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.
npx skills add fellipeutaka/leon --skill zodgit clone --depth 1 https://github.com/fellipeutaka/leonWrote 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.
[](https://agentmods.dev/skills/fellipeutaka/leon/zod)<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.
<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>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00185 | $0.03162 |
| Opus 5.5 | $0.00074 | $0.01265 |
| Sonnet 5.5 | $0.00037 | $0.00632 |
| Haiku 4.5 | $0.00018 | $0.00316 |
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 2mo 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.
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)
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.
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.
- 2mo ago First seen · 404 lines · 185 tokens per session scan A 7e4fef6e008a
zod is a skill published in the GitHub repository fellipeutaka/leon (5 stars, last pushed 6d ago), licensed MIT. It adds 185 tokens to every session and 3,162 once invoked, about $0.0007 per session on Opus 5.5. 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.
zod compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| zodfellipeutaka/leon | Skill | 5 | 6d ago | MIT | A | 185 | Claude Code, Codex |
| stripe-projectse2b-dev/E2B | Skill | 15k | today | Apache-2.0 | A | 51 | Claude Code, Codex |
| nestjs-expertJeffallan/claude-skills | Skill | 12k | yesterday | MIT | A | 107 | Claude Code |
| chat-sdkvercel-labs/open-agents | Skill | 5.9k | 2mo ago | MIT | A | 191 | Claude Code, Codex |
| nestjsericrisco/rsc-harness | Skill | 598 | today | MIT | A | 81 | Claude Code, Codex |
| azure-web-pubsub-tsbenjaminasterA/antigravity-awesome-skills | Skill | 479 | today | MIT | A | 51 | Claude Code, Codex |
| better-authsecondsky/claude-skills | Skill | 248 | 12d ago | MIT | A | 53 | Claude Code |