DevelopersEvent stream
The stream is not model output. It is the execution itself, event by event: the plan, every action the runtime admits, the terminal state. Native tools are reported as categories, never concrete ids. Your client tools keep their real name and args.
run
{ run_id }
First frame: the id of this run, also visible in the dashboard.
plan
{ items }
The full plan, emitted up front.
plan_item_start
{ num, def }
Each step as the plan advances.
action
{ tool }
A capability the agent used. Native tools surface as categories ("fetching from the web"), never concrete ids.
tool_request
{ call_id, tool, args }
The agent calls one of YOUR tools. The SDK runs it locally and replies for you.
done
{ result }
End condition met, the stream closes.
fatal
{ semantic }
The run aborted. Only the failure category is exposed.