Convert Flow Workflow Definition to Output SDK

Overview

This skill guides the conversion of Flow SDK workflow classes to Output SDK functional workflow definitions. Workflows orchestrate step execution and define the overall data flow.

When to Use This Skill

During Migration:

• Converting workflow.ts from class-based to functional
• Setting up workflow input/output schemas
• Updating step invocation patterns

Key Differences

Aspect	Flow SDK	Output SDK
Definition	Class with execute() method	workflow() function
Input/Output	TypeScript interfaces	Zod schemas
Activity Calls	Direct function calls	Step calls with object params
Error Handling	Try-catch blocks	Let errors propagate
Imports	@flow/sdk	@output.ai/core

Conversion Pattern

Flow SDK Workflow (Before)

// workflow.ts
import { Workflow, WorkflowScope } from '@flow/sdk';
import { fetchUser, processData, saveResults } from './activities';

interface WorkflowInput {
  userId: string;
  processType: string;
}

interface WorkflowOutput {
  success: boolean;
  resultId: string;
}

export class DataProcessingWorkflow implements Workflow<WorkflowInput, WorkflowOutput> {
  async execute( input: WorkflowInput ): Promise<WorkflowOutput> {
    try {
      // Get user data
      const user = await fetchUser( input.userId );

      // Process the data
      const processed = await processData( user, input.processType );

      // Save results
      const result = await saveResults( processed );

      return {
        success: true,
        resultId: result.id
      };
    } catch ( error ) {
      throw new Error( `Workflow failed: ${error.message}` );
    }
  }
}

Output SDK Workflow (After)

// workflow.ts
import { workflow, z } from '@output.ai/core';
import { fetchUser, processData, saveResults } from './steps.js';

const WorkflowInputSchema = z.object( {
  userId: z.string(),
  processType: z.string()
} );

const WorkflowOutputSchema = z.object( {
  success: z.boolean(),
  resultId: z.string()
} );

export default workflow( {
  name: 'dataProcessing',
  description: 'Process user data and save results',
  inputSchema: WorkflowInputSchema,
  outputSchema: WorkflowOutputSchema,
  fn: async ( input ) => {
    // Get user data
    const user = await fetchUser( { userId: input.userId } );

    // Process the data
    const processed = await processData( { user, processType: input.processType } );

    // Save results
    const result = await saveResults( { data: processed } );

    return {
      success: true,
      resultId: result.id
    };
  }
} );

Step-by-Step Conversion Process

Step 1: Identify Workflow Class

Find the workflow class in workflow.ts:

grep -E "class.*Workflow" src/workflows/my-workflow/workflow.ts

Step 2: Extract Input/Output Types

Convert TypeScript interfaces to Zod schemas:

// Before: TypeScript interface
interface WorkflowInput {
  userId: string;
  count: number;
  options?: ProcessOptions;
}

// After: Zod schema
const WorkflowInputSchema = z.object( {
  userId: z.string(),
  count: z.number(),
  options: ProcessOptionsSchema.optional()
} );

Step 3: Convert Class to Function

Replace class definition with workflow() call:

// Before
export class MyWorkflow implements Workflow<Input, Output> {
  async execute( input: Input ): Promise<Output> {
    // ...
  }
}

// After
export default workflow( {
  name: 'myWorkflow',
  description: 'Description of what this workflow does',
  inputSchema: InputSchema,
  outputSchema: OutputSchema,
  fn: async ( input ) => {
    // ...
  }
} );

Step 4: Update Step Invocations

Change direct function calls to object parameter calls:

// Before (Flow SDK)
const result = await someActivity( param1, param2, param3 );

// After (Output SDK)
const result = await someStep( { param1, param2, param3 } );

Step 5: Remove Try-Catch Blocks

Remove error handling wrappers (see flow-error-try-catch-removal):

// Before
async execute( input ) {
  try {
    const result = await doWork( input );
    return result;
  } catch ( error ) {
    throw new Error( error.message );
  }
}

// After
fn: async ( input ) => {
  const result = await doWork( { ...input } );
  return result;
}

Step 6: Update Imports

// Before
import { Workflow, WorkflowScope } from '@flow/sdk';
import { z } from 'zod';

// After
import { workflow, z } from '@output.ai/core';

Important Conventions

1. Workflow Naming

The workflow name must match the legacy name if other systems depend on it:

// Legacy system calls workflow by name 'userOnboarding'
export default workflow( {
  name: 'userOnboarding',  // Must match!
  // ...
} );

2. Default Export

Workflows should use export default:

// CORRECT
export default workflow( { ... } );

// WRONG
export const myWorkflow = workflow( { ... } );

3. File Extension in Imports

Always include .js extension for local imports:

import { fetchUser, processData } from './steps.js';
import { WorkflowInputSchema } from './types.js';

Child Workflows

Workflows can invoke other workflows directly:

// parent/workflow.ts
import { workflow, z } from '@output.ai/core';
import childWorkflow from '../child/workflow.js';

export default workflow( {
  name: 'parentWorkflow',
  inputSchema: z.object( { data: z.string() } ),
  outputSchema: z.object( { result: z.string() } ),
  fn: async ( input ) => {
    // Call child workflow like a step
    const childResult = await childWorkflow( { input: input.data } );

    return { result: childResult.output };
  }
} );

Complete Migration Example

Before: Flow SDK

// workflow.ts
import { Workflow, WorkflowScope, FatalError } from '@flow/sdk';
import {
  validateInput,
  fetchUserProfile,
  generateReport,
  sendNotification
} from './activities';

interface ReportInput {
  userId: string;
  reportType: 'daily' | 'weekly' | 'monthly';
  includeCharts: boolean;
}

interface ReportOutput {
  reportId: string;
  downloadUrl: string;
  generatedAt: string;
}

export class GenerateReportWorkflow implements Workflow<ReportInput, ReportOutput> {
  async execute( input: ReportInput ): Promise<ReportOutput> {
    try {
      // Validate input
      const validated = await validateInput( input );

      // Fetch user profile
      const profile = await fetchUserProfile( input.userId );

      // Generate the report
      const report = await generateReport(
        profile,
        validated.reportType,
        validated.includeCharts
      );

      // Send notification
      await sendNotification( profile.email, report.id );

      return {
        reportId: report.id,
        downloadUrl: report.url,
        generatedAt: new Date().toISOString()
      };
    } catch ( error ) {
      throw new FatalError( `Report generation failed: ${error.message}` );
    }
  }
}

After: Output SDK

// workflow.ts
import { workflow, z } from '@output.ai/core';
import {
  validateInput,
  fetchUserProfile,
  generateReport,
  sendNotification
} from './steps.js';

const ReportInputSchema = z.object( {
  userId: z.string(),
  reportType: z.enum( [ 'daily', 'weekly', 'monthly' ] ),
  includeCharts: z.boolean()
} );

const ReportOutputSchema = z.object( {
  reportId: z.string(),
  downloadUrl: z.string(),
  generatedAt: z.string()
} );

export default workflow( {
  name: 'generateReport',
  description: 'Generate user reports with optional charts',
  inputSchema: ReportInputSchema,
  outputSchema: ReportOutputSchema,
  fn: async ( input ) => {
    // Validate input
    const validated = await validateInput( {
      userId: input.userId,
      reportType: input.reportType,
      includeCharts: input.includeCharts
    } );

    // Fetch user profile
    const profile = await fetchUserProfile( { userId: input.userId } );

    // Generate the report
    const report = await generateReport( {
      profile,
      reportType: validated.reportType,
      includeCharts: validated.includeCharts
    } );

    // Send notification
    await sendNotification( {
      email: profile.email,
      reportId: report.id
    } );

    return {
      reportId: report.id,
      downloadUrl: report.url,
      generatedAt: new Date().toISOString()
    };
  }
} );

Verification Checklist

• Class converted to workflow() function
• Input/Output interfaces converted to Zod schemas
• Workflow name matches legacy name (if needed)
• Steps called with object parameters
• Try-catch blocks removed
• Imports use @output.ai/core
• File imports have .js extension
• export default used

Related Skills

• flow-convert-activities-to-steps - Step conversion
• flow-error-try-catch-removal - Try-catch antipattern
• flow-error-zod-import - Zod import issues
• flow-validation-checklist - Complete validation