Anvia Docs

Use .stream() when your UI, worker, or API route needs incremental updates instead of waiting for the final response.

1. Start a Stream

for await (const event of agent.prompt("Write a short reply.").stream()) {
  if (event.type === "text_delta") {
    process.stdout.write(event.delta);
  }
}

The agent's completion model must support streaming. If the model does not support streaming, Anvia throws before the run starts.

2. Handle the Core Events

for await (const event of agent.prompt("Where is order A-100?").stream()) {
  switch (event.type) {
    case "text_delta":
      process.stdout.write(event.delta);
      break;
    case "tool_call":
      console.log("tool_call", event.toolCall.function.name);
      break;
    case "tool_result":
      console.log("tool_result", event.toolName, event.result);
      break;
    case "final":
      console.log("done", event.output);
      break;
  }
}

3. Know the Event Order

Most text-only runs look like this:

turn_start
text_delta
text_delta
turn_end
final

Tool runs can span multiple turns:

turn_start
tool_call
turn_end
tool_result
turn_start
text_delta
turn_end
final

4. Event Types

Event	Meaning
`turn_start`	A model turn is starting
`text_delta`	Assistant text arrived
`reasoning_delta`	Reasoning text arrived from a provider that exposes it
`tool_call`	The model requested a tool
`tool_result`	Anvia ran a tool and produced a result
`tool_approval_request`	A guarded tool needs approval
`tool_approval_result`	Approval was resolved
`turn_end`	A model turn ended
`final`	The agent run completed
`error`	The stream failed

The final event contains the same important data as .send(): output, usage, messages, and optional trace.

Streaming Events

1. Start a Stream

2. Handle the Core Events

3. Know the Event Order

4. Event Types