Agent skill · security · secondsky
security-headers-configuration
Configures HTTP security headers to protect against XSS, clickjacking, and MIME sniffing attacks. Use when hardening web applications, passing security audits, or implementing Content Security Policy.
Why this skill is useful
Provides specific implementation details for configuring security headers in web applications, which the AI may not generate accurately on its own.
What it needs
Requires helmet installed locally. About 1k tokens when loaded. Last updated 2026-08-06. 204 stars on the source repository.
What this skill does
Security Headers Configuration Implement HTTP security headers to defend against common browser-based attacks. Essential Headers Header Purpose Value -------- --------- ------- HSTS Force HTTPS max-age=31536000; includeSubDomains CSP Restrict resources default-src 'self' X-Frame-Options Prevent clickjacking DENY X-Content-Type-Options Prevent MIME sniffing nosniff Express Implementation Nginx Configuration Verification Tools Security Headers Mozilla Observatory CSP Evaluator Security Headers Checklist [ ] HSTS enabled with long max-age [ ] CSP configured and tested [ ] X-Frame-Options set to DENY [ ] X-Content-Type-Options set to nosniff [ ] Referrer-Policy configured [ ] Permissions-Policy disables unused features Additional Implementations See references/python-apache.md for: Python Flask security headers middleware Flask-Talisman library configuration Apache .htaccess configuration Header testing script Common Mistakes Setting CSP to report-only permanently Using overly permissive policies Forgetting to test after changes Not including all subdomains in HSTS
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills secondsky/security-headers-configuration