TDD Guard

[!IMPORTANT]

TDD Guard grew into Probity: the same

TDD enforcement, now for Claude Code, Codex, and GitHub Copilot CLI, with

more reliable validation and no test reporters to set up. New projects should

start there. TDD Guard remains maintained for the projects that rely on it.

Automated Test-Driven Development enforcement for Claude Code.

TDD Guard blocking TDD violations

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.