Diagnose Power Apps mobile install/startup failures, npm run dev errors, missing package entry points, or QR/device-opening problems even before an app is loaded. Inspect locally first; restore locked dependencies or restart Metro only with explicit approval, never upgrade packages or patch host/MSAL source. For a running native app, monitor sanitized project-local Metro logs and diagnose runtime errors or silent failures such as empty lists and blank screens. Supports startup-only diagnosis, symptoms, port/platform filters, bounded monitoring, and non-mutating --no-fix mode. Verify the original symptom, not merely installation or quiet logs.