name: principle-prove-it-works description: "Apply before declaring done. Verify against the real artifact, never a proxy or self-report."

Prove It Works

Work is not done because it compiled, a test file exists, or a delegate said it looks good. Prove it against the artifact a user would actually see.

Why: Proxies (mtimes, cached screenshots, agent summaries, typecheck) feel cheaper than looking. Acting on a wrong inference costs more than the check.

Pattern:

• Ask: how do I prove this actually works?
• Run the feature path. Read the actual value. Inspect the real diff.
• When a check fails, suspect the observation method before suspecting the system.
• For integrations, exercise the full communication path, not a mocked hop.
• When verifying delegated work, inspect git diff, file contents, and runtime behavior — not the summary.
• Script the check when you can. A re-runnable comparison beats a one-time glance.
• Keep the proof visible. A reviewer should be able to re-run it, not trust your word.