lean-loop

[](LICENSE) [](https://opencode.ai)

Run this command to begin your first Lean Loop cycle:

opencode "Implement a greet(name) function that returns 'Hello, {name}!': Start with PLAN phase"

A disciplined heartbeat cycle for AI-assisted and human-driven TDD development.

    PLAN ──────► APPLY ──────► UNIFY
     ▲                              │
     └──────────────────────────────┘

AI coding assistants are powerful but chaotic. They write code fast, skip tests, lose context, and rarely reconcile what was planned vs. what was built. Lean Loop fixes that with three simple rules:

• Plan before you code. Define acceptance criteria before touching any file.
• Test every behavior. Strict Red-Green-Refactor, one test at a time.
• Reconcile every cycle. Compare plan vs. actual, log decisions, update state.

The result: predictable, auditable, test-covered development — whether you're working solo, with a team, or alongside an AI.

Let's walk through your first complete Lean Loop cycle together. We'll build a simple greet(name) function that returns a greeting message. This tutorial takes about 5-10 minutes and requires no prior setup beyond having Node.js installed.

First, let's create a new project folder and set up Lean Loop:

mkdir my-first-loop && cd my-first-loop
npm init -y  # Creates a basic package.json
npx skills add oxyplay/lean-loop -g  # Installs the Lean Loop skill

This automatically creates a .system/ folder with all the tracking files we need.

Open .system/PLAN.md in your editor and replace the content with:

# Objective
Add a `greet(name)` function th