Contract-First Testing

Contract-First Testing is a skill for Claude Code, Codex from PramodDutta/qaskills. It costs 26 tokens per session (796 once invoked), scanned A, original, MIT.

A guide to contract-first testing, where an agreed description of an API is checked against both the software that uses it and the service that provides it.

In plain words
What is it for?
Use it to set up, review, debug, and run contract checks with Pact, Spring Cloud Contract, or Dredd.
Why use it?
It helps prevent API changes from breaking communication between services or clients.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for aider. Also seen: mentions Codex; built for aider.

Good fit Use it to set up, review, debug, and run contract checks with Pact, Spring Cloud Contract, or Dredd.

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Install with agentmods
npx agentmods add skills/pramoddutta/qaskills/contract-first-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 PramodDutta/qaskills --skill contract-first-testing
Clone the repo
git clone --depth 1 https://github.com/PramodDutta/qaskills

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-First Testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/pramoddutta/qaskills/contract-first-testing/github.svg)](https://agentmods.dev/skills/pramoddutta/qaskills/contract-first-testing)
Your own site
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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 Contract-First Testing

Your own site · 80×15
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Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 796 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
  • NVIDIA SkillSpector pass 7 Sept 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 $0.00026 $0.00796
Opus 5.5 $0.00010 $0.00318
Sonnet 5.5 $0.00005 $0.00159
Haiku 4.5 $0.00003 $0.00080

Measured 1mo ago against content hash edd51bbf1001, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

Contract-First 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 1mo 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.

seed-skills/contract-first-testing/SKILL.md · 89 lines

How it starts

The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Contract-First Testing

You are an expert QA engineer specializing in contract-first testing. When the user asks you to write, review, debug, or set up contract related tests or configurations, follow these detailed instructions.

Core Principles

  1. Quality First — Ensure all contract implementations follow industry best practices and produce reliable, maintainable results.
  2. Defense in Depth — Apply multiple layers of verification to catch issues at different stages of the development lifecycle.
  3. Actionable Results — Every test or check should produce clear, actionable output that developers can act on immediately.
  4. Automation — Prefer automated approaches that integrate seamlessly into CI/CD pipelines for continuous verification.
  5. Documentation — Ensure all contract configurations and test patterns are well-documented for team understanding.

When to Use This Skill

  • When setting up contract for a new or existing project
  • When reviewing or improving existing contract implementations
  • When debugging failures related to contract
  • When integrating contract into CI/CD pipelines
  • When training team members on contract best practices

Implementation Guide

Setup & Configuration

When setting up contract, follow these steps:

  1. Assess the project — Understand the tech stack (typescript, javascript, java) and existing test infrastructure
  2. Choose the right tools — Select appropriate contract tools based on project requirements
  3. Configure the environment — Set up necessary configuration files and dependencies
  4. Write initial tests — Start with critical paths and expand coverage gradually
  5. Integrate with CI/CD — Ensure tests run automatically on every code change

Best Practices

  • Keep tests focused — Each test should verify one specific behavior or requirement
  • Use descriptive names — Test names should clearly describe what is being verified
  • Maintain test independence — Tests should not depend on execution order or shared state
  • Handle async operations — Properly await async operations and use appropriate timeouts
  • Clean up resources — Ensure test resources are properly cleaned up after execution

Read the full file on GitHub · 89 lines

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. 1mo ago First seen · 89 lines · 26 tokens per session scan A edd51bbf1001

Subscribe to this mod's changes

Contract-First Testing is a skill published in the GitHub repository PramodDutta/qaskills (237 stars, last pushed 8d ago), licensed MIT. It adds 26 tokens to every session and 796 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-03.