Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/aj-geddes/useful-ai-promptsnpx agentmods add skills/aj-geddes/useful-ai-prompts/form-validationWrote 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/aj-geddes/useful-ai-prompts/form-validation)<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/form-validation"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/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.
<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/form-validation"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/form-validation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
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 | $0.00034 | $0.00509 |
| Opus 5 | $0.00017 | $0.00254 |
| Sonnet 5 | $0.00007 | $0.00102 |
| Haiku 4.5 | $0.00003 | $0.00051 |
Grade A, and why
form-validation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Form Validation
Table of Contents
Overview
Implement comprehensive form validation including client-side validation, server-side synchronization, and real-time error feedback with TypeScript type safety.
When to Use
- User input validation
- Form submission handling
- Real-time error feedback
- Complex validation rules
- Multi-step forms
Quick Start
Minimal working example:
// types/form.ts
export interface LoginFormData {
email: string;
password: string;
rememberMe: boolean;
}
export interface RegisterFormData {
email: string;
password: string;
confirmPassword: string;
name: string;
terms: boolean;
}
// components/LoginForm.tsx
import { useForm, SubmitHandler } from 'react-hook-form';
import { LoginFormData } from '../types/form';
const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
export const LoginForm: React.FC = () => {
const {
register,
handleSubmit,
// ... (see reference guides for full implementation)
Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| React Hook Form with TypeScript | React Hook Form with TypeScript |
| Formik with Yup Validation | Formik with Yup Validation |
| Vue Vee-Validate | Vue Vee-Validate |
| Custom Validator Hook | Custom Validator Hook |
| Server-Side Validation Integration | Server-Side Validation Integration |
Best Practices
✅ DO
- Follow established patterns and conventions
- Write clean, maintainable code
- Add appropriate documentation
- Test thoroughly before deploying
❌ DON'T
- Skip testing or validation
- Ignore error handling
- Hard-code configuration values
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.
- 9d ago First seen · 90 lines · 34 tokens per session scan A 83e2bc70ce12
form-validation is a skill published in the GitHub repository aj-geddes/useful-ai-prompts (338 stars, last pushed 6mo ago), licensed MIT. It adds 34 tokens to every session and 509 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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