Distillation

Date: Sep 17, 2026

• 🟡 (09:23) Inspected /tmp/opencode/session-recovery-v22-review/packages/core/src/session/run-coordinator.ts (134 lines), which exports namespace SessionRunCoordinator and defines Coordinator<Key, E> to serialize execution per key while allowing different keys to run concurrently.
• 🟡 (09:23) Coordinator<Key, E> exposes four operations: active snapshots keys owned by the coordinator; run(key) starts execution while idle or joins active execution; wake(key) coalesces one follow-up after newly recorded work; and interrupt(key, cleanup?) stops active execution, runs cleanup, then starts work that arrived while stopping.
• 🟡 (09:23) Entry<E> stores done: Deferred.Deferred<void, E>, optional interruption, optional owner Fiber.Fiber<void, never>, optional Exit.Exit<void, E>, plus pendingWake and stopping booleans; makeEntry() initializes pendingWake: false and stopping: false.
• 🟡 (09:23) SessionRunCoordinator.make() accepts drain(key, force), maintains active entries in Map<Key, Entry<E>>, and runs owner fibers through FiberSet.makeRuntime<never, void, never>().
• 🟡 (09:23) start(key, entry, force, successor) prevents a newly forked non-successor owner from draining until entry.owner has been assigned by waiting on a ready deferred; successor runs instead begin after Effect.yieldNow. The owner invokes options.drain(key, force), calls settle(key, entry, exit) in Effect.onExit, and records itself in entry.owner.
• 🟡 (09:23) settle() saves the owner exit without completing the entry when entry.stopping is true. After a successful non-stopping run with pendingWake, it clears the flag and starts a non-forced successor on the same entry. Otherwise, it either deletes the active key or installs a fresh successor when a wake remains pending, then completes entry.done with the original exit.
• 🟡 (09:23) run(key) uses Effect.uninterruptibleMask: if an entry is active, callers join entry.done; if that entry is stopping, callers wait for entry.done and recursively retry run(key). For an idle key, it creates and registers an entry, starts drain(key, true), and interruptibly awaits completion via restore(...).
• 🟡 (09:23) wake(key) sets pendingWake = true for any existing entry, including one being stopped. For an idle key, it creates an entry and starts drain(key, false).
• 🟡 (09:23) interrupt(key, cleanup = Effect.void) runs cleanup directly when no active owner exists and coalesces concurrent interrupts by awaiting entry.interruption. For a new interruption it sets entry.stopping = true, clears the then-current pendingWake, interrupts the owner fiber, and captures the cleanup exit.
• 🟡 (09:23) After interruption cleanup, interrupt() verifies active.get(key) === entry, requires entry.exit to have been recorded or throws "Interrupted Session execution did not settle", and either deletes the key or creates a non-forced successor when work woke during stopping. It completes entry.done with the interrupted owner’s exit and propagates cleanup failure with Effect.failCause(cleanupExit.cause).
• 🟡 (09:23) The coordinator’s interruption body is uninterruptible and completes the shared entry.interruption deferred from Effect.onExit, allowing all coalesced interruption callers to observe the same cleanup outcome.
• 🟡 (09:23) File discovery found both /tmp/opencode/session-recovery-v22-review/packages/core/src/event.ts and /tmp/opencode/session-recovery-v22-review/packages/core/src/session/event.ts; the latter includes session event definitions such as PromptExecutionRequested, next-step Started/Ended/Failed/Interrupted, tool input events, shell events, compaction events, and revert events.