Add Subresource Integrity to external scripts
SkillWeb & browsingSubresource integrity is a skill for AI agents that reviews templates, rendered HTML, or shared components to add integrity hashes to external scripts. It checks the final browser-facing markup, not just the source framework abstraction, so browsers can block tampered code.
Available today. Use it from your connected AI after setup.
No other account needed.
Have an AI agent that can load skills.
Then ask your AI: use the Add Subresource Integrity to external scripts skill
What your AI can do with it
- Add subresource integrity to external scripts on web pages
- Review templates for missing integrity hashes
- Validate rendered HTML rather than only source framework abstractions
- Check shared components for script integrity
- Ensure browsers can block tampered external code
Getting started
- Have an AI agent that can load skills.
- Add the subresource-integrity skill to the agent's available skills.
- Ask the agent to review the templates, rendered HTML, or shared components you want checked.
- Apply the agent's changes so external scripts carry integrity hashes.
What this skill tells your AI
The instructions your AI receives, as published by thedaviddias/front-end-checklist in skills/subresource-integrity/SKILL.md and read by ahel’s review.
When you load JavaScript from a CDN, you're trusting that CDN completely — if it's compromised, attackers can serve malicious JavaScript to all your users. SRI adds a cryptographic hash to the tag; the browser refuses to execute the script if the hash doesn't match the downloaded content, protecting users even if the CDN is compromised or the URL is hijacked.
Quick Reference
- Add integrity="sha384-..." to and tags loading from CDNs
- Always pair integrity with crossorigin="anonymous"
- Generate hashes with openssl or online tools — CDN providers usually supply them
- SRI blocks execution if the file hash doesn't match, preventing CDN compromise attacks
Check
Find all external and tags in this HTML that load from CDNs and don't have integrity attributes. List each one.
Fix
Add appropriate integrity and crossorigin attributes to external CDN resources. Generate the SHA-384 hashes for each resource.
Explain
Explain Subresource Integrity, how it protects against CDN compromise, how to generate SRI hashes, and its limitations.
Code Review
Review templates, server-rendered HTML, and shared components that output markup related to Add Subresource Integrity to external scripts. Flag exact elements, attributes, and routes where the rendered HTML violates the rule.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/html/subresource-integrity
Signals
- GitHub stars
- 74k
- Forks
- 7k
- Last commit
- Aug 2026
Questions
- Why validate the final browser-facing markup instead of the source?
- Because frameworks can transform or inject scripts during rendering. Checking the final markup catches external scripts that source-level review would miss.
- What does an integrity hash do?
- It lets the browser verify that an external script has not been tampered with, and block the script if it fails the check.
- When should this skill be used?
- When reviewing templates, rendered HTML, or shared components that involve external scripts needing subresource integrity.
Advanced
- Item type
- skill
- Key
subresource-integrity- Source
- github.com/thedaviddias/front-end-checklist