> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentium.in/llms.txt
> Use this file to discover all available pages before exploring further.

# A2A 1.0

> Expose authenticated A2A tasks with verified ownership and a bounded process-local lifecycle.

`createA2AV1Server` from `@agentium/transport` and `A2AV1Client` from `@agentium/core` use A2A 1.0. Install the optional `@a2a-js/sdk` peer; the working-tree fixtures use 1.3.0.

The server exposes JSON-RPC and `/.well-known/agent-card.json`. Configure `agents`, the public `url`, an explicit `audience`, and an `authenticate(request, audience)` callback. The callback verifies credentials and returns `{ tenantId, userId }` from trusted claims.

## Task ownership

Verified tenant and actor own tasks. Request-body tenant overrides cannot change identity. Tasks accept text, structured JSON, and supported image parts. Structured Agent results become typed artifacts. The optional `completionState` callback maps application results to input-required or authentication-required interruptions.

Cancellation waits for owned Agent work to settle; a noncooperative callback can delay it. Late success cannot overwrite a canceled result. Capacity is bounded before admission and in the backing store, with one active writer per identity/session.

This server's task history is process-local and resets on restart. Use [durable A2A](/durable/protocols) for a separately configured durable supervisor and host admission contract.

## Client transport

`A2AV1Client({ url, headers, timeoutMs })` restricts credential-bearing discovery and requests to the configured origin, rejects redirects, and supports per-call cancellation while sharing discovery. The host remains responsible for remote media access policy in its model adapter.

## Migrate legacy endpoints

`createA2AServer`, `A2ARemoteAgent`, `A2ARemoteTeam`, and `A2ARemoteWorkflow` retain the older protocol. Mount legacy endpoints separately during migration. Redundant `createA2ALegacyServer` and `A2ALegacyRemoteAgent` aliases are removed.

Legacy clients propagate cancellation and release stream readers on early exit. Legacy authentication and task-owner isolation remain host middleware responsibilities; they do not inherit the v1 server's ownership contract.


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