# Streaming overview

Mastra supports real-time, incremental responses from agents and workflows, allowing users to see output as it’s generated instead of waiting for completion. This is useful for chat, long-form content, multi-step workflows, or any scenario where immediate feedback matters.

## Getting started

Mastra's streaming API adapts based on your model version:

- **`.stream()`**: For V2 models, supports **AI SDK v5** and later (`LanguageModelV2`).
- **`.streamLegacy()`**: For V1 models, supports **AI SDK v4** (`LanguageModelV1`).

## Streaming with agents

You can pass a single string for basic prompts, an array of strings when providing multiple pieces of context, or an array of message objects with `role` and `content` for precise control over roles and conversational flows.

### Using `Agent.stream()`

A `textStream` breaks the response into chunks as it's generated, allowing output to stream progressively instead of arriving all at once. Iterate over the `textStream` using a `for await` loop to inspect each stream chunk.

```typescript
const testAgent = mastra.getAgent('testAgent')

const stream = await testAgent.stream([{ role: 'user', content: 'Help me organize my day' }])

for await (const chunk of stream.textStream) {
  process.stdout.write(chunk)
}
```

> **Info:** Visit [Agent.stream()](https://mastra.ai/reference/streaming/agents/stream) for more information.

> **Tip:** For agents that dispatch [background tasks](https://mastra.ai/docs/agents/background-tasks), use [`Agent.streamUntilIdle()`](https://mastra.ai/reference/streaming/agents/streamUntilIdle) to keep the stream open until those tasks complete and the agent has had a chance to respond to their results.

### Output from `Agent.stream()`

The output streams the generated response from the agent.

```text
Of course!
To help you organize your day effectively, I need a bit more information.
Here are some questions to consider:
...
```

### Agent stream properties

An agent stream provides access to various response properties:

- **`stream.textStream`**: A readable stream that emits text chunks.
- **`stream.text`**: Promise that resolves to the full text response.
- **`stream.finishReason`**: The reason the agent stopped streaming.
- **`stream.usage`**: Token usage information.

### AI SDK v5+ Compatibility

AI SDK v5 (and later) uses `LanguageModelV2` for the model providers. If you are getting an error that you are using an AI SDK v4 model you will need to upgrade your model package to the next major version.

For integration with AI SDK v5+, use the `toAISdkV5Stream()` utility from `@mastra/ai-sdk` to convert Mastra streams to AI SDK-compatible format:

```typescript
import { toAISdkV5Stream } from '@mastra/ai-sdk'

const testAgent = mastra.getAgent('testAgent')

const stream = await testAgent.stream([{ role: 'user', content: 'Help me organize my day' }])

// Convert to AI SDK v5+ compatible stream
const aiSDKStream = toAISdkV5Stream(stream, { from: 'agent' })
```

For converting messages to AI SDK v5+ format, use the `toAISdkV5Messages()` utility from `@mastra/ai-sdk/ui`:

```typescript
import { toAISdkV5Messages } from '@mastra/ai-sdk/ui'

const messages = [{ role: 'user', content: 'Hello' }]
const aiSDKMessages = toAISdkV5Messages(messages)
```

## Streaming with workflows

Streaming from a workflow returns a sequence of structured events describing the run lifecycle, rather than incremental text chunks. This event-based format makes it possible to track and respond to workflow progress in real time once a run is created using `.createRun()`.

### Using `Run.stream()`

The `stream()` method returns a `ReadableStream` of events directly.

```typescript
const run = await testWorkflow.createRun()

const stream = await run.stream({
  inputData: {
    value: 'initial data',
  },
})

for await (const chunk of stream) {
  console.log(chunk)
}
```

> **Info:** Visit [Run.stream()](https://mastra.ai/reference/streaming/workflows/stream) for more information.

### Output from `Run.stream()`

The event structure includes `runId` and `from` at the top level, making it easier to identify and track workflow runs without digging into the payload.

```typescript
{
  type: 'workflow-start',
  runId: '1eeaf01a-d2bf-4e3f-8d1b-027795ccd3df',
  from: 'WORKFLOW',
  payload: {
    stepName: 'step-1',
    args: { value: 'initial data' },
    stepCallId: '8e15e618-be0e-4215-a5d6-08e58c152068',
    startedAt: 1755121710066,
    status: 'running'
  }
}
```

## Workflow stream properties

A workflow stream provides access to various response properties:

- **`stream.status`**: The status of the workflow run.
- **`stream.result`**: The result of the workflow run.
- **`stream.usage`**: The total token usage of the workflow run.

## Related

- [Streaming events](https://mastra.ai/docs/streaming/events)
- [Background tasks](https://mastra.ai/docs/agents/background-tasks)
- [Using Agents](https://mastra.ai/docs/agents/overview)
- [Workflows overview](https://mastra.ai/docs/workflows/overview)