debugging

Common issues, Developer Mode, version compatibility, and session and stream diagnosis

npx skills add https://github.com/facebook/meta-wearables-dat-android --skill 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

No eligible device or session won't start?
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+-- Did you call Wearables.initialize(context)? -> Must happen before SDK usage
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+-- Did registration complete? -> Observe Wearables.registrationState
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+-- Is Developer Mode enabled? -> Enable it in the Meta AI app for dev builds
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+-- Does Wearables.devices contain a linked device? -> Check Bluetooth and range
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+-- 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 for the current compatibility matrix.

Logging

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.