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/rm2thaddeus/pixel_detective/frontend-development-indexgit clone --depth 1 https://github.com/rm2thaddeus/Pixel_DetectiveWhat 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 | $0.00000 | $0.02444 |
| Opus 5 | $0.00000 | $0.01222 |
| Sonnet 5 | $0.00000 | $0.00489 |
| Haiku 4.5 | $0.00000 | $0.00244 |
Grade A, and why
frontend-development-index 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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 329 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend Development Master Index
🎯 COMPLETE FRONTEND DEVELOPMENT GUIDE
This index provides comprehensive guidance for frontend development based on proven patterns from Sprint 10 experiences and architectural lessons learned.
📋 RULE SELECTION GUIDE - Choose Your Path:
🚀 New Component Development
START HERE: component-architecture-patterns.mdc
- Component composition patterns and anti-patterns
- Breaking down "God Components" (424+ line components)
- Custom hooks for logic extraction
- Container/Presentational patterns
- Testing strategies for components
💧 Hydration Issues (CRITICAL)
START HERE: nextjs-hydration-prevention.mdc
- Two-stage rendering patterns for SSR/CSR compatibility
- ColorModeScript placement in document
<head> - Mounted state patterns for client-only components
- Forbidden browser API usage in render phase
- Emergency hydration debugging protocols
🔄 API Integration & State Management
START HERE: react-query-api-integration.mdc
- Mandatory React Query for all server state
- Query/mutation patterns with error handling
- Background polling and cache management
- API client setup with interceptors
- Query key conventions and invalidation
🎨 User Experience & Workflows
START HERE: ux-workflow-patterns.mdc
- Critical UX flaw fixes (file upload workflows)
- Real-time feedback patterns
- Progressive setup flows
- Error recovery patterns
- Mobile-first responsive design
⚡ Performance Optimization
START HERE: nextjs-performance-optimization.mdc
- Next.js Image component optimization
- Bundle analysis and code splitting
- Memory leak prevention
- Performance monitoring
- Core Web Vitals optimization
🔥 SPRINT 10 CRITICAL LESSONS INTEGRATION
The Big 5 Frontend Issues (From Sprint 10):
- Hydration Errors →
nextjs-hydration-prevention.mdc- Server/client HTML mismatch in dark mode
- ColorModeScript placement issues
- Client-only component patterns
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.
- 2d ago First seen · 329 lines · 0 tokens per session scan A ecda6d33ed69
frontend-development-index is a cursor rule published in the GitHub repository rm2thaddeus/Pixel_Detective (21 stars, last pushed 7mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 2,444 tokens. 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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