agentmods.dev

zod

A set of guidelines for using Zod 4, a TypeScript library that checks whether data matches a defined shape. It covers schemas, parsing, inferred types, and validation errors.

In plain words
What is it for?
Use it when creating or reviewing Zod schemas, choosing between parse and safeParse, composing validations, handling errors, or connecting Zod to forms.
Why use it?
It helps prevent inconsistent input checks and makes validation failures and TypeScript types easier to handle correctly.

Skill for Claude CodeCodex

3 13d ago A scan 59 tokens copy · 92% MIT
View the source file PyModel/react-frontend-skills
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/pymodel/react-frontend-skills/zod
Any agent
npx skills add PyModel/react-frontend-skills --skill zod
Clone the repo
git clone --depth 1 https://github.com/PyModel/react-frontend-skills

Made for: Claude Code, Codex.

Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,327 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 92% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00059 $0.01327
Opus 5 $0.00030 $0.00664
Sonnet 5 $0.00012 $0.00265
Haiku 4.5 $0.00006 $0.00133

Measured 3d ago against content hash 0917c5406b53, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

zod scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

92% identical to zod — 10 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/zod/SKILL.md · 126 lines

How it starts

The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Zod Best Practices

Comprehensive schema validation guide for Zod 4 in TypeScript applications. Contains 43 rules across 8 categories, prioritized by impact to guide automated refactoring and code generation.

When to Apply

Reference these guidelines when:

  • Writing new Zod schemas
  • Choosing between parse() and safeParse()
  • Implementing type inference with z.infer
  • Handling validation errors for user feedback
  • Composing complex object schemas
  • Using refinements and transforms
  • Optimizing bundle size and validation performance
  • Reviewing Zod code for best practices

Rule Categories by Priority

Priority Category Impact Prefix
1 Schema Definition CRITICAL schema-
2 Parsing & Validation CRITICAL parse-
3 Type Inference HIGH type-
4 Error Handling HIGH error-
5 Object Schemas MEDIUM-HIGH object-
6 Schema Composition MEDIUM compose-
7 Refinements & Transforms MEDIUM refine-
8 Performance & Bundle LOW-MEDIUM perf-

Quick Reference

1. Schema Definition (CRITICAL)

  • schema-use-primitives-correctly - Use correct primitive schemas for each type
  • schema-use-unknown-not-any - Use z.unknown() instead of z.any() for type safety
  • schema-avoid-optional-abuse - Avoid overusing optional fields
  • schema-string-validations - Apply string validations at schema definition
  • schema-use-enums - Use enums for fixed string values
  • schema-coercion-for-form-data - Use coercion for form and query data

2. Parsing & Validation (CRITICAL)

  • parse-use-safeparse - Use safeParse() for user input
  • parse-async-for-async-refinements - Use parseAsync for async refinements
  • parse-handle-all-issues - Handle all validation issues not just first
  • parse-validate-early - Validate at system boundaries
  • parse-avoid-double-validation - Avoid validating same data twice
  • parse-never-trust-json - Never trust JSON.parse output

Read the full file on GitHub · 126 lines

Files

What ships with it

46 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 126 lines · 59 tokens per session scan A 0917c5406b53

Subscribe to this mod's changes

zod is a skill published in the GitHub repository PyModel/react-frontend-skills (3 stars, last pushed 13d ago), licensed MIT. It adds 59 tokens to every session and 1,327 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to zod, differing in 10 lines, and is treated as a copy.

LanguagesTypeScriptagent-skillsai-agentsai-coding-assistantclaude-codecodexcursor
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