docs/src/content/en/reference/workflows/run-methods/start.mdx
The .start() method starts a workflow run with input data, allowing you to execute the workflow from the beginning.
const run = await workflow.createRun()
const result = await run.start({
inputData: {
value: 'initial data',
},
})
<PropertiesTable content={[ { name: 'inputData', type: 'z.infer<TInput>', description: "Input data that matches the workflow's input schema", isOptional: true, }, { name: 'requestContext', type: 'RequestContext', description: 'Request Context data to use during workflow execution', isOptional: true, }, { name: 'outputWriter', type: '(chunk: TOutput) => Promise<void>', description: 'Optional asynchronous function to handle output chunks as they are produced', isOptional: true, }, { name: 'tracingContext', type: 'TracingContext', isOptional: true, description: "Tracing context for creating child spans and adding metadata. Automatically injected when using Mastra's tracing system.", properties: [ { parameters: [ { name: 'currentSpan', type: 'Span', isOptional: true, description: 'Current span for creating child spans and adding metadata. Use this to create custom child spans or update span attributes during execution.', }, ], }, ], }, { name: 'tracingOptions', type: 'TracingOptions', isOptional: true, description: 'Options for Tracing configuration.', properties: [ { parameters: [ { name: 'metadata', type: 'Record<string, any>', isOptional: true, description: 'Metadata to add to the root trace span. Useful for adding custom attributes like user IDs, session IDs, or feature flags.', }, ], }, { parameters: [ { name: 'requestContextKeys', type: 'string[]', isOptional: true, description: "Additional RequestContext keys to extract as metadata for this trace. Supports dot notation for nested values (e.g., 'user.id').", }, ], }, { parameters: [ { name: 'traceId', type: 'string', isOptional: true, description: 'Trace ID to use for this execution (1-32 hexadecimal characters). If provided, this trace will be part of the specified trace.', }, ], }, { parameters: [ { name: 'parentSpanId', type: 'string', isOptional: true, description: 'Parent span ID to use for this execution (1-16 hexadecimal characters). If provided, the root span will be created as a child of this span.', }, ], }, { parameters: [ { name: 'tags', type: 'string[]', isOptional: true, description: 'Tags to apply to this trace. String labels for categorizing and filtering traces.', }, ], }, ], }, { name: 'outputOptions', type: 'OutputOptions', isOptional: true, description: 'Options for output configuration.', properties: [ { parameters: [ { name: 'includeState', type: 'boolean', isOptional: true, description: 'Whether to include the workflow run state in the result.', }, ], }, ], }, ]} />
<PropertiesTable content={[ { name: 'result', type: 'Promise<WorkflowResult<TState, TOutput, TSteps>>', description: 'A promise that resolves to the workflow execution result containing step outputs and status', }, { name: 'traceId', type: 'string', isOptional: true, description: 'The trace ID associated with this execution when Tracing is enabled. Use this to correlate logs and debug execution flow.', }, { name: 'spanId', type: 'string', isOptional: true, description: 'The root span ID associated with this execution when Tracing is enabled. Use this for span-level lookup and correlation.', }, ]} />
import { RequestContext } from '@mastra/core/request-context'
const run = await workflow.createRun()
const requestContext = new RequestContext()
requestContext.set('variable', false)
const result = await run.start({
inputData: {
value: 'initial data',
},
requestContext,
})