zod

Validate and parse unknown runtime inputs into typed values with Zod schemas.

1|Updated Mar 11, 2026
One-click install
npx skills add https://github.com/antonyfmunoz/OS --skill zod-antonyfmunoz
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: zod
Source: https://github.com/antonyfmunoz/OS/tree/main/skills/tools/zod
Command: npx skills add https://github.com/antonyfmunoz/OS --skill zod-antonyfmunoz

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

Zod prevents runtime type drift by turning unknown inputs into well-typed values at trust boundaries, so your code stops guessing and fails fast with structured errors.

Core Features & Use Cases

  • Schema-first parsing: define types once and parse unknown into a concrete, inferred TypeScript type.
  • Trust-boundary validation: validate form inputs, Express request bodies/queries, environment variables at boot, and API/LLM payloads with safeParse at request time.
  • Composable validation: build robust schemas using objects, unions (including discriminated unions), refinements, transforms, coercion, branding, and consistent error formatting via flatten() / format().

Quick Start

Use zod to safely parse an incoming request body with a shared schema: ask the AI to generate a Zod schema and an Express middleware that returns a 400 with error.flatten().fieldErrors on invalid input.

Frequently Asked Questions about zod

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I validate unknown runtime inputs and convert them into inferred TypeScript types?

Schema-first validation parses unknown runtime inputs into concrete TypeScript types at trust boundaries. You define a Zod schema once, and parsing automatically infers the corresponding typed value for your application.

How do I return client-friendly field errors from Express middleware using safeParse?

Express middleware can validate request bodies using safeParse and return a 400 status with error.flatten().fieldErrors. This provides structured, client-friendly validation messages for invalid API inputs.

Does Zod work with React Hook Form for schema-first form validation?

Yes, Zod integrates with React Hook Form to enforce schema-first validation. You define validation rules once in a Zod schema, and the form library applies them to parse and validate user inputs safely.

Can I build composable validators with discriminated unions and transforms in Zod?

Yes, Zod supports composable validation using objects, discriminated unions, refinements, transforms, and coercion. This allows you to build robust schemas for parsing structured JSON from clients or LLM outputs.

What is the best way to validate environment variables at boot in TypeScript?

Schema-first validation checks environment variables at boot by parsing unknown process inputs with a Zod schema. This ensures your application fails fast with structured errors if required environment configurations are missing or invalid.

Why should I use schema-first validation instead of manual type assertions for API payloads?

Schema-first validation prevents runtime type drift by turning unknown API payloads into well-typed values at trust boundaries. Manual type assertions skip validation, leaving your code guessing and vulnerable to malformed structured JSON.