input-required means the agent has paused execution because it needs additional information from the calling agent or user. The agent cannot proceed until the caller sends a follow-up message. This enables multi-turn interactions within a single task.
Description
input-required is the A2A mechanism for conversational and clarification workflows within a single task. The remote agent pauses and signals that it needs more input before proceeding. The original task ID remains the same throughout – this is not a new task.
The caller sends additional information via tasks/send using the same task ID. Once the agent receives the follow-up, it transitions back to working. This state is used for: clarification questions, approval requests, credential prompts, and multi-step form filling.
Clients must handle input-required explicitly. Failing to respond to an input-required state will leave the task stuck indefinitely.