create_task_runner() built TaskRunner's observer/screenshot_provider by
calling describe_screen(device_id)/take_screenshot(device_id) without
manager=, so both silently fell back to the process-global DEFAULT_MANAGER
singleton instead of the Host Agent's real, device-populated DeviceManager.
DEFAULT_MANAGER never has any device registered, so every task's first step
raised DeviceNotFoundError even though the console (which does pass
manager=) showed the same device as connected. Deterministic on every task,
independent of process count.
Add regression tests confirming both lambdas now resolve devices via the
configured manager; verified each fails with the original DeviceNotFoundError
symptom when the fix is reverted.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
q792602257andClaude Sonnet 5
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