Contract Test
Validate API contracts with consumer-driven testing and OpenAPI validation
- Type
- Slash Command
- Repository
- jeremylongshore/tons-of-skills-marketplace
- GitHub stars
- 2.8k
- License
- MIT
- Repo last updated
- Sep 27, 2026
What Contract Test is
Contract Test is a slash command published in the jeremylongshore/tons-of-skills-marketplace repository on GitHub, which has about 2.8k stars. The repository describes itself as: “Model-agnostic agent-skills platform with a harness-free canonical layer, verified adapters, and the ccpi package manager. Explore at tonsofskills.com.”
A slash command is a reusable prompt saved as a markdown file and run by typing its name after a slash. In Claude Code, custom commands have been merged into skills: a file in .claude/commands/ and a skill folder in .claude/skills/ both create the same kind of command, and existing command files keep working.
Contract Test gives you a repeatable way to run the same instructions without retyping them, optionally with arguments.
How to install Contract Test
Claude Code
- Download contract-test.md from the repository.
- Save it to ~/.claude/commands/ (all projects) or .claude/commands/ (one project). As a skill, you can instead save it as ~/.claude/skills/<name>/SKILL.md.
- Run it by typing / followed by its name.
Claude Cowork
- Turn the command into a skill: create a folder with the file saved as SKILL.md and zip it.
- In Customize → Skills, click +, then upload the ZIP.
- Run it from any task with / and the skill name.
New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.
Inside the source file
An excerpt from plugins/testing/contract-test-validator/commands/contract-test.md, shared under the repository's MIT license. Read the full file on GitHub.
Implement and validate API contracts using consumer-driven contract testing (Pact), OpenAPI specification validation, and microservices contract verification.
What You Do
- Generate Contract Tests
- Create Pact consumer tests from API usage
- Generate provider verification tests
- Build OpenAPI contract validators
- Validate Contracts
- Verify API responses match contracts
- Check backward compatibility
- Validate request/response schemas
- Contract Evolution
- Detect breaking changes
- Suggest versioning strategies
- Generate migration guides
- Integration Setup
- Configure Pact Broker
- Set up CI/CD contract testing
- Implement contract test gates
Usage Pattern
When invoked, you should:
- Analyze API endpoints and their consumers
- Generate appropriate contract tests (Pact or OpenAPI)
- Validate existing contracts against implementations
- Identify contract violations or breaking changes
- Provide recommendations for contract evolution
- Set up contract testing infrastructure
Output Format
## Contract Testing Report
### APIs Analyzed: [N]
#### API: [Name]
**Type:** [REST / GraphQL / gRPC]
**Contract Format:** [Pact / OpenAPI / Proto]
**Consumers:** [N]
- [Consumer 1]: [status]
- [Consumer 2]: [status]
**Contract Status:**
Valid contracts: [N]
Warnings: [N]
Breaking changes: [N]
### Breaking Changes Detected
…Supported Patterns
- Consumer-driven contracts (Pact)
- OpenAPI 3.x specification validation
- GraphQL schema contracts
- gRPC/Protobuf contracts
- JSON Schema validation
- Spring Cloud Contract
Before you install
- Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
- Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
- Try it in a test project or a copy of your files before pointing it at real work.
- Pin the version you tested, and review changes before updating.
- Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.
FAQ
What is Contract Test?
Contract Test is a slash command for Claude Code and Claude Cowork from the jeremylongshore/tons-of-skills-marketplace repository on GitHub. Validate API contracts with consumer-driven testing and OpenAPI validation
How do I install Contract Test in Claude Code?
Download contract-test.md from the repository. Save it to ~/.claude/commands/ (all projects) or .claude/commands/ (one project). As a skill, you can instead save it as ~/.claude/skills/<name>/SKILL.md. Run it by typing / followed by its name.
Can I use Contract Test in Claude Cowork?
Turn the command into a skill: create a folder with the file saved as SKILL.md and zip it. In Customize → Skills, click +, then upload the ZIP. Run it from any task with / and the skill name.
Is Contract Test safe to install?
It is a third-party community resource, not reviewed by Anthropic or this site. Read the source file first, check which tools and connectors it uses, and install only from sources you trust.
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