Iterative Development Skill (Stop Hook TDD Loops)

Concept: Claude Code's Stop hook fires right before Claude finishes a response. Exit code 2 feeds stderr back to the model and continues the conversation. This creates a real TDD loop without any plugins.

How It Actually Works

Claude Code has a Stop hook that runs when Claude is about to conclude its response. If the hook script exits with code 2, its stderr is shown to the model and the conversation continues automatically.

┌─────────────────────────────────────────────────────────────┐
│  1. User asks Claude to implement a feature                 │
├─────────────────────────────────────────────────────────────┤
│  2. Claude writes tests + implementation                    │
├─────────────────────────────────────────────────────────────┤
│  3. Claude finishes its response                            │
├─────────────────────────────────────────────────────────────┤