form-validation

form-validation is a skill for Claude Code from SebastianLuser/claude-code-arcane. It costs 33 tokens per session (887 once invoked), scanned A, original, no licence file.

A guide to validating web forms with React Hook Form and Zod, including client-side and server-side checks, schema design, and error messages. It also covers Latin American form fields.

In plain words
What is it for?
Use it when designing or reviewing form schemas, deciding where checks should run, or improving how validation errors are shown.
Why use it?
It helps prevent inconsistent validation, confusing errors, and unsafe reliance on browser-side checks alone.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it when designing or reviewing form schemas, deciding where checks should run, or improving how validation errors are shown.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sebastianluser/claude-code-arcane/form-validation
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 SebastianLuser/claude-code-arcane --skill form-validation
Clone the repo
git clone --depth 1 https://github.com/SebastianLuser/claude-code-arcane

Made for: Claude Code.

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 form-validation

README.md
[![agentmods](https://agentmods.dev/badge/skills/sebastianluser/claude-code-arcane/form-validation/github.svg)](https://agentmods.dev/skills/sebastianluser/claude-code-arcane/form-validation)
Your own site
<a href="https://agentmods.dev/skills/sebastianluser/claude-code-arcane/form-validation"><img src="https://agentmods.dev/badge/skills/sebastianluser/claude-code-arcane/form-validation/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 form-validation

Your own site · 80×15
<a href="https://agentmods.dev/skills/sebastianluser/claude-code-arcane/form-validation"><img src="https://agentmods.dev/badge/skills/sebastianluser/claude-code-arcane/form-validation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 887 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 unknown 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 $0.00033 $0.00887
Opus 5 $0.00016 $0.00443
Sonnet 5 $0.00007 $0.00177
Haiku 4.5 $0.00003 $0.00089

Measured 7d ago against content hash 246520b8043e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

form-validation 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/form-validation/SKILL.md · 76 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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 · 76 lines · 33 tokens per session scan A 246520b8043e

Subscribe to this mod's changes

form-validation is a skill published in the GitHub repository SebastianLuser/claude-code-arcane (2 stars, last pushed yesterday), with no licence file. It adds 33 tokens to every session and 887 once invoked, about $0.0002 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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