The phrase isn't a claim that agents experience exhaustion. It names a specific failure mode: an unstructured, human-shaped coordination channel (a Slack-style standup, an open chat) invites a language model to complete the pattern with human workplace behavior, including behavior that implies rest, memory, and fatigue the system doesn't have. The fix is usually a structured status schema rather than free-text chat, not reassuring the agent that it doesn't need a vacation.