/live-debugging-mcp

name: live-debugging-mcp
description: Use this whenever debugging an iOS DAT app with local DAT Inspector MCP tools, live device events, Meta AI app/device boundary issues, permissions, registration, sessions, streaming, callbacks, or user reports that the app cannot communicate with glasses.

Live DAT Debugging with MCP (iOS)

Use this skill when a developer is debugging an iOS DAT app and has a local DAT Inspector MCP server or DAT debug server available to the agent. This is the live-runtime counterpart to `dat-docs-mcp`: use docs search for API lookup, and use this skill for observed app/device behavior.

Ground rules

• Stay read-only unless the user explicitly asks for an app code change.
• Do not mutate Meta AI app, device, account, permission, registration, or app

state.

• Treat companion-app/device results as boundary diagnosis from app-visible DAT

events, not as direct access to companion app internals.

• Use live DAT evidence before guessing: registration, permissions, device

selection, link state, session state, stream state, typed errors, and SDK logs.

• If the MCP tools are not configured, ask the developer to enable their local

DAT debug setup and fall back to logs plus `search_dat_docs`.

Normal agent loop

1. Discover and connect to the running app debug server:

• `discover_debug_servers`
• `connect_to_debug_server`

2. Establish the baseline with all three calls before diagnosing deeper:

• `get_connection_status`
• `get_sdk_state`
• `get_dat_readiness`

Do not skip `get_connection_status`; it separates MCP/debug-server connectivity from SDK, registration, permission, session, and stream state. 3. If the issue looks like Meta AI app or device boundary behavior, inspect:

• `get_companion_boundary_diagnosis`
• `get_device_path`
• `get_permissions`
• `get_device_properties`

4. Ask the developer to reproduce the failing iOS flow while connected. 5. Wait for narrow evidence instead of polling everything:

• `wait_for_events` with `category` or `source`
• `get_errors`
• `get_event_digest`

6. For handoff, collect a redacted bundle:

• `export_diagnostic_bundle`

Evidence map

• Configuration: app logs around `Wearables.configure()`
• URL callbacks: `Wearables.shared.handleUrl(_:)` return handling
• Registration: `Wearables.shared.startRegistration()` and

`wearables.registrationState`

• Device availability: device selectors, `wearables.devices`,

`device.compatibility`, and `device.properties`

• Device link: `device.linkState`
• Permissions: DAT permission APIs, `device.permission`, `check_permissions`,

and `get_permissions`

• Session: `DeviceSession` creation/start, `deviceSession.state`,

`session.state`, and session errors

• Stream: stream start, `stream.state`, frame counters, and stream errors
• DAM/DWA-visible transport: DAM/DWA error values

Diagnosis patterns

• Registration blocked: verify Info.plist DAT configuration, app URL scheme,

Developer Mode setup, and callback handling.

• No eligible device: inspect discovered devices, selector behavior, device

compatibility, and `device.linkState` before changing stream code.

• Permission failure: use `get_permissions` and `get_companion_boundary_diagnosis`;

do not assume iOS system permission is the same as DAT permission through the Meta AI app/device boundary.

• Session fails before stream creation: inspect session errors and selected

device compatibility before changing camera code.

• Stream fails after session start: inspect stream state, camera permission, and

recent errors before changing frame processing.

Output expectations

When summarizing, name the evidence plane, the blocking state, and the next developer action. Example:

DAT readiness is blocked at registration: the app-visible registration state is
not registered. Check the Info.plist DAT URL scheme and MetaAppID, complete the
Meta AI callback through handleUrl(_:), then retry while the MCP connection waits
for registration and device-link events.