Outside In Tdd Starter

Outside-In TDD Starter

An outside-in test-driven development workflow that runs inside Claude Code. It starts from E2E tests and drills down through architecture layers, writing tests before implementation at every level.

This repo serves two purposes:

1. Sandbox — A working todo app where you can try out the workflow immediately
2. Starter template — Clone it, strip out the todo app, and build your own project with Outside-In TDD from day one

Quick Start

Prerequisites

- Docker Desktop
- Node.js (v20+)
- Claude Code CLI installed

Setup

Services will be running at:

Try It Out

Open Claude Code in the project directory and ask it to implement a feature:

The outside-in-tdd skill triggers automatically for feature requests. Claude will plan, write a failing E2E test, then cycle through RED-GREEN-REFACTOR for each layer until the feature is complete.

How It Works

When you ask Claude Code to implement a feature, the orchestrator runs four phases. The workflow completes one architecture layer at a time (e.g., frontend first, then backend). Within each layer, it writes all failing tests across every unit (components, hooks, routes, etc.) in a single RED phase, then implements all changes in a single GREEN phase — minimising the number of agent handoffs to reduce time cost.

How Agents Find Their Skills

Each TDD phase is handled by a specialized agent. Agents discover project-specific patterns through the registry:

- Test-writer, refactorer, test-backfiller load the testing skill for the layer
- Implementer loads the implementation skill for the layer (if one exists)

This keeps context focused — agents only load what they need for their specific task.

File Structure

Generic Framework (reusable across projects)

These files contain workflow logic only. They…