Write code test-first with coverage

Enforce red-green-refactor cycle with git checkpoints and 80%+ coverage

Mission-critical code where regression risk outweighs speed, or when team coverage culture is weak.

• · user journey as failing test
• · edge cases and error scenarios

• · RED commit (test fails)
• · GREEN commit (test passes)
• · REFACTOR commit (code improves)

Git repo, test runner (Jest/Vitest/pytest), coverage tool

• · Test passes for wrong reason (incomplete assertion)
• · Refactor breaks green state

• · Mandatory RED validation before code edit
• · Checkpoint commits required
• · Coverage % enforced