Anvia Docs

Use .stream() when the UI needs incremental text or when you want to observe tool calls as they happen.

Basic 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 model must support streaming. If the selected completion model does not support streaming, Anvia throws before the run starts.

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

Streaming With Tools

Tool workflows can span multiple model turns.

for await (const event of agent.prompt("Where is order A-100?").stream()) {
  if (event.type === "tool_call") {
    console.log("tool", event.toolCall.function.name);
  }

  if (event.type === "tool_result") {
    console.log("result", event.result);
  }

  if (event.type === "final") {
    console.log(event.output);
  }
}

The final event contains the same shape you get from .send(): output, usage, messages, and trace metadata.

Readable Streams

Convert async iterable events to newline-delimited JSON when you need a web stream.

import { toReadableStream } from "@anvia/core";

const stream = toReadableStream(agent.prompt("Draft a reply.").stream());

This is useful for HTTP responses, server functions, and UI frameworks that consume ReadableStream.