What
Agent observers (sidecars that monitor running tasks) can now persist across session restarts and reattach to their observed task rather than always spawning fresh.
Details
- Observer state is written to the conversation journal as
"observer-ref"entries containing the observer task ID, agent type, and arming mode. - On a new turn, if a prior observer task ID is found in the journal and the task transcript is still readable, Claude reattaches to the existing observer rather than spawning a new one.
- If the sidecar transcript is unreadable: "[agentObserver] reattach: observer sidecar unreadable — fresh under a new id"
- If the prior observer's agent type doesn't match the declared type, a fresh observer is started.
- Observer teardown now tombstones the sidecar via a
stopped: truejournal entry to prevent reattach loops.
Evidence
Journal type (search for "observer-ref"); reattach log (search for "observer sidecar unreadable")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.