Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/manhvann/codexkitnpx agentmods add skills/manhvann/codexkit/frontend-developmentWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/manhvann/codexkit/frontend-development)<a href="https://agentmods.dev/skills/manhvann/codexkit/frontend-development"><img src="https://agentmods.dev/badge/skills/manhvann/codexkit/frontend-development/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/manhvann/codexkit/frontend-development"><img src="https://agentmods.dev/badge/skills/manhvann/codexkit/frontend-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What 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 5.1 | $0.00044 | $0.02723 |
| Opus 5.5 | $0.00018 | $0.01089 |
| Sonnet 5.5 | $0.00009 | $0.00545 |
| Haiku 4.5 | $0.00004 | $0.00272 |
Grade A, and why
ck:frontend-development 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 1mo 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.
This is a copy
92% identical to frontend-dev-guidelines — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 401 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend Development Guidelines
Purpose
Comprehensive guide for modern React development, emphasizing Suspense-based data fetching, lazy loading, proper file organization, and performance optimization.
When to Use This Skill
- Creating new components or pages
- Building new features
- Fetching data with TanStack Query
- Setting up routing with TanStack Router
- Styling components with MUI v7
- Performance optimization
- Organizing frontend code
- TypeScript best practices
Quick Start
New Component Checklist
Creating a component? Follow this checklist:
- Use
React.FC<Props>pattern with TypeScript - Lazy load if heavy component:
React.lazy(() => import()) - Wrap in
<SuspenseLoader>for loading states - Use
useSuspenseQueryfor data fetching - Import aliases:
@/,~types,~components,~features - Styles: Inline if <100 lines, separate file if >100 lines
- Use
useCallbackfor event handlers passed to children - Default export at bottom
- No early returns with loading spinners
- Use
useMuiSnackbarfor user notifications
New Feature Checklist
Creating a feature? Set up this structure:
- Create
features/{feature-name}/directory - Create subdirectories:
api/,components/,hooks/,helpers/,types/ - Create API service file:
api/{feature}Api.ts - Set up TypeScript types in
types/ - Create route in
routes/{feature-name}/index.tsx - Lazy load feature components
- Use Suspense boundaries
- Export public API from feature
index.ts
Import Aliases Quick Reference
| Alias | Resolves To | Example |
|---|---|---|
@/ |
src/ |
import { apiClient } from '@/lib/apiClient' |
~types |
src/types |
import type { User } from '~types/user' |
~components |
src/components |
import { SuspenseLoader } from '~components/SuspenseLoader' |
~features |
src/features |
import { authApi } from '~features/auth' |
What ships with it
10 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- resources/common-patterns.md 8.2 KB
- resources/complete-examples.md 24 KB
- resources/component-patterns.md 11 KB
- resources/data-fetching.md 19 KB
- resources/file-organization.md 12 KB
- resources/loading-and-error-states.md 12 KB
- resources/performance.md 9.4 KB
- resources/routing-guide.md 7.0 KB
- resources/styling-guide.md 7.7 KB
- resources/typescript-standards.md 8.2 KB
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.
- 1mo ago First seen · 401 lines · 44 tokens per session scan A d2ecde80ed80
ck:frontend-development is a skill published in the GitHub repository manhvann/codexkit (89 stars, last pushed 1mo ago), licensed MIT. It adds 44 tokens to every session and 2,723 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 92% identical to frontend-dev-guidelines, differing in 8 lines, and is treated as a copy.
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