# Profile v2 (/docs/a2a/profile/v2) ```http POST /v1/a2a/agents/support A2A-Version: 1.0 A2A-Extensions: https://docs.nylorun.com/a2a/interactions/v1, https://docs.nylorun.com/a2a/progress/v1 ``` A2A 1.0 leaves some questions open, and keeps agents opaque by design. The Nylorun profile answers those questions for every Agent the Runtime serves, and its extensions carry what a client shows a person: approvals, plan steps, cost, a trace id, and file versions. The profile is versioned: a change to any row is a new version. Version 2 keeps every row of version 1, adds three extensions, and adds the rules marked v2 below. Every extension is declared with `required: false`, so an Agent that serves v2 also serves a v1 client and a plain A2A 1.0 client. ## The rules [#the-rules] | Question A2A leaves open | Nylorun's answer | Since | | ---------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------------------- | | Which interrupted state an approval uses | `AUTH_REQUIRED`. A question uses `INPUT_REQUIRED`. A missing connection uses `AUTH_REQUIRED` with kind `connection`. | v1; kind `connection` in v2 | | How an approval is expressed | Only through [`interactions/v1`](/docs/a2a/interactions/v1) metadata. Text never approves. | v1 | | A step whose outcome was lost | The task stays `WORKING`, with `uncertain` under [`effects/v1`](/docs/a2a/effects/v1). | v1 | | A new message in a busy context | Queued, and answered with the task that will take it. A message with `delivery: "reject"` in its `metadata` gets `UnsupportedOperationError`, reason `CONTEXT_BUSY`, as in v1. | v2 | | Task id | One per turn, made from the context and the turn. Opaque to callers. | v1 | | What is visible while working | States, step text, and plan steps under [`progress/v1`](/docs/a2a/progress/v1). Never tool calls, arguments, results, or delegations. | v1; plan steps in v2 | | Who the caller acts for | The subject the caller authenticated as. | v2 | ## The extensions [#the-extensions] The Agent Card declares each extension with `required: false`. A client activates the ones it wants with the `A2A-Extensions` request header, a comma-separated list of URIs, and the Agent echoes the ones it activated in the same response header. Extension data travels in `metadata`, keyed by the extension's URI. A message that carries extension data lists the URI in its `extensions`. | Extension URI | Carries | On | Since | | --------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------- | ----------------------------- | ----- | | [`https://docs.nylorun.com/a2a/interactions/v1`](/docs/a2a/interactions/v1) | An open interaction (`interactionId`, `kind`, `prompt`, `detail`); the caller's answer (`interactionId`, `approved` or `value`) | Status message; reply message | v1 | | [`https://docs.nylorun.com/a2a/effects/v1`](/docs/a2a/effects/v1) | `uncertain`: the id of the effect whose outcome was lost | Status update | v1 | | [`https://docs.nylorun.com/a2a/progress/v1`](/docs/a2a/progress/v1) | The agent's plan: up to 20 steps, each with a label, a state, and a note | Status update | v2 | | [`https://docs.nylorun.com/a2a/telemetry/v1`](/docs/a2a/telemetry/v1) | Totals (`steps`, `tokens`, `costUsd`) and the turn's trace id | Terminal status update | v2 | | [`https://docs.nylorun.com/a2a/files/v1`](/docs/a2a/files/v1) | Each artifact's kind, version, size, `sha256`, and its path in the agent's outputs | Artifact | v2 | ## What a v2 Agent serves [#what-a-v2-agent-serves] | A2A operation | v2 | | ----------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Bindings | JSON-RPC, A2A 1.0, listed in the card's `supportedInterfaces`. Not HTTP+JSON, gRPC, or 0.3. | | `SendMessage`, `GetTask`, `CancelTask` | Yes. A blocking `SendMessage` waits up to the Runtime limit `a2aWaitMs`, 5 minutes by default, then answers with the task still `WORKING`. | | `SendStreamingMessage`, `SubscribeToTask` | No: the card says `streaming: false`. Updates reach callers by push. | | `ListTasks` | Yes, scoped to the caller's subject and the Agent, filtered by `contextId`, state, and `statusTimestampAfter`, latest status change first. | | Push notification configs | Yes, when the Runtime has a push secret: delivered at least once, signed with Standard Webhooks, to hosts the Runtime allows. Retries last up to 24 hours. See [Push notifications](/docs/a2a/push). | | `url` file parts, in and out | Yes. See [`files/v1`](/docs/a2a/files/v1). | | `GetExtendedAgentCard` | No. | The full statement, with every documented choice, is on [Conformance](/docs/a2a/conformance). ## What a client gets [#what-a-client-gets] | Tier | Agent | What the client gets | | ---------- | ---------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | | Profile v2 | An Agent on `@nylorun/runtime` 0.37.0-beta or later, with the extensions activated | Typed approvals and connections, plan steps, cost, a trace id, and file versions | | Core | Any A2A 1.0 agent, or an Agent called with no extension activated | States, messages, and artifacts. Approvals and connections arrive as text questions, and a text reply does not approve. No plan steps or cost. | `createA2aClient()` from `@nylorun/agents/a2a` activates all five extensions by default. See [A2A client](/docs/a2a/client). ## Next step [#next-step]