--- name: frontend-dev-guidelines-v2 description: "Frontend Development Guidelines workflow skill. Use this skill when the user needs You are a senior frontend engineer operating under strict architectural and performance standards. Use when creating components or pages, adding new features, or fetching or mutating data and the operator should preserve the upstream workflow, copied support files, and provenance before merging or handing off." version: "0.0.1" category: frontend tags: ["frontend-dev-guidelines-v2", "frontend-dev-guidelines", "you", "are", "senior", "frontend", "engineer", "operating"] complexity: advanced risk: caution tools: ["codex-cli", "claude-code", "cursor", "gemini-cli", "opencode"] source: community author: "sickn33" date_added: "2026-04-16" date_updated: "2026-04-25" --- # Frontend Development Guidelines ## Overview This public intake copy packages `plugins/antigravity-awesome-skills/skills/frontend-dev-guidelines` from `https://github.com/sickn33/antigravity-awesome-skills` into the native Omni Skills editorial shape without hiding its origin. Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow. This intake keeps the copied upstream files intact and uses the `external_source` block in `metadata.json` plus `ORIGIN.md` as the provenance anchor for review. # Frontend Development Guidelines (React · TypeScript · Suspense-First · Production-Grade) You are a senior frontend engineer operating under strict architectural and performance standards. Your goal is to build scalable, predictable, and maintainable React applications using: Suspense-first data fetching Feature-based code organization Strict TypeScript discipline Performance-safe defaults This skill defines how frontend code must be written, not merely how it can be written. --- Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: 2. Core Architectural Doctrine (Non-Negotiable), 4. Quick Start Checklists, 5. Import Aliases (Required), 6. Component Standards, 7. Data Fetching Doctrine, 9. Styling Standards (MUI v7). ## When to Use This Skill Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request. - Creating components or pages - Adding new features - Fetching or mutating data - Setting up routing - Styling with MUI - Addressing performance issues ## Operating Table | Situation | Start here | Why it matters | | --- | --- | --- | | First-time use | `metadata.json` | Confirms repository, branch, commit, and imported path through the `external_source` block before touching the copied workflow | | Provenance review | `ORIGIN.md` | Gives reviewers a plain-language audit trail for the imported source | | Workflow execution | `resources/common-patterns.md` | Starts with the smallest copied file that materially changes execution | | Supporting context | `resources/complete-examples.md` | Adds the next most relevant copied source file without loading the entire package | | Handoff decision | `## Related Skills` | Helps the operator switch to a stronger native skill when the task drifts | ## Workflow This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow. 1. Folder-based routing only 2. Lazy load route components 3. Breadcrumb metadata via loaders 4. Confirm the user goal, the scope of the imported workflow, and whether this skill is still the right router for the task. 5. Read the overview and provenance files before loading any copied upstream support files. 6. Load only the references, examples, prompts, or scripts that materially change the outcome for the current request. 7. Execute the upstream workflow while keeping provenance and source boundaries explicit in the working notes. ### Imported Workflow Notes #### Imported: 8. Routing Standards (TanStack Router) * Folder-based routing only * Lazy load route components * Breadcrumb metadata via loaders ```ts export const Route = createFileRoute('/my-route/')({ component: MyPage, loader: () => ({ crumb: 'My Route' }), }); ``` --- #### Imported: 2. Core Architectural Doctrine (Non-Negotiable) ### 1. Suspense Is the Default * `useSuspenseQuery` is the **primary** data-fetching hook * No `isLoading` conditionals * No early-return spinners ### 2. Lazy Load Anything Heavy * Routes * Feature entry components * Data grids, charts, editors * Large dialogs or modals ### 3. Feature-Based Organization * Domain logic lives in `features/` * Reusable primitives live in `components/` * Cross-feature coupling is forbidden ### 4. TypeScript Is Strict * No `any` * Explicit return types * `import type` always * Types are first-class design artifacts --- ## Examples ### Example 1: Ask for the upstream workflow directly ```text Use @frontend-dev-guidelines-v2 to handle . Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer. ``` **Explanation:** This is the safest starting point when the operator needs the imported workflow, but not the entire repository. ### Example 2: Ask for a provenance-grounded review ```text Review @frontend-dev-guidelines-v2 against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why. ``` **Explanation:** Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection. ### Example 3: Narrow the copied support files before execution ```text Use @frontend-dev-guidelines-v2 for . Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding. ``` **Explanation:** This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default. ### Example 4: Build a reviewer packet ```text Review @frontend-dev-guidelines-v2 using the copied upstream files plus provenance, then summarize any gaps before merge. ``` **Explanation:** This is useful when the PR is waiting for human review and you want a repeatable audit packet. ## Best Practices Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution. - Keep the imported skill grounded in the upstream repository; do not invent steps that the source material cannot support. - Prefer the smallest useful set of support files so the workflow stays auditable and fast to review. - Keep provenance, source commit, and imported file paths visible in notes and PR descriptions. - Point directly at the copied upstream files that justify the workflow instead of relying on generic review boilerplate. - Treat generated examples as scaffolding; adapt them to the concrete task before execution. - Route to a stronger native skill when architecture, debugging, design, or security concerns become dominant. ## Troubleshooting ### Problem: The operator skipped the imported context and answered too generically **Symptoms:** The result ignores the upstream workflow in `plugins/antigravity-awesome-skills/skills/frontend-dev-guidelines`, fails to mention provenance, or does not use any copied source files at all. **Solution:** Re-open `metadata.json`, `ORIGIN.md`, and the most relevant copied upstream files. Check the `external_source` block first, then restate the provenance before continuing. ### Problem: The imported workflow feels incomplete during review **Symptoms:** Reviewers can see the generated `SKILL.md`, but they cannot quickly tell which references, examples, or scripts matter for the current task. **Solution:** Point at the exact copied references, examples, scripts, or assets that justify the path you took. If the gap is still real, record it in the PR instead of hiding it. ### Problem: The task drifted into a different specialization **Symptoms:** The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better. **Solution:** Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind. ## Related Skills - `@00-andruia-consultant` - Use when the work is better handled by that native specialization after this imported skill establishes context. - `@00-andruia-consultant-v2` - Use when the work is better handled by that native specialization after this imported skill establishes context. - `@10-andruia-skill-smith` - Use when the work is better handled by that native specialization after this imported skill establishes context. - `@10-andruia-skill-smith-v2` - Use when the work is better handled by that native specialization after this imported skill establishes context. ## Additional Resources Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding. | Resource family | What it gives the reviewer | Example path | | --- | --- | --- | | `references` | copied reference notes, guides, or background material from upstream | `references/n/a` | | `examples` | worked examples or reusable prompts copied from upstream | `examples/n/a` | | `scripts` | upstream helper scripts that change execution or validation | `scripts/n/a` | | `agents` | routing or delegation notes that are genuinely part of the imported package | `agents/n/a` | | `assets` | supporting assets or schemas copied from the source package | `assets/n/a` | - [common-patterns.md](resources/common-patterns.md) - [complete-examples.md](resources/complete-examples.md) - [component-patterns.md](resources/component-patterns.md) - [data-fetching.md](resources/data-fetching.md) - [file-organization.md](resources/file-organization.md) - [loading-and-error-states.md](resources/loading-and-error-states.md) ### Imported Reference Notes #### Imported: 1. Frontend Feasibility & Complexity Index (FFCI) Before implementing a component, page, or feature, assess feasibility. ### FFCI Dimensions (1–5) | Dimension | Question | | --------------------- | ---------------------------------------------------------------- | | **Architectural Fit** | Does this align with feature-based structure and Suspense model? | | **Complexity Load** | How complex is state, data, and interaction logic? | | **Performance Risk** | Does it introduce rendering, bundle, or CLS risk? | | **Reusability** | Can this be reused without modification? | | **Maintenance Cost** | How hard will this be to reason about in 6 months? | ### Score Formula ``` FFCI = (Architectural Fit + Reusability + Performance) − (Complexity + Maintenance Cost) ``` **Range:** `-5 → +15` ### Interpretation | FFCI | Meaning | Action | | --------- | ---------- | ----------------- | | **10–15** | Excellent | Proceed | | **6–9** | Acceptable | Proceed with care | | **3–5** | Risky | Simplify or split | | **≤ 2** | Poor | Redesign | --- #### Imported: 4. Quick Start Checklists ### New Component Checklist * [ ] `React.FC` with explicit props interface * [ ] Lazy loaded if non-trivial * [ ] Wrapped in `` * [ ] Uses `useSuspenseQuery` for data * [ ] No early returns * [ ] Handlers wrapped in `useCallback` * [ ] Styles inline if <100 lines * [ ] Default export at bottom * [ ] Uses `useMuiSnackbar` for feedback --- ### New Feature Checklist * [ ] Create `features/{feature-name}/` * [ ] Subdirs: `api/`, `components/`, `hooks/`, `helpers/`, `types/` * [ ] API layer isolated in `api/` * [ ] Public exports via `index.ts` * [ ] Feature entry lazy loaded * [ ] Suspense boundary at feature level * [ ] Route defined under `routes/` --- #### Imported: 5. Import Aliases (Required) | Alias | Path | | ------------- | ---------------- | | `@/` | `src/` | | `~types` | `src/types` | | `~components` | `src/components` | | `~features` | `src/features` | Aliases must be used consistently. Relative imports beyond one level are discouraged. --- #### Imported: 6. Component Standards ### Required Structure Order 1. Types / Props 2. Hooks 3. Derived values (`useMemo`) 4. Handlers (`useCallback`) 5. Render 6. Default export ### Lazy Loading Pattern ```ts const HeavyComponent = React.lazy(() => import('./HeavyComponent')); ``` Always wrapped in ``. --- #### Imported: 7. Data Fetching Doctrine ### Primary Pattern * `useSuspenseQuery` * Cache-first * Typed responses ### Forbidden Patterns ❌ `isLoading` ❌ manual spinners ❌ fetch logic inside components ❌ API calls without feature API layer ### API Layer Rules * One API file per feature * No inline axios calls * No `/api/` prefix in routes --- #### Imported: 9. Styling Standards (MUI v7) ### Inline vs Separate * `<100 lines`: inline `sx` * `>100 lines`: `{Component}.styles.ts` ### Grid Syntax (v7 Only) ```tsx // ✅ // ❌ ``` Theme access must always be type-safe. --- #### Imported: 10. Loading & Error Handling ### Absolute Rule ❌ Never return early loaders ✅ Always rely on Suspense boundaries ### User Feedback * `useMuiSnackbar` only * No third-party toast libraries --- #### Imported: 11. Performance Defaults * `useMemo` for expensive derivations * `useCallback` for passed handlers * `React.memo` for heavy pure components * Debounce search (300–500ms) * Cleanup effects to avoid leaks Performance regressions are bugs. --- #### Imported: 12. TypeScript Standards * Strict mode enabled * No implicit `any` * Explicit return types * JSDoc on public interfaces * Types colocated with feature --- #### Imported: 13. Canonical File Structure ``` src/ features/ my-feature/ api/ components/ hooks/ helpers/ types/ index.ts components/ SuspenseLoader/ CustomAppBar/ routes/ my-route/ index.tsx ``` --- #### Imported: 14. Canonical Component Template ```ts import React, { useState, useCallback } from 'react'; import { Box, Paper } from '@mui/material'; import { useSuspenseQuery } from '@tanstack/react-query'; import { featureApi } from '../api/featureApi'; import type { FeatureData } from '~types/feature'; interface MyComponentProps { id: number; onAction?: () => void; } export const MyComponent: React.FC = ({ id, onAction }) => { const [state, setState] = useState(''); const { data } = useSuspenseQuery({ queryKey: ['feature', id], queryFn: () => featureApi.getFeature(id), }); const handleAction = useCallback(() => { setState('updated'); onAction?.(); }, [onAction]); return ( {/* Content */} ); }; export default MyComponent; ``` --- #### Imported: 15. Anti-Patterns (Immediate Rejection) ❌ Early loading returns ❌ Feature logic in `components/` ❌ Shared state via prop drilling instead of hooks ❌ Inline API calls ❌ Untyped responses ❌ Multiple responsibilities in one component --- #### Imported: 16. Integration With Other Skills * **frontend-design** → Visual systems & aesthetics * **page-cro** → Layout hierarchy & conversion logic * **analytics-tracking** → Event instrumentation * **backend-dev-guidelines** → API contract alignment * **error-tracking** → Runtime observability --- #### Imported: 17. Operator Validation Checklist Before finalizing code: * [ ] FFCI ≥ 6 * [ ] Suspense used correctly * [ ] Feature boundaries respected * [ ] No early returns * [ ] Types explicit and correct * [ ] Lazy loading applied * [ ] Performance safe --- #### Imported: 18. Skill Status **Status:** Stable, opinionated, and enforceable **Intended Use:** Production React codebases with long-term maintenance horizons #### Imported: Limitations - Use this skill only when the task clearly matches the scope described above. - Do not treat the output as a substitute for environment-specific validation, testing, or expert review. - Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.