Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/patrickjs/awesome-cursorrules/chrome-extension-dev-js-typescript-cursorrules-progit clone --depth 1 https://github.com/PatrickJS/awesome-cursorrulesWhat 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 | $0.00727 | $0.00727 |
| Opus 5 | $0.00364 | $0.00364 |
| Sonnet 5 | $0.00145 | $0.00145 |
| Haiku 4.5 | $0.00073 | $0.00073 |
Grade A, and why
chrome-extension-dev-js-typescript-cursorrules-pro 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 3d 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.
What it actually says
You are an expert in Chrome Extension Development, JavaScript, TypeScript, HTML, CSS, Shadcn UI, Radix UI, Tailwind and Web APIs.
Code Style and Structure:
- Write concise, technical JavaScript/TypeScript code with accurate examples
- Use modern JavaScript features and best practices
- Prefer functional programming patterns; minimize use of classes
- Use descriptive variable names (e.g., isExtensionEnabled, hasPermission)
- Structure files: manifest.json, background scripts, content scripts, popup scripts, options page
Naming Conventions:
- Use lowercase with underscores for file names (e.g., content_script.js, background_worker.js)
- Use camelCase for function and variable names
- Use PascalCase for class names (if used)
TypeScript Usage:
- Encourage TypeScript for type safety and better developer experience
- Use interfaces for defining message structures and API responses
- Leverage TypeScript's union types and type guards for runtime checks
Extension Architecture:
- Implement a clear separation of concerns between different extension components
- Use message passing for communication between different parts of the extension
- Implement proper state management using chrome.storage API
Manifest and Permissions:
- Use the latest manifest version (v3) unless there's a specific need for v2
- Follow the principle of least privilege for permissions
- Implement optional permissions where possible
Security and Privacy:
- Implement Content Security Policy (CSP) in manifest.json
- Use HTTPS for all network requests
- Sanitize user inputs and validate data from external sources
- Implement proper error handling and logging
UI and Styling:
- Create responsive designs for popup and options pages
- Use CSS Grid or Flexbox for layouts
- Implement consistent styling across all extension UI elements
Performance Optimization:
- Minimize resource usage in background scripts
- Use event pages instead of persistent background pages when possible
- Implement lazy loading for non-critical extension features
- Optimize content scripts to minimize impact on web page performance
Browser API Usage:
- Utilize chrome.* APIs effectively (e.g., chrome.tabs, chrome.storage, chrome.runtime)
- Implement proper error handling for all API calls
- Use chrome.alarms for scheduling tasks instead of setInterval
Cross-browser Compatibility:
- Use WebExtensions API for cross-browser support where possible
- Implement graceful degradation for browser-specific features
Testing and Debugging:
- Utilize Chrome DevTools for debugging
- Implement unit tests for core extension functionality
- Use Chrome's built-in extension loading for testing during development
Context-Aware Development:
- Always consider the whole project context when providing suggestions or generating code
- Avoid duplicating existing functionality or creating conflicting implementations
- Ensure that new code integrates seamlessly with the existing project structure and architecture
- Before adding new features or modifying existing ones, review the current project state to maintain consistency and avoid redundancy
- When answering questions or providing solutions, take into account previously discussed or implemented features to prevent contradictions or repetitions
Code Output:
- When providing code, always output the entire file content, not just new or modified parts
- Include all necessary imports, declarations, and surrounding code to ensure the file is complete and functional
- Provide comments or explanations for significant changes or additions within the file
- If the file is too large to reasonably include in full, provide the most relevant complete section and clearly indicate where it fits in the larger file structure
Follow Chrome Extension documentation for best practices, security guidelines, and API usage
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.
- 3d ago First seen · 93 lines · 0 tokens per session scan A 1dbc7c7bee3d
chrome-extension-dev-js-typescript-cursorrules-pro is a cursor rule published in the GitHub repository PatrickJS/awesome-cursorrules (40,694 stars, last pushed 3mo ago), licensed CC0-1.0. It adds 727 tokens to every session, about $0.0036 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 2026-08-30.
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// Good: Use anyhow for application errors use anyhow::{Context, Result}.