Review a website’s Content Security Policy, which controls allowed resources, and identify unsafe HTML insertion. Guide policy changes and sanitization, then verify actual HTTP responses and browser behavior in a production-like environment.
Use when reviewing headers, forms, cookies, or third-party integrations related to Implement a content security policy. Validate the effective browser and HTTP behavior in a production-like environment.
content-security-policy reviews a website’s Content Security Policy (CSP) and helps correct it. CSP limits which resources may load or execute. The review covers HTTP headers and HTML insertion through operations such as innerHTML and dangerouslySetInnerHTML. It addresses restricting allowed sources, using nonces or hashes for inline scripts, and sanitizing HTML to remove unsafe content.
Use it when reviewing settings after integrating an external service, or when organizing the conditions under which scripts can run on an existing site. It also supports introducing CSP gradually while reviewing violation reports. The work covers both resource restrictions and the handling of HTML inserted into a page.
CSP does not replace output encoding or sanitization. Begin with Content-Security-Policy-Report-Only to assess the effects before enforcement. Verify the actual HTTP responses and browser behavior in an environment similar to production.
This overview was written by AI (OpenAI Codex) from the public SKILL.md. Check the original below for the exact behavior.
AI rated this skill on four points using only the contents of its SKILL.md. Stars and popularity are not taken into account.
The total counts each point as A = 25, B = 15, C = 5. Rated by AI (OpenAI Codex) as of Oct 23, 2026. Treat it as a guide and read the original before installing.
Review the instructions the agent will receive before you install.
Content Security Policy prevents cross-site scripting (XSS), clickjacking, and data injection attacks by controlling which resources can be loaded and executed on your pages. It reduces blast radius, but it does not replace output encoding and sanitization.
Check if this website implements a Content Security Policy header and analyze its directives. Also review any use of innerHTML, dangerouslySetInnerHTML, HTML template injection, and Trusted Types enforcement for large applications.
Implement a strict Content Security Policy to prevent XSS attacks and control resource loading. Sanitize untrusted HTML before rendering and add Trusted Types enforcement where the application has enough DOM injection surface to benefit from it.
Explain how CSP provides a security layer that helps detect and mitigate XSS and data injection attacks, and why sanitization is still required before rendering untrusted HTML.
Review server config, headers, forms, and integration points related to Implement a content security policy. Flag exact responses, cookies, or browser behaviors that violate the rule, and verify them against the effective production-like response. Inspect HTML injection sinks and note whether Trusted Types or sanitization protects them.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/security/content-security-policy
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