A2A Protocol

Agent-to-Agent (A2A) protocol endpoints for interoperability with external A2A clients. Exposes agent discovery via Agent Cards, and message-driven Tasks scoped to a session.

📄️Get A2A agent card (well-known)

Returns the A2A v0.3 [Agent Card](https://a2a-protocol.org) for the specified agent at the canonical `.well-known/agent-card.json` discovery URL. Standard A2A clients fetch this URL, then use the card's `url` and `preferredTransport` to drive subsequent calls.

📄️Get A2A agent card (v0.3 RPC)

Returns the same v0.3 Agent Card as `.well-known/agent-card.json`, served at the v0.3 RPC URL `GET /v1/card`.

📄️Send A2A v0.3 message

Sends a message to the agent. Blocks until the agent reaches a terminal or interrupted state. Returns the resulting `task`, or a direct `message` reply for stateless interactions.

📄️Send A2A v0.3 streaming message

Sends a message to the agent and streams task lifecycle events as Server-Sent Events. Each SSE `data:` line is a JSON `A2aV03StreamResponse` carrying a `task`, `message`, `statusUpdate`, or `artifactUpdate`. The stream ends when the task reaches a terminal or interrupted state.

📄️Get A2A v0.3 task

Returns the current state of an A2A task, including its status, conversation history, and any produced artifacts.

📄️Cancel A2A v0.3 task

Cancels a running task. Returns the canonical state of the task after cancellation. If the task is already terminal, returns `409`.

📄️Subscribe to A2A v0.3 task updates

Attaches to a running task and streams subsequent lifecycle updates as Server-Sent Events. If the task is already terminal, streams the final task and closes.

📄️Get A2A v1 agent card (well-known)

Returns the v1 [Agent Card](https://a2a-protocol.org) at the well-known discovery URL `/.well-known/a2a/v1/agent-card.json`. The card lists every supported transport in `supportedInterfaces` (the first entry is preferred). v1 clients discover this URL and pick a binding from the list.

📄️Send A2A v1 message

Sends a message to the agent using the A2A v1 wire format. Blocks until the agent reaches a terminal or interrupted state. Returns the resulting `task`, or a direct `message` reply for stateless interactions.

📄️Send A2A v1 streaming message

Sends a message to the agent using the A2A v1 wire format and streams task lifecycle events as Server-Sent Events. Each SSE `data:` line is a JSON `A2aV1StreamResponse` carrying a `task`, `message`, `statusUpdate`, or `artifactUpdate`. The stream ends when the task reaches a terminal or interrupted state.

📄️Get A2A v1 task

Returns the current state of an A2A task in the v1 wire format, including its status, conversation history, and any produced artifacts.

📄️Cancel A2A v1 task

Cancels a running task. Returns its state after cancellation in the v1 wire format. Returns `409` if the task is not currently running.

📄️Subscribe to A2A v1 task updates

Attaches to a running task and streams subsequent lifecycle updates as Server-Sent Events in the v1 wire format. If the task is already terminal, streams the final task and closes.

📄️Get A2A v1 extended agent card

Returns the v1 [Agent Card](https://a2a-protocol.org) for authenticated callers. The response body is identical to the well-known v1 card.

📄️List A2A v1 tasks

Lists the agent's tasks. Results are paginated. Optional query parameters filter by conversation context and lifecycle state.