Pre-Release Review of a Concurrency Feature

A multi-operator time-tracking feature: one operator is primary on a task, and others join as companions. I reviewed it before it was built.

1. A stop action that reverted the stage and closed companion sessions without a transaction. A failure partway through would leave the data half-updated.

2. A role computed from live session data on every load, with no lock. Two people joining together could both become primary.

3. No test for the primary operator leaving.

4. A UI flash while loading.

5. An unvalidated role field.

6. A product question about hiding the complete button.

Run the stop action in one transaction.

Assign the role once, at join time, with a constraint allowing one active primary per task.

Validate the role field against a schema, show a pending state while loading, and get product sign-off on the complete button.

An AI-assisted first pass against the brief, then my own judgment and ranking of every concern.

Every concern was raised before implementation.