M.010.18 — Android Samsung DeX Holographic Handoff (Execution Spec)

Date: 2026-04-04
Owner: Copilot execution lane
Status: Ready for implementation

Goal

Enable seamless handoff of a running mobile holographic session into Samsung DeX desktop mode, preserving:

• scene graph state
• camera/view parameters
• active interaction context
• session identity and permissions

The result is a user flow where a phone becomes a desktop holographic workspace without a restart.

Why this opens doors

• Gives immediate enterprise demo value (phone-to-desk continuity)
• Differentiates from static AR demos by showing persistent spatial workflow
• Reuses existing .holo graph model while exposing a practical, user-visible win

Product behavior

1. User starts a .holo scene on Android phone.
2. User enters Samsung DeX mode (dock/cable/wireless DeX).
3. Runtime detects mode transition and emits session_handoff_requested.
4. State snapshot is serialized to a handoff payload.
5. Desktop DeX runtime initializes using payload.
6. User resumes in the same scene context (state + camera + tool mode).

Scope

In scope (v1)

• DeX mode detection and transition eventing
• Scene snapshot serialization/deserialization
• Session continuity contract (HandoffPayload)
• Recovery behavior on partial handoff failure
• Telemetry for handoff latency and failure classes

Out of scope (v1)

• Cross-device handoff between different physical phones
• Multi-user collaborative handoff merge
• Full GPU context transfer (state-level transfer only)

Technical architecture

1) Runtime mode detector

Add Android runtime probe:

• source: display + desktop-mode state
• output: mobile | dex
• event: runtime_mode_changed

2) Handoff payload contract

interface HandoffPayload {
  version: 'm010.18.v1';
  sessionId: string;
  sceneId: string;
  timestamp: string;
  camera: {
    position: [number, number, number];
    rotation: [number, number, number];
    fov?: number;
  };
  interaction: {
    activeTool?: string;
    selectedIds: string[];
    cursor?: [number, number, number];
  };
  sceneStateDelta: Record<string, unknown>;
  capabilityFlags: {
    dexKeyboardMouse: boolean;
    externalDisplay: boolean;
  };
}

3) Handoff orchestrator

Two-phase transfer:

1. prepare_handoff(payload) — freeze transient mutations, emit checkpoint
2. commit_handoff(payload) — initialize DeX view and resume event loop

Fallback path:

• if commit fails, revert to mobile loop and display non-destructive warning

4) Renderer adaptation (DeX)

• switch input mapping to mouse/keyboard-first
• preserve gesture compatibility when touch is still present
• increase UI density and panel layout for desktop viewport

Proposed code touch points

• packages/runtime/:
  • add mode detector module
  • add handoff orchestrator and payload codec
• packages/core/:
  • add HandoffPayload shared type and schema validation
• packages/studio/ (if using studio-hosted preview path):
  • add handoff telemetry panel or debug logs

Failure taxonomy

• DEX_NOT_AVAILABLE
• PAYLOAD_SCHEMA_INVALID
• SCENE_DELTA_DESERIALIZE_FAILED
• CAPABILITY_MISMATCH
• COMMIT_TIMEOUT

Each failure must include user-safe fallback and telemetry emission.

Acceptance criteria (v1)

1. Entering DeX triggers handoff flow automatically.
2. Scene object states match pre-handoff snapshot within deterministic tolerance.
3. Active tool + selection survives handoff.
4. End-to-end handoff completes under 1500ms on target Samsung test device.
5. On failure, user remains in functional mobile session with no scene corruption.

Test plan

Unit

• payload schema validation
• camera/tool/selection serialization round-trip
• failure-class mapping

Integration

• simulated mobile -> dex mode switch
• orchestrator two-phase commit behavior
• fallback rollback on forced commit failure

Device validation

• Samsung DeX wired mode
• Samsung DeX wireless mode
• external keyboard/mouse input continuity

Shipping slices

Slice A (2-3 days)

• payload contract + schema + unit tests
• mode detector + event wiring

Slice B (3-4 days)

• orchestrator prepare/commit + rollback path
• integration tests

Slice C (2 days)

• input/layout adaptation for DeX
• telemetry + final device validation

Metrics

• handoff_attempt_total
• handoff_success_total
• handoff_failure_total{code}
• handoff_latency_ms
• handoff_rollback_total

Definition of done

• All acceptance criteria pass
• integration tests are green
• device validation checklist complete on at least one Samsung DeX-capable device
• docs updated with user-facing handoff behavior and known limits