {
          await db.users.deleteAll();
        },
      },
    });
    await verifier.verifyProvider();
  });
});

Schema Evolution Rules

yaml

# Backward Compatible (SAFE):
- Adding optional fields
- Adding new endpoints
- Widening accepted value ranges
- Adding new enum values (if consumer ignores unknown)

# Breaking Changes (UNSAFE):
- Removing fields
- Renaming fields
- Changing field types
- Making optional fields required
- Narrowing accepted value ranges
- Removing endpoints

Can-I-Deploy Check

bash

# Before deploying consumer
pact-broker can-i-deploy \
  --pacticipant OrderService \
  --version $GIT_SHA \
  --to-environment production

# Before deploying provider
pact-broker can-i-deploy \
  --pacticipant UserService \
  --version $GIT_SHA \
  --to-environment production

Checklist

Every external API dependency has a consumer contract
Provider state handlers seed realistic test data
Contracts published to Pact Broker with git SHA version
can-i-deploy gate in CI pipeline before deploy
Provider verification runs on every PR
Breaking change detection automated
Contract tests run in under 30 seconds
Webhook configured to trigger provider verification on new pact

Anti-Patterns

Testing provider internal logic in consumer tests
Using exact matchers instead of type matchers (brittle)
Skipping provider states (tests pass but don't reflect reality)
Not versioning contracts with git SHA
Running contract tests against shared environments
Coupling consumer tests to provider implementation details
Ignoring can-i-deploy failures

Files

Just SKILL.md in skills/contract-testing-patterns of vibeeval/vibecosystem.

Open the folder on GitHubat commit 3b763b1

Compare with similar skills

Contract Testing Patterns next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Contract Testing Patterns compared with similar skills
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Integration E2E Testingshinpr/claude-code-workflows	690	—	~3.5k	Automated safety check: Pass	MIT	6 days ago
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Questions about Contract Testing Patterns

What does Contract Testing Patterns do?

Pact consumer-driven contracts, provider verification, schema evolution. Contract Testing Patterns is an agent skill from vibeeval/vibecosystem.

When should I use Contract Testing Patterns?

Contract Testing Patterns fits situations like: tasks that involve Integration testing.

How do I install Contract Testing Patterns in Claude Code?

Run `npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a claude-code`. Or copy the skill folder (skills/contract-testing-patterns in vibeeval/vibecosystem) into .claude/skills/contract-testing-patterns in your project. Claude Code loads it when a task matches its description.

How do I install Contract Testing Patterns in Codex?

Run `npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a codex`. Or copy the skill folder (skills/contract-testing-patterns in vibeeval/vibecosystem) into .agents/skills/contract-testing-patterns in your project. Codex loads it when a task matches its description.

Can I use Contract Testing Patterns in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add vibeeval/vibecosystem --skill contract-testing-patterns -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/contract-testing-patterns, .gemini/skills/contract-testing-patterns, .github/skills/contract-testing-patterns and .opencode/skills/contract-testing-patterns in your project.

What does Contract Testing Patterns need to run?

Going by SKILL.md and its folder, Contract Testing Patterns needs credentials named PACT_BROKER_TOKEN. Our summary lists: A credential in PACT_BROKER_TOKEN.

Does Contract Testing Patterns access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Contract Testing Patterns safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Contract Testing Patterns use?

Contract Testing Patterns is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Contract Testing Patterns use?

About 932 tokens (SKILL.md is roughly 3.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Contract Testing Patterns?

Skills that share tags, products or a category with Contract Testing Patterns: Plugin Testing (polyipseity/obsidian-terminal, 948 stars), Create Module (cartography-cncf/cartography, 4.1k stars), Td Integration Test (marcus/td, 250 stars) and Integration E2E Testing (shinpr/claude-code-workflows, 690 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Contract Testing Patterns?

vibeeval (a GitHub user) maintains it in vibeeval/vibecosystem, which has 531 GitHub stars. The repository holds 144 skills in this directory. The repository was last updated on August 8, 2026.

Source: vibeeval/vibecosystem on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Contract Testing Patterns

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Contract Testing Patterns

Consumer-Driven Contract Testing with Pact

Consumer Test (JavaScript)

Provider Verification

Schema Evolution Rules

Can-I-Deploy Check

Checklist

Anti-Patterns

Files

Compare with similar skills

Similar skills

More from vibeeval/vibecosystem

Related

Questions about Contract Testing Patterns