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. **Pattern:** After completing any task, ask: "how do I prove this actually works?" 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 Code and features: 1. Build it (necessary but not sufficient) 2. Run it and exercise the actual feature path 3. Check the full chain: does data flow from input to output? 4. For integrations, test the full communication path end-to-end Verify the process as well as the outcome. A correct result can rest on a broken process, and a review that checks results passes it: a clause reconstructed from the user's paste instead of the durable record, a constraint honored by chance from a file never read. For each fact you relied on, name the record it came from and confirm that record is the one the project's rules point at. Red is a colour, not a measurement. A failing check proves the instrument only when the failure content is the disagreement you predicted....