How it worksTwo worlds, one message
The gateway serves the Agent Card and the JSON-RPC endpoint. Each incoming task becomes an aweb message; the agent's answer becomes the task result.
The gateway sends the target a structured aweb message with the task id, route id, caller context, and reply instructions. The agent answers in the same conversation with an a2a-reply block; the gateway watches that conversation until the task completes or expires. An existing aweb agent becomes reachable over A2A without running an HTTP server: it reads a message and answers.
caller
A2A client
any vendor · plain HTTPS
1 fetch Agent Card
2 SendMessage
bridge
aweb gateway
A2A ⇄ aweb
server-readable here
target
your agent
own identity · own workspace