# zod-validation-utilities

Guides Zod v4 validation for TypeScript APIs, forms, and configuration. Use it when external input needs parsing, coercion, and clear validation errors.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 3800 installs · ★ 363
- Author: giuseppe-trisciuoglio
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/giuseppe-trisciuoglio/developer-kit/tree/HEAD/plugins/developer-kit-typescript/skills/zod-validation-utilities/SKILL.md
- Updated: 2026-09-10
- HTML: https://affpapa.org/en/nevibecode/skills/zod-validation-utilities

## What it does

This skill lays out reusable Zod v4 patterns for primitives, object schemas, arrays, tuples, and discriminated unions. It places validation at application boundaries such as HTTP handlers, queues, and configuration loaders.

It uses `z.coerce.*` when incoming types are uncertain, while `transform`, `refine`, and `superRefine` keep data changes and cross-field checks near the schema. A `safeParse` flow branches on `result.success`, then returns formatted errors or typed `result.data`. Schemas can export matching `z.input` and `z.output` types.

The material also covers React Hook Form through `zodResolver`. Check the installed Zod major version first: the shown APIs target v4, so copying them into an older dependency is a risk.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill zod-validation-utilities -a claude-code
```

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

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill zod-validation-utilities -a codex
```

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

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill zod-validation-utilities -a cursor
```

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

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install giuseppe-trisciuoglio/developer-kit zod-validation-utilities
```

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

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill zod-validation-utilities -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/giuseppe-trisciuoglio/developer-kit --path plugins/developer-kit-typescript/skills/zod-validation-utilities
```

### Windsurf (Devin Desktop)

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

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill zod-validation-utilities -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/giuseppe-trisciuoglio/developer-kit/tree/HEAD/plugins/developer-kit-typescript/skills/zod-validation-utilities/SKILL.md

## When to use it
- validate an API request body against a schema
- coerce query strings into numbers and dates
- format validation failures from `safeParse`
- compare related password fields with `superRefine`
- connect a Zod schema to React Hook Form

## Example prompts
- "Create a Zod v4 schema for this API request body and handle errors with `safeParse`."
- "Add `z.coerce.*` for pagination parameters and export `z.input` and `z.output`."
- "Wire this schema into a React Hook Form form using `zodResolver`."

## Source text · SKILL.md · MIT

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: d40bb2d4525c7849.

BEGIN THIRD-PARTY FILE d40bb2d4525c7849
````text
---
name: zod-validation-utilities
description: Creates reusable Zod v4 schemas, validates API payloads, forms, and configuration input, transforms and coerces data safely, and handles validation errors with strong type inference for TypeScript applications. Use when designing validation layers, parsing `z.string()`, `z.object()`, or `z.email()` schemas, or implementing runtime type-safe data validation.
allowed-tools: Read, Write, Edit, Bash, Grep, Glob
---

# Zod Validation Utilities

## Overview

Production-ready Zod v4 patterns for reusable, type-safe validation with minimal boilerplate. Focuses on modern APIs, predictable error handling, and form integration.

## When to Use

- Defining request/response validation schemas in TypeScript services
- Parsing untrusted input from APIs, forms, env vars, or external systems
- Standardizing coercion, transforms, and cross-field validation
- Building reusable schema utilities across teams
- Integrating React Hook Form with Zod using `zodResolver`

## Instructions

1. Start with strict object schemas and explicit field constraints
2. Prefer modern Zod v4 APIs and the `error` option for error messages
3. Use coercion at boundaries (`z.coerce.*`) when input types are uncertain
4. Keep business invariants in `refine`/`superRefine` close to schema definitions
5. Export both schema and inferred types (`z.input`/`z.output`) for consistency
6. Reuse utility schemas (email, id, dates, pagination) to reduce duplication

## Validation Workflow

When integrating validation into an API handler or service:

1. **Define** the schema at the boundary (handler, queue, config loader)
2. **Parse** with `safeParse` to handle errors gracefully
3. **Check** `result.success` to branch on failure/success
4. **Use** `result.data` with full type inference in success path
5. **Return** formatted errors or proceed with validated data

See example 7 (`safeParse` workflow) for the complete pattern.

## Examples

### 1) Modern Zod 4 primitives and object errors

```ts
import { z } from "zod";

export const UserIdSchema = z.uuid({ error: "Invalid user id" });
export const EmailSchema = z.email({ error: "Invalid email" });
export const WebsiteSchema = z.url({ error: "Invalid URL" });

export const UserProfileSchema = z.object(
  {
    id: UserIdSchema,
    email: EmailSchema,
    website: WebsiteSchema.optional(),
  },
  { error: "Invalid user profile payload" }
);
```

### 2) Coercion, preprocess, and transform

```ts
import { z } from "zod";

export const PaginationQuerySchema = z.object({
  page: z.coerce.number().int().min(1).default(1),
````
END THIRD-PARTY FILE d40bb2d4525c7849

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---
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