zod

zod is a skill for Codex from fellipeutaka/leon. It costs 185 tokens per session (3,162 once invoked), scanned A, original, MIT.

A TypeScript library for checking that data matches declared rules, called schemas, and for deriving TypeScript types from those rules.

In plain words
What is it for?
Use it to validate form values, API request and response data, configuration, and other structured input.
Why use it?
It catches invalid input at runtime while keeping the types used by the code aligned with the validation rules.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Use it to validate form values, API request and response data, configuration, and other structured input.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fellipeutaka/leon/zod
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.

Any agent
npx skills add fellipeutaka/leon --skill zod
Clone the repo
git clone --depth 1 https://github.com/fellipeutaka/leon

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for zod

README.md
[![agentmods](https://agentmods.dev/badge/skills/fellipeutaka/leon/zod/github.svg)](https://agentmods.dev/skills/fellipeutaka/leon/zod)
Your own site
<a href="https://agentmods.dev/skills/fellipeutaka/leon/zod"><img src="https://agentmods.dev/badge/skills/fellipeutaka/leon/zod/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for zod

Your own site · 80×15
<a href="https://agentmods.dev/skills/fellipeutaka/leon/zod"><img src="https://agentmods.dev/badge/skills/fellipeutaka/leon/zod.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 185 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,162 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found 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 5.1 $0.00185 $0.03162
Opus 5 $0.00093 $0.01581
Sonnet 5 $0.00037 $0.00632
Haiku 4.5 $0.00018 $0.00316

Measured 7d ago against content hash 7e4fef6e008a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, 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 7d 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.

skills/zod/SKILL.md · 404 lines

How it starts

The opening of the file, as written. The whole thing — 404 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Zod 4

TypeScript-first schema validation. 2kb core bundle (gzipped). Zero dependencies.

CRITICAL: Zod 4 is the current stable version (zod@^4.0.0). Always write Zod 4 code. Never use deprecated Zod 3 patterns.

Import

import * as z from "zod";

For tree-shakable variant (smaller bundles):

import * as z from "zod/mini";

Core Patterns

Parsing

schema.parse(data);           // throws ZodError on failure
schema.safeParse(data);       // returns { success, data?, error? }
await schema.parseAsync(data);
await schema.safeParseAsync(data);

Type Inference

type MyType = z.infer<typeof mySchema>;    // output type
type MyInput = z.input<typeof mySchema>;   // input type
type MyOutput = z.output<typeof mySchema>; // same as z.infer

Primitives

z.string();
z.number();      // finite numbers only (no Infinity, no NaN)
z.bigint();
z.boolean();
z.symbol();
z.undefined();
z.null();
z.date();
z.nan();

Coercion

z.coerce.string();    // String(input)
z.coerce.number();    // Number(input)
z.coerce.boolean();   // Boolean(input)
z.coerce.bigint();    // BigInt(input)
z.coerce.date();      // new Date(input)

String Formats (Top-Level)

Use top-level functions, NOT methods. Methods like z.string().email() are deprecated.

// CORRECT (Zod 4)
z.email();
z.uuid();
z.url();
z.httpUrl();
z.hostname();
z.emoji();
z.base64();
z.base64url();
z.hex();
z.jwt();
z.nanoid();
z.cuid();
z.cuid2();
z.ulid();
z.ipv4();
z.ipv6();
z.mac();
z.cidrv4();
z.cidrv6();
z.hash("sha256");     // "sha1" | "sha384" | "sha512" | "md5"
z.e164();              // phone numbers
z.iso.date();
z.iso.time();
z.iso.datetime();
z.iso.duration();

// DEPRECATED (Zod 3 style — do NOT use)
z.string().email();    // ❌
z.string().uuid();     // ❌
z.string().url();      // ❌

UUID versions

z.uuid();                    // any RFC 9562/4122 UUID
z.uuid({ version: "v4" });  // specific version
z.uuidv4();                  // convenience
z.uuidv6();
z.uuidv7();
z.guid();                    // any 8-4-4-4-12 hex pattern (less strict)

Read the full file on GitHub · 404 lines

Files

What ships with it

6 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. 7d ago First seen · 404 lines · 185 tokens per session scan A 7e4fef6e008a

Subscribe to this mod's changes

zod is a skill published in the GitHub repository fellipeutaka/leon (5 stars, last pushed 7d ago), licensed MIT. It adds 185 tokens to every session and 3,162 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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