CLI-first testing — every project gets a CLI mirror

Every project should have a CLI utility that mirrors the core business logic without UI. Not a separate tool — the same modules, different entry point.

lib/pipeline/       # Business logic (pure functions, no UI)
cli/main.ts         # CLI wrapper — calls same functions as UI
app/                # UI — calls same functions from lib/pipeline/
Makefile            # make integration — runs CLI with test data

Why this matters:

• Integration testing — verifies full pipeline end-to-end without browser/simulator
• Debugging — CLI is faster to launch, simpler to debug than UI
• Pipeline-friendly — CI/CD runs make integration without headless browser
• Separation of concerns — if logic works through CLI, it doesn’t depend on UI framework

Rules:

• CLI uses same modules as UI (DRY — one implementation, two entry points)
• CLI must work without LLM / without network (deterministic fallback)
• make integration — mandatory Makefile target in every project
• /solo:scaffold generates CLI stub, /solo:build uses make integration after pipeline tasks

This is a forcing function for clean architecture: if your business logic can’t run from a CLI, it’s too coupled to the framework.

• dev-principles-summary — origin: CLI-first testing section
• one-pain-one-feature-launch — CLI enables rapid validation: ship logic, test via CLI, add UI later
• solo-methodology — make integration is mandatory in the solo dev workflow