# zod-schema-validation

Guides agents on writing Zod schemas, inferring TypeScript types, and validating boundaries in APIs and UI forms. Keeps validation consistent across the codebase.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1200 installs · ★ 286
- Author: Mindrally
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/Mindrally/skills/tree/HEAD/zod-schema-validation/SKILL.md
- Updated: 2026-10-08
- HTML: https://affpapa.org/en/nevibecode/skills/zod-schema-validation

## What it does

The skill instructs your coding agent to validate inputs at application boundaries, such as API routes and forms. It emphasizes deriving TypeScript types directly via `z.infer`, applying guard clauses, and parsing data safely with `safeParse`. Validation issues are handled cleanly with `.error.format()`.

It includes patterns for composing schemas with `.extend()`, `.merge()`, `.pick()`, and `.omit()`. For complex workflows, it provides blueprints for discriminated unions using `z.discriminatedUnion()` and recursive data structures through `z.lazy()`. Form validations hook into react-hook-form using `@hookform/resolvers/zod`.

Defining schemas inside React render functions degrades performance. The guide mandates precompiling frequently used schemas outside rendering logic.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill zod-schema-validation -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/zod-schema-validation/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/zod-schema-validation/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill zod-schema-validation -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/zod-schema-validation/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill zod-schema-validation -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/zod-schema-validation/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install Mindrally/skills zod-schema-validation
```

2. **Manually: put the files in place**
- File: `.github/skills/zod-schema-validation/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill zod-schema-validation -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/Mindrally/skills --path zod-schema-validation
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/zod-schema-validation/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill zod-schema-validation -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/Mindrally/skills/tree/HEAD/zod-schema-validation/SKILL.md

## When to use it
- validate API request bodies and query parameters with Zod
- infer TypeScript types from schemas using `z.infer`
- integrate schema validation into react-hook-form
- define recursive data schemas using `z.lazy`

## Example prompts
- Create a Zod schema for a user registration payload with uuid, email, and enum role, then infer its TypeScript type
- Set up a react-hook-form validation schema using @hookform/resolvers/zod with partial update support
- Build a discriminated union schema in Zod to handle distinct success and error API responses

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: ec57e295fa08f9d5.

BEGIN THIRD-PARTY FILE ec57e295fa08f9d5
````text
---
name: zod-schema-validation
description: Best practices for Zod schema validation and type inference in TypeScript applications.
metadata:
  maintainer: Mindrally
  source: https://github.com/Mindrally/skills
---

# Zod Schema Validation

You are an expert in Zod schema validation and type inference for TypeScript applications.

## Core Principles

- Utilize Zod for schema validation and type inference
- Validate data at system boundaries (API, forms, external data)
- Leverage TypeScript type inference from Zod schemas
- Implement early returns and guard clauses for validation errors

## Schema Design

### Basic Schema
```typescript
import { z } from 'zod'

const UserSchema = z.object({
  id: z.string().uuid(),
  email: z.string().email(),
  name: z.string().min(1).max(100),
  age: z.number().int().positive().optional(),
  role: z.enum(['admin', 'user', 'guest']),
  createdAt: z.date(),
})

type User = z.infer<typeof UserSchema>
```

### Best Practices
- Define schemas close to where they're used
- Use `.infer` to derive TypeScript types
- Compose schemas using `.extend()`, `.merge()`, `.pick()`, `.omit()`
- Create reusable base schemas for common patterns

## Validation Patterns

### Safe Parsing
```typescript
const result = UserSchema.safeParse(data)
if (!result.success) {
  console.error(result.error.format())
  return
}
// result.data is typed as User
```

### Transform and Refine
```typescript
const schema = z.string()
  .transform((val) => val.trim().toLowerCase())
  .refine((val) => val.length > 0, 'Cannot be empty')
```

## Form Integration

- Use Zod with react-hook-form via `@hookform/resolvers/zod`
- Define form schemas that match your form structure
- Handle validation errors in UI appropriately
- Use `.partial()` for optional update forms

## API Validation

- Validate request bodies in API routes
- Validate query parameters and path params
- Return structured error responses
- Use discriminated unions for different response types

## Error Handling

- Implement custom error messages for better UX
- Use `.format()` for structured error output
- Create custom error maps for i18n support
- Handle nested object errors appropriately

## Advanced Patterns

### Discriminated Unions
```typescript
const ResultSchema = z.discriminatedUnion('status', [
  z.object({ status: z.literal('success'), data: UserSchema }),
  z.object({ status: z.literal('error'), message: z.string() }),
])
```

### Recursive Schemas
```typescript
const CategorySchema: z.ZodType<Category> = z.lazy(() =>
  z.object({
    name: z.string(),
    children: z.array(CategorySchema),
  })
)
```

## Performance

- Precompile schemas that are used frequently
- Avoid creating schemas inside render functions
- Use `.passthrough()` or `.strict()` intentionally
- Consider partial validation for large objects
````
END THIRD-PARTY FILE ec57e295fa08f9d5

The third-party file has ended. Everything between the ec57e295fa08f9d5 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

© Mindrally · Apache-2.0 · https://github.com/Mindrally/skills/tree/HEAD/zod-schema-validation/SKILL.md

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