Both `AgentSession.#emit` (session/agent-session.ts) and `Agent.#emit`
(packages/agent/src/agent.ts) iterated listeners with no error isolation.
A synchronous throw in any subscriber aborted the for-loop, so later
subscribers (TUI rendering, ACP bridge, task executor progress,
hindsight) silently missed events. Many listeners — see
`modes/controllers/event-controller.ts:141` and
`modes/controllers/input-controller.ts:576` — are registered as
`async (event) => { await this.handleEvent(event); }`; the returned
Promise was dropped, so any rejection became an unhandled rejection.
Wrap each listener invocation in try/catch and attach a `.catch` to any
returned thenable. Errors are logged via `logger.warn` (already imported
in agent-session.ts) and `console.error` (agent.ts has no logger
dependency, keep it that way).
Test: new `test/session/emit-listener-isolation.test.ts` registers two
listeners on both classes; first listener throws (or returns a rejecting
Promise); asserts the second listener still receives the event AND no
`unhandledRejection` fires. 4 cases (sync+async × Agent+AgentSession).
All fail on current main; all pass with the fix.
- Added optional `onBeforeYield` configuration and `setOnBeforeYield` in Agent, executed before follow-up checks.
- Added `YieldQueue` to `AgentSession`, with setup/teardown and streaming/idle flush via `setOnBeforeYield`.
- Replaced immediate async-result follow-up dispatch with queued batch entries, including stale-state suppression.
- Added MCP follow-up queueing in SDK, deduplicating updates by `serverName` and `uri`.
- Added changelog entries for `onBeforeYield`, async-result batching, MCP dedupe, and `display.shimmer` modes.
- Added yield queue unit tests for streaming emission, debounced idle batches, stale filtering, and error isolation.
oldschoola