debugging

# Debugging (Android) Diagnose common setup, session, and stream issues in DAT SDK integrations. If local DAT Inspector MCP tools are available, use the `live-debugging-mcp` skill before changing app code. Prefer `get_dat_readiness`, `get_companion_boundary_diagnosis`, and `get_device_path` to separate app bugs from Meta AI app/device boundary issues using read-only DAT evidence. ## Quick diagnosis ```text No eligible device or session won't start? | +-- Did you call Wearables.initialize(context)? -> Must happen before SDK usage | +-- Did registration complete? -> Observe Wearables.registrationState | +-- Is Developer Mode enabled? -> Enable it in the Meta AI app for dev builds | +-- Does Wearables.devices contain a linked device? -> Check Bluetooth and range | +-- Did createSession() or addCamera() return a DatResult failure? -> Surface the typed error ``` ## Developer Mode Developer Mode must be enabled for local development builds that use `mwdat_application_id = 0` and `mwdat_client_token = 0`. ### Symptoms when Developer Mode is disabled - Registration flow completes but the device never becomes eligible - Permission requests do not succeed for development builds - `Wearables.createSession(...)` fails with no eligible device ### Watch for - Developer Mode may reset after app or firmware updates - Developer Mode is configured per linked device - Production builds use a real `APPLICATION_ID`, `CLIENT_TOKEN`, and release-channel gating instead ## Session and stream issues ### Session never reaches `STARTED` - Verify `Wearables.registrationState` - Check that `Wearables.devices` contains a compatible linked device - Ensure the glasses are powered on, unfolded, and in range ### Stream never reaches `STREAMING` - Confirm `session.start()` succeeded before calling `session.addCamera(...)` - Check camera permission status through `Wearables.checkPermissionStatus(...)` - Make sure `camera.stream.start()` returned success ### Photo capture fails - `capturePhoto()` only succeeds while the stream is actively streaming - Surface the returned `CaptureError` instead of discarding the `DatResult` ## Version compatibility Ensure compatible versions of the SDK, Meta AI app, and glasses firmware. See [version dependencies](https://wearables.developer.meta.com/docs/version-dependencies) for the current compatibility matrix. ## Logging ```kotlin private const val TAG = "DATWearables" camera.stream.start() .onFailure { error, _ -> Log.e(TAG, "Failed to start stream: ${error.description}") } ``` Prefer logging typed `DatResult` failures and observed state transitions over generic exceptions. ## Live MCP evidence When the developer has a local DAT debug server connected to the agent: - Start with `get_sdk_state` and `get_dat_readiness` - Use `get_companion_boundary_diagnosis` for permission, app identity, device capability, device-selection, deeplink-return, and DAM/DWA-visible blockers - Use `get_device_path` to trace app -> DAT registration -> Meta AI app permissions -> device selection/link -> session -> stream - Ask the developer to reproduce the issue, then use `wait_for_events` with the narrowest category or source that matches the flow - Use `export_diagnostic_bundle` for redacted support handoff Do not treat this as companion app introspection. It is diagnosis from app-visible DAT debug events. ## Checklist - [ ] `Wearables.initialize(context)` ran before SDK usage - [ ] Developer Mode enabled for development builds - [ ] `APPLICATION_ID` and `CLIENT_TOKEN` match the build mode - [ ] Registration completed before session creation - [ ] Bluetooth permission granted - [ ] Camera permission granted through Meta AI - [ ] Session and stream `DatResult` failures are surfaced in logs or UI ## Links - [Known issues](https://wearables.developer.meta.com/docs/knownissues) - [Version dependencies](https://wearables.developer.meta.com/docs/version-dependencies) - [Troubleshooting discussions](https://github.com/facebook/meta-wearables-dat-android/discussions)