TDD Guard
Pre-tool hook that blocks code edits unless a failing test exists first — enforces strict test-first discipline by refusing file writes without a red test in scope.
TDD Guard
Automated Test-Driven Development enforcement for Claude Code.
TDD Guard ensures Claude Code follows Test-Driven Development principles. When your agent tries to skip tests or over-implement, TDD Guard blocks the action and explains what needs to happen instead.
Features
- Test-First Enforcement - Blocks implementation without failing tests
- Minimal Implementation - Prevents code beyond current test requirements
- Lint Integration - Enforces refactoring using your linting rules
- Customizable Rules - Adjust validation rules to match your TDD style
- Flexible Validation - Choose faster or more capable models for your needs
- Session Control - Toggle on and off mid-session
Getting Started
Requirements
- Node.js 22+
- A supported test framework (Vitest, Jest, Storybook, pytest, PHPUnit, Go, Rust, RSpec, Minitest)
Installation
Open Claude Code in your project and run:
/plugin marketplace add nizos/tdd-guard/plugin install tdd-guard@tdd-guard/tdd-guard:setup
This adds the marketplace, installs the plugin, and configures the test reporter for your project. You may need to restart your terminal session or IDE extension for the setup skill to appear. For manual installation and configuration, see the installation guide.
Configuration
- Custom instructions - Customize TDD validation rules
- Lint integration - Automated refactoring support
- Strengthening enforcement - Prevent agents from bypassing validation
- Ignore patterns - Control which files are validated
- Validation Model - Choose faster or more capable model
- All settings - Complete settings documentation
Security
TDD Guard hooks run with your user permissions. We maintain automated security scanning, dependency audits, and welcome source code review. See Claude Code's security considerations for more on hook safety.
Development
Contributing
Contributions are welcome! See the contributing guidelines to get started.
Contributors:
- Python/pytest support: @Durafen
- PHP/PHPUnit support: @wazum
- Rust/cargo support: @104hp6u
- Go support: @sQVe, @wizzomafizzo
- Storybook support: @akornmeier
- Ruby/RSpec & Minitest support: @Hiro-Chiba
Roadmap
- Expand language and test framework support
- Validate file modifications made through MCPs and shell commands
- Encourage meaningful refactoring opportunities when tests are green
- Add support for multiple concurrent sessions per project
Related Projects
Probity
Enforces TDD and other policies across Claude Code, Codex, and Copilot. Works with any language and test runner. Uses session activity for validation, giving it a fuller picture when distinguishing refactors from new behavior.
For new projects, Probity is the better starting point. Stay on TDD Guard if you use its lint integration. Probity doesn't have an equivalent yet.
Support
- Discussions - Ask questions and share ideas
- Issues - Report bugs and request features
License
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