# assistant-stream

> Streaming utilities for AI assistants

Latest version **0.3.49** (published 2026-10-09) · MIT license · 0 weekly downloads

## Install

```sh
npm install assistant-stream
pnpm add assistant-stream
yarn add assistant-stream
bun add assistant-stream
```

## Health

**Score 60/100 (C)** — status: active.

Positive: no vulnerabilities; recently updated; high maintenance score; popular repo.

Warnings: low downloads; no types; no esm support; pre 1.0.

## Facts

| | |
|---|---|
| Version | 0.3.49 |
| Published | 2026-10-09 |
| First published | 2024-09-29 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 0 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 12393 |
| Author | AgentbaseAI Inc. |
| Maintainers | yonom, okisdev, agentbase-bot |
| Keywords | ai, streaming, assistant, chat, openai, llm, assistant-ui |

## Links

- npm: https://www.npmjs.com/package/assistant-stream
- Repository: https://github.com/assistant-ui/assistant-ui
- Homepage: https://www.assistant-ui.com/
- Issues: https://github.com/assistant-ui/assistant-ui/issues
- npm.io page: https://npm.io/package/assistant-stream

## Alternatives

- [@expo/fingerprint](https://npm.io/package/@expo/fingerprint.md) — 6.2M weekly downloads
- [@azure/monitor-opentelemetry-exporter](https://npm.io/package/@azure/monitor-opentelemetry-exporter.md) — 850.0K weekly downloads
- [@azure/monitor-opentelemetry](https://npm.io/package/@azure/monitor-opentelemetry.md) — 624.0K weekly downloads
- [@posthog/ai](https://npm.io/package/@posthog/ai.md) — 423.3K weekly downloads
- [fakefilter](https://npm.io/package/fakefilter.md) — 63.9K weekly downloads

## Recent versions

- 0.3.49 (latest) — 2026-10-09
- 0.3.48 — 2026-10-06
- 0.3.47 — 2026-10-06
- 0.3.46 — 2026-10-02
- 0.3.45 — 2026-09-24
- 0.3.44 — 2026-09-18
- 0.3.43 — 2026-09-15
- 0.3.42 — 2026-09-11
- 0.3.41 — 2026-09-03
- 0.3.40 — 2026-08-27
- 0.3.39 — 2026-08-20
- 0.3.38 — 2026-08-18
- 0.3.37 — 2026-08-09
- 0.3.36 — 2026-08-08
- 0.3.35 — 2026-08-08
- … 126 more at https://npm.io/package/assistant-stream/versions

## README

# `assistant-stream`

[![npm version](https://img.shields.io/npm/v/assistant-stream)](https://www.npmjs.com/package/assistant-stream)
[![npm downloads](https://img.shields.io/npm/dm/assistant-stream)](https://www.npmjs.com/package/assistant-stream)
[![bundle size](https://img.shields.io/bundlephobia/minzip/assistant-stream)](https://bundlephobia.com/package/assistant-stream)
[![GitHub stars](https://img.shields.io/github/stars/assistant-ui/assistant-ui)](https://github.com/assistant-ui/assistant-ui)

Framework-agnostic streaming primitives for AI assistant backends. Defines a chunked stream of typed events (text, tool calls, tool results, data parts, message metadata), encoders/decoders for several wire formats, and a server-side tool execution pipeline. Runs in any standard JavaScript runtime; no React or DOM dependencies.

Most apps reach `assistant-stream` indirectly through `@assistant-ui/ai-sdk` or `@assistant-ui/react-data-stream`, which handle the wire format for you. Install it directly when you are building a custom backend or a new integration package.

## Installation

```bash
npm install assistant-stream
```

## Usage

```typescript
import { createAssistantStreamResponse } from "assistant-stream";

export async function POST(request: Request) {
  return createAssistantStreamResponse(async (controller) => {
    controller.appendText("Hello, ");
    controller.appendText("world!");
  });
}
```

`createAssistantStreamResponse` returns a standard Web `Response`, so it works out of the box with any Fetch-style route (Next.js App Router, Hono, Bun.serve, Deno, Cloudflare Workers). Frameworks that use their own response objects (Express, Fastify) need a small adapter: copy `status` and `headers`, then pipe `response.body` into the framework's writable stream. Avoid sending the `Response` body into a `res` object whose lifecycle is already controlled by the framework (that is the `ERR_INVALID_STATE: Controller is already closed` failure mode).

`createAssistantStreamResponse` emits the data stream wire format and sets the
`x-vercel-ai-data-stream: v1` response header. On the frontend,
`useDataStreamRuntime({ api })` detects that marker automatically; pass
`protocol: "data-stream"` only if a custom proxy strips or hides the header.

For tool execution, pipe through `ToolExecutionStream`; for resumable streams (clients can reconnect and replay), import from the `assistant-stream/resumable` sub-path with a `redis` or `ioredis` adapter.

## Sub-paths

`.`, `./utils`, `./ai-sdk`, `./internal`, `./resumable`, `./resumable/redis`, `./resumable/ioredis`. `./ai-sdk` exports `frontendTools`, which converts the tool schemas an assistant-ui client uploads into AI SDK tools; it works with `ai@6` or `ai@7`, install it alongside (declared as an optional peer). `./internal` is an internal-use entry: it is published like every other export, but it only carries the helpers `@assistant-ui/ai-sdk` shares with `./ai-sdk` and is not a supported surface. The two Redis adapters are optional peer dependencies; install whichever client your stack already uses.

Full reference for encoders, tool execution, message conversion, and resumable streams at [assistant-ui.com/docs/architecture](https://www.assistant-ui.com/docs/architecture).

---
_Source: https://npm.io/package/assistant-stream · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._