translation/source/documents/course/04-workflows/02-understanding-steps.md

Understanding Steps

Steps are the building blocks of workflows. Each step is a self-contained unit that takes some input, processes it, and produces an output.

What is a Step?

A step has three main parts:

1. Input Schema - what data it expects to receive
2. Output Schema - what data it will produce
3. Execute Function - the logic that transforms input to output

Step Structure

Every step follows this pattern:

const myStep = createStep({
  id: "unique-step-name",
  description: "What this step does",
  inputSchema: z.object({
    // Define expected input structure
  }),
  outputSchema: z.object({
    // Define output structure
  }),
  execute: async ({ inputData }) => {
    // Your logic here
    return {
      // Return data matching output schema
    };
  },
});

Why Use Schemas?

Schemas provide several benefits:

• Type Safety: TypeScript knows exactly what data flows between steps
• Runtime Validation: Invalid data is caught immediately with helpful error messages
• Documentation: Schemas serve as living documentation of your workflow
• Debugging: Clear contracts make it easy to identify issues

Key Benefits

• Reusable: Steps can be used in multiple workflows
• Testable: Each step can be tested in isolation
• Composable: Steps can be combined in different ways
• Reliable: Schemas catch data flow issues early
• Traceable: Every step is traced so you can see the flow of data

Next, you'll create your first step!