output-dev-types-file

Creating types.ts Files with Zod Schemas

Overview

This skill documents how to create types.ts files for Output SDK workflows. These files contain Zod schemas for input/output validation and their corresponding TypeScript types.

When to Use This Skill

• Creating a new workflow's type definitions
• Adding new schemas for steps
• Fixing schema validation errors
• Refactoring existing type definitions

Critical Import Rule

ALWAYS import z from @outputai/core, NEVER from zod directly:

// CORRECT
import { z } from '@outputai/core';

// WRONG - will cause runtime errors
import { z } from 'zod';

Related Skill: output-error-zod-import for troubleshooting import issues

Basic Structure

import { z } from '@outputai/core';

// 1. Workflow Input Schema
export const WorkflowInputSchema = z.object( {
  // Define input fields
} );

// 2. Workflow Output Type
export type WorkflowInput = z.infer<typeof WorkflowInputSchema>;
export type WorkflowOutput = /* output type */;

// 3. Step Schemas (for each step)
export const StepNameInputSchema = z.object( {
  // Step input fields
} );

export const StepNameOutputSchema = z.object( {
  // Step output fields
} );

// 4. Type Exports
export type StepNameInput = z.infer<typeof StepNameInputSchema>;
export type StepNameOutput = z.infer<typeof StepNameOutputSchema>;

CRITICAL: Schema Constraints for LLM Output

Schemas passed to aiSdk.Output.object() are sent to LLM providers as tool definitions. Anthropic rejects several JSON Schema constraints that Zod methods produce. Getting this wrong causes runtime errors.

What Is NOT Allowed in LLM Output Schemas

• Numbers: .min(), .max() on z.number() produce minimum/maximum -- rejected by Anthropic.
• Arrays: .min(), .max(), .length() on z.array() produce minItems/maxItems -- Anthropic only supports minItems of 0 or 1. Values like .length( 3 ) or .min( 2 ) will be rejected.