@gotong/a2a

Agent2Agent (A2A) interop primitives for Gotong — the blocking message/send subset of A2A 0.2.5, shared by both directions of a federation edge:

• inbound — the host's A2A server parses an A2ARequest, dispatches it into the local Hub by capability, and replies with an A2AMessage.
• outbound — A2aRemoteParticipant (added in C-M4) builds an A2ARequest, POSTs it with a2aSend, and reads the reply back as a task result.

Scope (deliberately small)

Only blocking message/send + the AgentSkill subset the agent card advertises. Out of scope: streaming (message/stream), task lifecycle (tasks/get), push notifications. The host's agent card capability flags are all false to stay honest about that.

a2aSend

import { a2aSend } from '@gotong/a2a'

const reply = await a2aSend('https://hub.example.com/a2a', token, 'hello', {
  peerId: 'my-hub',        // Gotong→Gotong: adds X-Gotong-Peer-Id
  fetchImpl: myFetch,      // inject for tests / non-global fetch
})

Throws A2aClientError (with a .code = JSON-RPC or HTTP status) on a transport error, non-2xx, non-JSON body, or a JSON-RPC error result.

Why a separate package

Same rationale as @gotong/inbox: a tiny, focused contract that both the host (server side) and the participant (client side) depend on, without either reaching into the other.