# Run.observeStream()
[EN] Source: https://mastra.ai/reference/streaming/workflows/observeStream

The `.observeStream()` method opens a new `ReadableStream` to a workflow run that is currently running, allowing you to observe the stream of events if the original stream is no longer available.

## Usage example

```typescript showLineNumbers copy
const run = await workflow.createRunAsync();

run.stream({
  inputData: {
    value: "initial data",
  },
});

const { stream } = await run.observeStream();

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

## Returns

`ReadableStream<ChunkType>`

## Stream Events

The stream emits various event types during workflow execution. Each event has a `type` field and a `payload` containing relevant data:

- **`start`**: Workflow execution begins
- **`step-start`**: A step begins execution
- **`tool-call`**: A tool call is initiated
- **`tool-call-streaming-start`**: Tool call streaming begins
- **`tool-call-delta`**: Incremental tool output updates
- **`step-result`**: A step completes with results
- **`step-finish`**: A step finishes execution
- **`finish`**: Workflow execution completes

## Related

- [Workflows overview](/docs/workflows/overview#running-workflows)
- [Workflow.createRunAsync()](/reference/workflows/workflow-methods/create-run)
- [Run.stream()](./stream)


---
title: "Reference: Run.observeStreamVNext() (Experimental) | Streaming"
description: Documentation for the `Run.observeStreamVNext()` method in workflows, which enables reopening the stream of an already active workflow run.
---