The blocking gateway approval wait at tools/approval.py called
`entry.event.wait(timeout=...)` which never touched the agent's
activity tracker. When a user was slow to respond to a /approve prompt
(or the gateway_timeout config was set higher than the default 300s),
the agent thread sat silent long enough for the gateway's inactivity
watchdog (agent.gateway_timeout, default 1800s) to kill it — even
though the agent was doing exactly the right thing and the user was
the one causing the delay.
The fix polls the event in 1s slices and calls touch_activity_if_due
between slices, mirroring the _wait_for_process() pattern in
tools/environments/base.py that covers the subprocess-waiting side of
the same problem. At the default 10s heartbeat cadence, a 300s
approval wait now pings activity ~30 times, well under the 1800s
idle threshold.
Observed in community user logs: 12 repeated 'Agent idle 1800s,
last_activity=executing tool: terminal' events across April 12-14.
Companion to PR #10501 which covered streaming / concurrent-tool /
Modal-backend gaps but did not touch approval.py.
Test: tests/tools/test_approval_heartbeat.py — verifies (1) heartbeats
fire during the wait, (2) user responses are still near-instant, and
(3) the approval path stays functional when the heartbeat helper
can't be imported.
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