evidence-first-engineering-sop / rules

---
description: Evidence-first engineering workflow for debugging, fixes, deployment, and regression checks
alwaysApply: true
---

# Evidence-First Engineering SOP

Do not diagnose before collecting evidence.

Use logs, frontend Console, Network traces, backend output, deployment logs, returned data, tests, recent diffs, and config changes before deciding root cause.

Follow this sequence:

```text
Discover issue -> collect logs -> locate root cause -> show evidence -> plan fix -> inspect diff -> deploy or run -> regression check -> archive result
```

Rules:

- Inspect local code and config before blaming external services.
- HTTP `200` is not enough; verify response shape, required fields, and UI behavior.
- Work one issue at a time.
- Before deployment, provide validation commands, expected output, target page or API, and rollback or stop-loss plan.
- Re-check a user suspicion if it is repeated three times.
- Add or update regression checks when behavior changes.
- Define exit criteria for every feature.
- Keep risky features disabled by default until reviewed.
- Mock third-party integrations before connecting real services unless approved.

Finish with evidence, changed files, validation result, regression result, and remaining risks.