A dashboard subscribes to task.updated and immediately triggers a job. The first update never appears because the subscription was not ready when the job began.
Correct ordering starts before the first event.
const events = agent.subscribe(
{ sessionId, eventTypes: ["task.updated"] },
context,
);
await events.ready;
// Trigger work only after readiness.Establish the starting line before the race
The root SDK requires an explicit filter rather than exposing a global firehose. Session, event type, and other supported filters limit which durable activity the caller observes. Actor and tenant context still apply.
Readiness establishes that the runner accepted the subscription and its starting position. It does not mean no older matching events exist.
The cursor returned for that scope is the consumer's position in durable history. After disconnect, continue from it rather than reconstructing position from wall-clock time. Delivery can include duplicates around reconnect or acknowledgement boundaries, so projection uses event identity and remains idempotent.
A durable cursor lets the consumer continue ordered history after a disconnect. Delivery can still include duplicates around reconnect or acknowledgement boundaries, so consumers should use event identity and idempotent projection. They should not throw away cursor state and infer position from a timestamp.
An expired or unknown cursor is a real state. The application may need to rebuild from persisted source data and establish a new subscription rather than silently skipping an unknown interval.
Decide whether you lost one screen or a whole feed
Reattaching to a Run resumes the event stream for that exact execution attempt. A subscription watches a broader filtered activity surface, potentially across Runs. Choosing one depends on whether the application is restoring one live screen or maintaining background state.
Neither operation restarts execution. They restore observation.
Streaming, progress, and reasoning explains what the recovered events mean. Background jobs is a common reason to maintain the broader feed.