How do I install the Form Captcha skill?

Run npx skillmds@latest add thedaviddias/form-captcha in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Form Captcha safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Form Captcha?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Form Captcha free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Form Captcha?

thedaviddias (@thedaviddias) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Form Captcha by thedaviddias — Agent Skill

Name: Form Captcha
Author: thedaviddias

File contents

Protect public forms with CAPTCHA

An unprotected registration form can create thousands of spam accounts per minute; an unprotected login form enables credential stuffing attacks that test millions of username/password combinations from data breaches.

Quick Reference

Public forms (contact, registration, login, password reset, comment) without CAPTCHA are targets for automated abuse
Prefer invisible/automated solutions (Cloudflare Turnstile, Google reCAPTCHA v3, hCaptcha) over interactive challenges that harm UX
Always validate CAPTCHA tokens server-side — client-side validation is bypassable
Rate limiting is complementary to CAPTCHA but not a substitute — bots can solve rate limits with distributed attacks
Honeypot fields (hidden inputs that users never fill but bots do) are a lightweight CAPTCHA alternative for low-risk forms

Check

Identify all public-facing forms (contact, registration, login, password reset, newsletter, comment). Check whether each has CAPTCHA, honeypot fields, or server-side rate limiting. Verify any CAPTCHA tokens are validated server-side.

Fix

Integrate a CAPTCHA service (Cloudflare Turnstile, hCaptcha, or Google reCAPTCHA v3) on all public forms. Validate the CAPTCHA response token on your server before processing the form submission. Add rate limiting as a defense-in-depth measure.

Explain

Explain what credential stuffing and spam bot attacks are, how CAPTCHA protects public forms, the trade-offs between different CAPTCHA approaches (v2 checkbox, v3 invisible, Turnstile), and why server-side validation is required.

Code Review

Review server config, headers, forms, and integration points related to Protect public forms with CAPTCHA. Flag exact responses, cookies, or browser behaviors that violate the rule, and verify them against the effective production-like response.

For full implementation details, code examples, and framework-specific guidance, see references/rule.md.

Rule page: https://frontendchecklist.io/en/rules/security/form-captcha

---name: form-captchadescription: Use when reviewing public HTML forms (no authentication required to reach them) for bot and abuse protection mechanisms.---# Protect public forms with CAPTCHAAn unprotected registration form can create thousands of spam accounts per minute; an unprotected login form enables credential stuffing attacks that test millions of username/password combinations from data breaches.## Quick Reference- Public forms (contact, registration, login, password reset, comment) without CAPTCHA are targets for automated abuse- Prefer invisible/automated solutions (Cloudflare Turnstile, Google reCAPTCHA v3, hCaptcha) over interactive challenges that harm UX- Always validate CAPTCHA tokens server-side — client-side validation is bypassable- Rate limiting is complementary to CAPTCHA but not a substitute — bots can solve rate limits with distributed attacks- Honeypot fields (hidden inputs that users never fill but bots do) are a lightweight CAPTCHA alternative for low-risk forms## CheckIdentify all public-facing forms (contact, registration, login, password reset, newsletter, comment). Check whether each has CAPTCHA, honeypot fields, or server-side rate limiting. Verify any CAPTCHA tokens are validated server-side.## FixIntegrate a CAPTCHA service (Cloudflare Turnstile, hCaptcha, or Google reCAPTCHA v3) on all public forms. Validate the CAPTCHA response token on your server before processing the form submission. Add rate limiting as a defense-in-depth measure.## ExplainExplain what credential stuffing and spam bot attacks are, how CAPTCHA protects public forms, the trade-offs between different CAPTCHA approaches (v2 checkbox, v3 invisible, Turnstile), and why server-side validation is required.## Code ReviewReview server config, headers, forms, and integration points related to Protect public forms with CAPTCHA. Flag exact responses, cookies, or browser behaviors that violate the rule, and verify them against the effective production-like response.---For full implementation details, code examples, and framework-specific guidance,see `references/rule.md`.Rule page: https://frontendchecklist.io/en/rules/security/form-captcha

Frequently asked questions

Form Captcha