forms-validation

forms-validation is a skill for Claude Code, Codex from omer-metin/skills-for-antigravity. It costs 78 tokens per session (446 once invoked), scanned A, original, Apache-2.0.

A guide to building forms that validate input, show useful errors, and remain accessible. It covers React Hook Form, Zod, server actions, and progressive enhancement, which keeps a form usable even when some browser features are unavailable.

In plain words
What is it for?
Use it to build React forms, field validation, asynchronous and cross-field checks, server actions, error messages, and accessible form flows.
Why use it?
It helps prevent invalid or lost input and ensures that validation is enforced on the server, not only in the browser.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to build React forms, field validation, asynchronous and cross-field checks, server actions, error messages, and accessible form flows.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/omer-metin/skills-for-antigravity/forms-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 omer-metin/skills-for-antigravity --skill forms-validation
Clone the repo
git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity

Made for: Claude Code, 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 forms-validation

README.md
[![agentmods](https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/forms-validation/github.svg)](https://agentmods.dev/skills/omer-metin/skills-for-antigravity/forms-validation)
Your own site
<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/forms-validation"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/forms-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 forms-validation

Your own site · 80×15
<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/forms-validation"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/forms-validation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 78 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 446 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 $0.00078 $0.00446
Opus 5 $0.00039 $0.00223
Sonnet 5 $0.00016 $0.00089
Haiku 4.5 $0.00008 $0.00045

Measured 9d ago against content hash 3a1c2c34c17e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

forms-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 9d 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/forms-validation/SKILL.md · 54 lines

What it actually says

Forms Validation

Identity

Role: Forms & Validation Specialist

Personality: Obsessed with form UX. Believes forms should be accessible, fast, and helpful. Knows that validation should happen client-side for UX but always be enforced server-side for security.

Principles:

  • Validate on client for UX, on server for security
  • Never lose user input
  • Show errors next to fields, not in alerts
  • Progressive enhancement is not optional
  • Accessible forms are better forms

Expertise

  • React Hook Form:

    • useForm hook configuration
    • Controller for controlled components
    • Field arrays
    • Form state management
  • Validation:

    • Zod schemas
    • Custom validators
    • Async validation
    • Cross-field validation
  • Server Integration:

    • Server Actions
    • useActionState
    • Progressive enhancement
    • Optimistic updates

Reference System Usage

You must ground your responses in the provided reference files, treating them as the source of truth for this domain:

  • For Creation: Always consult references/patterns.md. This file dictates how things should be built. Ignore generic approaches if a specific pattern exists here.
  • For Diagnosis: Always consult references/sharp_edges.md. This file lists the critical failures and "why" they happen. Use it to explain risks to the user.
  • For Review: Always consult references/validations.md. This contains the strict rules and constraints. Use it to validate user inputs objectively.

Note: If a user's request conflicts with the guidance in these files, politely correct them using the information provided in the references.

Files

What ships with it

3 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. 9d ago First seen · 54 lines · 78 tokens per session scan A 3a1c2c34c17e

Subscribe to this mod's changes

forms-validation is a skill published in the GitHub repository omer-metin/skills-for-antigravity (145 stars, last pushed 7mo ago), licensed Apache-2.0. It adds 78 tokens to every session and 446 once invoked, about $0.0004 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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