2026-04-28 - Phi E5 Direct ObjC Event Bind Outcome

Intent: Determine whether explicitly attaching CoreML completion/wait shared events is enough to make raw Phi stage B consume stage A’s output.

Setup: Added --objc-sync-bind-direct, which calls _bindNewCompletionEventsDirectlyWithCompletionSyncPoint: on stage A and _bindNewWaitEventsDirectlyWithWaitSyncPoints: on stage B after manual input/output port binding.

Result: The direct bind hooks work structurally. Stage A’s completionSharedEventBoundToESOP and stage B’s waitSharedEventsBoundToESOP contain the same _MTLSharedEvent. Raw prepare, encode, and execute still return success. Stage A remains correct, but stage B remains all zeros.

Surprise / hurdle: Attaching the event object is not enough; the missing behavior is likely future-value update/signaling, raw encode consumption of the event state, or a separate output backing synchronization step.

Lesson: The dependency problem is narrower now: event objects can be attached, but CoreML’s normal lifecycle does more than attach them.

Next: Trace prepareAsyncSubmissionForInputFeatures:options:error: or the normal async path to see when future values are updated and when E5RT encode consumes event dependencies.

Refs: research/ANE_CHAIN_SCHEMA.md