A reasoning-heavy model can burn the whole max_tokens budget on
thinking blocks; the parsed turn then has neither text nor tool calls
and the loop treated it as a successful completion, marking a run done
when nothing happened. Such a first turn now fails the run so the
failure is visible and the heartbeat retries; later empty-text turns
after real tool work still complete normally.
ZacharyZhang-NY
b4e17cbd35