Architecture · 11.03
The EventBus: What's Happening Now
The realtime publish bridge for workspace, run, and workflow rooms, and why subscribe-before-read is the rule.
The complement to the ledger, not a duplicate of it
Where the ledger is the durable record of what already happened, the EventBus is the live bridge for what's happening right now — publishing into workspace, run, and workflow rooms after JWT validation, so a connected client hears about a state change the moment it occurs rather than discovering it on the next poll.
The standing rule across every subsystem that uses it: subscribe to a room before reading current state, never after. Reading state first and subscribing second leaves a real window where an event can fire in between — and get missed entirely. The event-driven agentis.run.await is built directly on this discipline: it joins the run's room first, then checks whether the run has already settled, so a run that finishes in the split second between the check and the subscribe still can't be missed.