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ReferenceWorkflowsMethods.streamVNext()

Run.streamVNext()

The .streamVNext() method enables real-time streaming of responses from a workflow.

Usage example

const run = await workflow.createRunAsync();
 
const stream = run.streamVNext({
  inputData: {
    value: "initial data",
  },
});

Parameters

inputData?:

z.infer<TInput>
Input data that matches the workflow's input schema

runtimeContext?:

RuntimeContext
Runtime context data to use during workflow execution

Returns

stream:

MastraWorkflowStream<ChunkType>
A custom stream that extends ReadableStream<ChunkType> with additional workflow-specific properties

stream.status:

Promise<RunStatus>
A promise that resolves to the current workflow run status

stream.result:

Promise<WorkflowResult<TOutput, TSteps>>
A promise that resolves to the final workflow result

stream.usage:

Promise<{ promptTokens: number; completionTokens: number; totalTokens: number }>
A promise that resolves to token usage statistics

Extended usage example

const run = await workflow.createRunAsync();
 
const stream = run.streamVNext({
  inputData: {
    value: "initial data",
  },
});
 
const result = await stream.result;

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
  • step-output: Custom output from a step
  • step-result: A step completes with results
  • finish: Workflow execution completes with usage statistics
.stream().watch()