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Step Class

The Step class defines individual units of work within a workflow, encapsulating execution logic, data validation, and input/output handling. It can take either a tool or an agent as a parameter to automatically create a step from them.

Usage example​

import { createWorkflow, createStep } from "@mastra/core/workflows";
import { z } from "zod";

const step1 = createStep({
  id: "step-1",
  description: "passes value from input to output",
  inputSchema: z.object({
    value: z.number(),
  }),
  outputSchema: z.object({
    value: z.number(),
  }),
  execute: async ({ inputData }) => {
    const { value } = inputData;
    return {
      value,
    };
  },
});

Constructor Parameters​

id:

string
Unique identifier for the step

description:

string
Optional description of what the step does

inputSchema:

z.ZodType<any>
Zod schema defining the input structure

outputSchema:

z.ZodType<any>
Zod schema defining the output structure

resumeSchema:

z.ZodType<any>
Optional Zod schema for resuming the step

suspendSchema:

z.ZodType<any>
Optional Zod schema for suspending the step

stateSchema:

z.ZodObject<any>
Optional Zod schema for the step state. Automatically injected when using Mastra's state system. The stateSchema must be a subset of the workflow's stateSchema. If not specified, type is 'any'.

execute:

(params: ExecuteParams) => Promise<any>
Async function containing step logic

ExecuteParams​

inputData:

z.infer<TStepInput>
The input data matching the inputSchema

resumeData:

z.infer<TResumeSchema>
The resume data matching the resumeSchema, when resuming the step from a suspended state. Only exists if the step is being resumed.

mastra:

Mastra
Access to Mastra services (agents, tools, etc.)

getStepResult:

(step: Step | string) => any
Function to access results from other steps

getInitData:

() => any
Function to access the initial input data of the workflow in any step

suspend:

() => Promise<void>
Function to pause workflow execution

setState:

(state: z.infer<TState>) => void
Function to set the state of the workflow. Inject via reducer-like pattern, such as 'setState({ ...state, ...newState })'

runId:

string
Current run id

runtimeContext?:

RuntimeContext
Runtime context for dependency injection and contextual information.

runCount?:

number
The run count for this specific step, it automatically increases each time the step runs