Common Web Visual Testing
HoangNguyen0403/agent-skills-standard
Standardizes visual audits, responsive design, and behavioral testing for web apps.
Build and maintain web frontends — component architecture, state management, API integration, responsive layout, client-side performance, and frontend testing patterns.
Install Frontend Engineering
$ npx skills add magnus919/agent-skills --skill frontend-engineering -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install magnus919/agent-skills frontend-engineering --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/magnus919/agent-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/frontend-engineering .claude/skills/frontend-engineering && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "frontend-engineering" agent skill from https://github.com/magnus919/agent-skills/tree/main/frontend-engineering into .claude/skills/frontend-engineering/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "frontend-engineering", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/magnus919/agent-skills/tree/main/frontend-engineeringType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add magnus919/agent-skills --skill frontend-engineering -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install magnus919/agent-skills frontend-engineering --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/magnus919/agent-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/frontend-engineering .agents/skills/frontend-engineering && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "frontend-engineering" agent skill from https://github.com/magnus919/agent-skills/tree/main/frontend-engineering into .agents/skills/frontend-engineering/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "frontend-engineering", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add magnus919/agent-skills --skill frontend-engineering -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install magnus919/agent-skills frontend-engineering --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/magnus919/agent-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/frontend-engineering .cursor/skills/frontend-engineering && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "frontend-engineering" agent skill from https://github.com/magnus919/agent-skills/tree/main/frontend-engineering into .cursor/skills/frontend-engineering/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "frontend-engineering", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/magnus919/agent-skills.git --path frontend-engineering--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add magnus919/agent-skills --skill frontend-engineering -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install magnus919/agent-skills frontend-engineering --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/magnus919/agent-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/frontend-engineering .gemini/skills/frontend-engineering && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "frontend-engineering" agent skill from https://github.com/magnus919/agent-skills/tree/main/frontend-engineering into .gemini/skills/frontend-engineering/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "frontend-engineering", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install magnus919/agent-skills frontend-engineeringInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add magnus919/agent-skills --skill frontend-engineering -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/magnus919/agent-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/frontend-engineering .github/skills/frontend-engineering && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "frontend-engineering" agent skill from https://github.com/magnus919/agent-skills/tree/main/frontend-engineering into .github/skills/frontend-engineering/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "frontend-engineering", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add magnus919/agent-skills --skill frontend-engineering -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install magnus919/agent-skills frontend-engineering --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/magnus919/agent-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/frontend-engineering .opencode/skills/frontend-engineering && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "frontend-engineering" agent skill from https://github.com/magnus919/agent-skills/tree/main/frontend-engineering into .opencode/skills/frontend-engineering/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "frontend-engineering", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
frontend-engineering- GitHub stars
- 115
- Token cost
- ~1.5k tokens
- SKILL.md length
- 609 words
- Files
- 12 (incl. scripts, references)
- Skills in repo
- 131
- Repo updated
- First seen
- Licence
- MIT
At a glance
Build and maintain web frontends — component architecture, state management, API integration, responsive layout, client-side performance, and frontend testing patterns.
- Backend service implementation
- SKILL.md covers The Frontend Engineer's Domain, Reference Files, Templates and Scripts, plus 1 more section
- Runs Python scripts from its folder
- Data engineering
What it does
Frontend Engineering is an agent skill from magnus919/agent-skills. Build and maintain web frontends — component architecture, state management, API integration, responsive layout, client-side performance, and frontend testing patterns. Framework agnostic, focused on web frontend implementation. Do not use for backend service implementation, data engineering, or platform infrastructure work.
Its SKILL.md is about 1.5k tokens, which your agent loads only when the skill is triggered. The skill folder holds 15 other files, including scripts and reference files (for example `README.md`, `evals/evals.json` and `references/api-integration.md`).
It sits in Frontend & Design, covering Frontend development, Responsive design and State management. It works with Playwright. The repository describes itself as: Curated collection of AI agent skills for Hermes and other agent frameworks. The licence is MIT.
When your agent uses it
- Backend service implementation
- Data engineering
- Platform infrastructure work
Example prompts
- “/frontend-engineering”
Requirements
- Python 3
What it can do on your machine
Read from SKILL.md and the folder at commit 22b4723. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 2 files in scripts/ (Python), which the agent can run.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Frontend Engineering loads about 1.5k tokens when it runs, and up to ~11k if it reads all its reference files. Until then it costs about 87 tokens; SKILL.md has 609 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
SKILL.md
The full file from magnus919/agent-skills at commit 22b4723, republished under its MIT licence (© magnus919). 609 words, ~1,481 tokens.
Download SKILL.mdSave it as
.claude/skills/frontend-engineering/SKILL.md (or your agent's skills folder). This skill also uses 11 other files; get the full folder from GitHub.- name
- frontend-engineering
- description
- Build and maintain web frontends — component architecture, state management, API integration, responsive layout, client-side performance, and frontend testing patterns. Framework agnostic, focused on web frontend implementation. Do not use for backend service implementation, data engineering, or platform infrastructure work.
- license
- MIT
- metadata.tags
- frontend, web, ui, components, state-management, performance, javascript, typescript, responsive, testing
- metadata.source_repo
- https://github.com/magnus919/hermes-profiles
Frontend Engineering Methodology
Frontend engineering is the craft of building the user-facing layer of applications — components, state management, API integration, responsive layout, and client-side performance. This methodology bridges UX design (user journeys, wireframes, accessibility standards) and quality validation (qa-methodology).
The Frontend Engineer's Domain
| You own | You don't own |
|---|---|
| Component implementation — UI component composition, props/state interfaces, rendering patterns, lifecycle | User journeys, wireframes, accessibility standards, interaction design — that's the product-design-and-ux |
| State management — client-side state architecture, data fetching patterns, caching, optimistic updates | API contract design — that's the api-design-and-evolution |
| API integration — frontend-to-backend data flow, auth flows (OAuth, JWT), real-time updates | Test strategy and automation — that's the QA-engineer |
| Responsive design implementation — layout systems, breakpoints, cross-device testing | Visual identity and brand guidelines — that's the brand-designer |
| Client-side performance — bundle optimization, lazy loading, Core Web Vitals, render optimization | Editorial content and copy — owned by the content and marketing team, outside this skill's scope |
| Frontend testing — component tests, integration tests, visual regression, accessibility tests | Code review and quality gates — that's the qa-methodology |
| E2E test scenarios and user-flow coverage for frontend features | Operating the browser test tool (Playwright) — authoring/running specs, selectors, network mocking, scraping — route to playwright |
| Mobile app implementation (iOS/Android/Flutter/React Native) | Mobile platform work — scaffolding, builds and code signing, device/emulator testing, store submission, mobile lifecycle — route to mobile-development; this skill owns web frontends |
| Build tooling — bundler config, TypeScript config, linting, formatting, dev environment | CI/CD pipeline infrastructure — that's the platform-engineer |
For React component and hooks work, load react; for Vite config, modes, plugins, and builds, load vite. This skill remains the owner of framework-neutral architecture and frontend strategy.
Reference Files
| Reference | When to load |
|---|---|
references/component-architecture.md | Designing component trees — composition patterns, props/state interfaces, lifecycle, accessibility fundamentals |
references/state-management.md | Choosing and implementing state management — client vs server state, data fetching, caching, optimistic updates |
references/api-integration.md | Connecting frontend to backend — API client design, auth token flow, error handling in the UI, real-time subscriptions |
references/responsive-layout-testing.md | Implementing responsive designs (layout system selection — Grid vs Flexbox vs Container Queries, breakpoint strategies, cross-device testing methodology) and testing frontend code (component testing with Testing Library, integration testing with Playwright/Cypress, visual regression, accessibility testing with axe-core and Lighthouse CI, test data management) |
references/performance.md | Optimizing client-side performance — Core Web Vitals, bundle analysis, code splitting, render optimization |
Show full SKILL.md (245 more words)Show less
Templates
| Template | When to Use |
|---|---|
templates/component-state-design-record.md | Designing a component tree and state ownership for a feature — decomposition, state scoping, data fetching, and error/loading UX |
templates/performance-budget.md | Defining performance targets — bundle byte budgets, Core Web Vitals budgets, measurement setup, and CI enforcement |
Scripts
| Script | When to Use |
|---|---|
scripts/bundle-budget-checker.py | Checking a bundle size report against total and per-chunk budgets; fails (exit 1) when a budget is exceeded, so CI can block performance regressions |
Core Principles
Components are the unit of composition, not pages — Design and build components as reusable, composable units. Pages are assembled from components, not built as monoliths. A well-designed component can be reused in contexts its creator never imagined.
Co-locate state with the components that need it — Not every piece of state belongs in a global store. Local state stays local. Server state is fetched and cached. Only truly shared application state belongs in a global context.
Design for every state, not just the happy path — Every data-dependent component has at least four states: loading, empty, error, and success. Designing for all four is not a nicety — it creates a resilient user experience.
Accessibility is not a feature, it's a requirement — Keyboard navigation, screen reader support, color contrast, and focus management are not enhancements. They are part of the implementation contract.
Performance is a UX concern — Every millisecond of load time, every layout shift, every janky interaction erodes user trust. Performance budgeting, bundle analysis, and render optimization are part of frontend engineering, not an afterthought.
© magnus919, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 11 other files (scripts, references) in frontend-engineering of magnus919/agent-skills.
- SKILL.md
- README.md
- evals/evals.json
- references/api-integration.md
- references/component-architecture.md
- references/performance.md
- references/responsive-layout-testing.md
- references/state-management.md
- scripts/bundle-budget-checker.py
- scripts/test_bundle_budget_checker.py
- templates/component-state-design-record.md
- templates/performance-budget.md
Open the folder on GitHubat commit 22b4723
Compare with similar skills
Frontend Engineering next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Frontend Engineering this skillmagnus919/agent-skills | 115 | — | ~1.5k | Automated safety check: Pass | MIT | |
| Common Web Visual TestingHoangNguyen0403/agent-skills-standard | 572 | — | ~760 | Automated safety check: Pass | MIT | |
| Oil Frontend Rulesoil-oil/oil-frontend | 131 | — | ~1.4k | Automated safety check: Pass | MIT | |
| Frontend Developeraiskillstore/marketplace | 433 | 7 repos | ~1.9k | Automated safety check: Pass | None | |
| Phase 6 UI Integrationww-w-ai/bkit-claude-code | 601 | — | ~4.3k | Automated safety check: Notes | Apache-2.0 | |
| Flutter Devaiskillstore/marketplace | 433 | 1 repos | ~1.3k | Automated safety check: Pass | MIT |
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Related
Works with
Categories
Questions about Frontend Engineering
What does Frontend Engineering do?
Build and maintain web frontends — component architecture, state management, API integration, responsive layout, client-side performance, and frontend testing patterns. Frontend Engineering is an agent skill from magnus919/agent-skills. Build and maintain web frontends — component architecture, state management, API integration, responsive layout, client-side performance, and frontend testing patterns.
When should I use Frontend Engineering?
Frontend Engineering fits situations like: backend service implementation; data engineering; platform infrastructure work.
How do I install Frontend Engineering in Claude Code?
Run `npx skills add magnus919/agent-skills --skill frontend-engineering -a claude-code`. Or copy the skill folder (frontend-engineering in magnus919/agent-skills) into .claude/skills/frontend-engineering in your project. Claude Code loads it when a task matches its description.
How do I install Frontend Engineering in Codex?
Run `npx skills add magnus919/agent-skills --skill frontend-engineering -a codex`. Or copy the skill folder (frontend-engineering in magnus919/agent-skills) into .agents/skills/frontend-engineering in your project. Codex loads it when a task matches its description.
Can I use Frontend Engineering in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add magnus919/agent-skills --skill frontend-engineering -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/frontend-engineering, .gemini/skills/frontend-engineering, .github/skills/frontend-engineering and .opencode/skills/frontend-engineering in your project.
What does Frontend Engineering need to run?
Going by SKILL.md and its folder, Frontend Engineering needs Python for the scripts in its folder. Our summary lists: Python 3.
Does Frontend Engineering access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Frontend Engineering safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does Frontend Engineering use?
Frontend Engineering is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Frontend Engineering use?
About 1.5k tokens (SKILL.md is roughly 5.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 9.8k tokens, read only when the agent opens those files.
What are the alternatives to Frontend Engineering?
Skills that share tags, products or a category with Frontend Engineering: Common Web Visual Testing (HoangNguyen0403/agent-skills-standard, 572 stars), Oil Frontend Rules (oil-oil/oil-frontend, 131 stars), Frontend Developer (aiskillstore/marketplace, 433 stars) and Phase 6 UI Integration (ww-w-ai/bkit-claude-code, 601 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Frontend Engineering?
magnus919 (a GitHub user) maintains it in magnus919/agent-skills, which has 115 GitHub stars. The repository holds 131 skills in this directory. The repository was last updated on October 10, 2026.
Source: magnus919/agent-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.