Browse documentation
A2A binding
Carry AQP as an A2A extension linked to tasks, messages, and artifacts.
Advertisement
An A2A Agent Card advertises https://agentqueryprotocol.com/extensions/2026-07-30/a2a and declares whether it can request, respond to, collect, or relay AQP objects.
Request
A server agent attaches a canonical QueryRequest as a structured-data Part on a Message or Artifact. The subject should include the A2A contextId, taskId, and, when applicable, artifactId.
Response
The respondent agent sends a new Message or Task containing the canonical response. When the collector is a separate A2A agent, the query provides its discovery location and a scoped capability.
Task lineage
A completed A2A task remains immutable. Answers, corrections, and refinements therefore create new messages or tasks in the same context and reference the original task rather than mutating it.