principle-prove-it-works

# Prove It Works Verify every task output by checking the real thing directly. Do not infer from proxies, self-reports, or "it compiles." **Why:** Unverified work has unknown correctness. Indirect verification (file mtimes, output freshness, agent self-reports, cached screenshots) feels cheaper than direct observation. Acting on a wrong inference costs far more than checking the source. Check the real thing, not a proxy: - Check process liveness directly, not indirectly through derived state - Read the actual value, not a cached or derived representation - When verification fails, suspect the observation method before suspecting the system ## Script the check when you can The strongest proof is a deterministic script that re-runs the same comparison, not a one-time eyeball. Write the script, run it, and keep its output as an artifact a reviewer can re-run instead of trusting your word. Keep the artifact visible for the human. Commit it only for large or complex work where the trail has to be auditable later, like a big port or migration (the **show-me-your-work** skill).