Landing Page Copywriter
julianromli/ai-skills
Write high-converting landing page copy using proven frameworks like PAS (Problem-Agitate-Solution), AIDA, and StoryBrand.
Use this skill before asserting that a CSS, HTML or accessibility capability is available, unavailable, or the right tool — it carries dated, refreshable platform facts and refuses to let stale…
Install Web Platform Baseline
$ npx skills add WrongStack/WrongStack --skill web-platform-baseline -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install WrongStack/WrongStack web-platform-baseline --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/WrongStack/WrongStack.git skills-src && mkdir -p .claude/skills && cp -r skills-src/packages/core/skills/web-platform-baseline .claude/skills/web-platform-baseline && 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 "web-platform-baseline" agent skill from https://github.com/WrongStack/WrongStack/tree/main/packages/core/skills/web-platform-baseline into .claude/skills/web-platform-baseline/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-platform-baseline", 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/WrongStack/WrongStack/tree/main/packages/core/skills/web-platform-baselineType 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 WrongStack/WrongStack --skill web-platform-baseline -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install WrongStack/WrongStack web-platform-baseline --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/WrongStack/WrongStack.git skills-src && mkdir -p .agents/skills && cp -r skills-src/packages/core/skills/web-platform-baseline .agents/skills/web-platform-baseline && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "web-platform-baseline" agent skill from https://github.com/WrongStack/WrongStack/tree/main/packages/core/skills/web-platform-baseline into .agents/skills/web-platform-baseline/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-platform-baseline", 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 WrongStack/WrongStack --skill web-platform-baseline -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install WrongStack/WrongStack web-platform-baseline --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/WrongStack/WrongStack.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/packages/core/skills/web-platform-baseline .cursor/skills/web-platform-baseline && 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 "web-platform-baseline" agent skill from https://github.com/WrongStack/WrongStack/tree/main/packages/core/skills/web-platform-baseline into .cursor/skills/web-platform-baseline/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-platform-baseline", 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/WrongStack/WrongStack.git --path packages/core/skills/web-platform-baseline--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 WrongStack/WrongStack --skill web-platform-baseline -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install WrongStack/WrongStack web-platform-baseline --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/WrongStack/WrongStack.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/packages/core/skills/web-platform-baseline .gemini/skills/web-platform-baseline && 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 "web-platform-baseline" agent skill from https://github.com/WrongStack/WrongStack/tree/main/packages/core/skills/web-platform-baseline into .gemini/skills/web-platform-baseline/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-platform-baseline", 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 WrongStack/WrongStack web-platform-baselineInstalls 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 WrongStack/WrongStack --skill web-platform-baseline -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/WrongStack/WrongStack.git skills-src && mkdir -p .github/skills && cp -r skills-src/packages/core/skills/web-platform-baseline .github/skills/web-platform-baseline && 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 "web-platform-baseline" agent skill from https://github.com/WrongStack/WrongStack/tree/main/packages/core/skills/web-platform-baseline into .github/skills/web-platform-baseline/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-platform-baseline", 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 WrongStack/WrongStack --skill web-platform-baseline -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install WrongStack/WrongStack web-platform-baseline --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/WrongStack/WrongStack.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/packages/core/skills/web-platform-baseline .opencode/skills/web-platform-baseline && 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 "web-platform-baseline" agent skill from https://github.com/WrongStack/WrongStack/tree/main/packages/core/skills/web-platform-baseline into .opencode/skills/web-platform-baseline/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-platform-baseline", 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
web-platform-baseline- GitHub stars
- 368
- Token cost
- ~1.6k tokens
- SKILL.md length
- 791 words
- Files
- 4 (incl. references)
- Skills in repo
- 38
- Repo updated
- First seen
- Licence
- MIT
At a glance
Use this skill before asserting that a CSS, HTML or accessibility capability is available, unavailable, or the right tool — it carries dated, refreshable platform facts and refuses to let stale…
- Works in 2 steps: Stale caution — writing a media-query… → Stale confidence — asserting support for…
- Tasks that involve Positioning and messaging
- SKILL.md covers Why this exists, The staleness rule —…, What's in here and Rules, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Web Platform Baseline is an agent skill from WrongStack/WrongStack. Use this skill before asserting that a CSS, HTML or accessibility capability is available, unavailable, or the right tool — it carries dated, refreshable platform facts and refuses to let stale knowledge be stated as current. Triggers: user says "container query", "can I use", "browser support", "modern CSS", ":has", "subgrid", "view transition", "popover", "dialog", "anchor positioning", "scroll-driven animation", "baseline", "polyfill", "is it supported", "fallback needed".
Its SKILL.md is about 1.6k tokens, which your agent loads only when the skill is triggered. The skill folder holds 4 other files, including reference files (for example `references/a11y.md`, `references/css.md` and `references/html.md`).
It sits in Frontend & Design, covering Positioning and messaging. The repository describes itself as: An AI coding agent that reads your code, edits files, runs commands, and reasons through bugs — across a terminal REPL, a full-screen TUI, and a browser UI, while you keep your… The licence is MIT.
When your agent uses it
- Tasks that involve Positioning and messaging
Example prompts
- “container query”
- “can I use”
- “browser support”
- “/web-platform-baseline”
Workflow steps
2 steps, taken from the first numbered list in SKILL.md.
- Stale caution — writing a media-query ladder, a JS resize observer, or a
- Stale confidence — asserting support for something that is still behind
What it can do on your machine
Read from SKILL.md and the folder at commit ec76a20. 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
No scripts in the folder and no shell commands in SKILL.md.
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
Web Platform Baseline loads about 1.6k tokens when it runs, and up to ~5.2k if it reads all its reference files. Until then it costs about 126 tokens; SKILL.md has 791 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); files beside SKILL.md are not scanned.
SKILL.md
The full file from WrongStack/WrongStack at commit ec76a20, republished under its MIT licence (© WrongStack). 791 words, ~1,587 tokens.
Download SKILL.mdSave it as
.claude/skills/web-platform-baseline/SKILL.md (or your agent's skills folder). This skill also uses 3 other files; get the full folder from GitHub.- name
- web-platform-baseline
- description
- Use this skill before asserting that a CSS, HTML or accessibility capability is available, unavailable, or the right tool — it carries dated, refreshable platform facts and refuses to let stale knowledge be stated as current. Triggers: user says "container query", "can I use", "browser support", "modern CSS", ":has", "subgrid", "view transition", "popover", "dialog", "anchor positioning", "scroll-driven animation", "baseline", "polyfill", "is it supported", "fallback needed".
- version
- 1.0.0
- required-capabilities
- filesystem.read
- required-tools
- skill, search, fetch
- optional-capabilities
- web.research
Web Platform Baseline — WrongStack
Why this exists
Two failure modes, both expensive:
- Stale caution — writing a media-query ladder, a JS resize observer, or a z-index hack for something the platform has shipped for years. This is the most common source of dated-looking, over-engineered UI code.
- Stale confidence — asserting support for something that is still behind a flag, or naming a syntax that changed during standardization.
Model training data guarantees both. This skill is the correction: every fact lives in a dated reference file, and a fact past its shelf life may not be asserted without a live check.
The staleness rule — non-negotiable
Every reference file in this skill starts with a verified: date.
<!-- verified: 2026-09-16 | sources: MDN, web.dev Baseline, caniuse -->Before you assert any fact from a reference:
Age of verified: | What you may do |
|---|---|
| ≤ 90 days | State it as current. Cite the file. |
| > 90 days | State it as "as of <date>", and verify with search / fetch before it drives an architectural decision. |
| > 180 days, or the fact decides the architecture | Verify first, then answer. Update the reference file with the new date and the corrected fact. |
Never silently "refresh" a fact from memory. A date you cannot evidence is a guess wearing a date.
This has already happened once, in this file's own references. The first
revision of css.md and html.md was written from model knowledge and stamped
with that day's date without a single live check. A later verification pass found
7 of 14 tiers wrong — anchor positioning, text-box-trim and field-sizing
were marked unavailable months after they had reached Baseline (the "stale
caution" failure, which makes code hand-roll what the platform already does),
while scroll-driven animations, text-wrap: pretty and the Popover API were
marked more available than they are (the "stale confidence" failure). So: when
you write a verified: date, the check must have happened in that turn, and the
sources must be named on the line. If you cannot verify a row, mark it
UNVERIFIED and say so rather than guessing a tier. The same rule applies to anything you remember about
framework defaults (Tailwind, React, the kit stacks) — those live in
tech-stack and research-web, and rot the same way.
When you do verify, use the primary sources in this order: MDN (syntax and
semantics), web.dev Baseline (availability tier), caniuse (version
detail), the spec (when behavior is genuinely contested). Two agreeing
sources minimum, per the research-web rules.
What's in here
Load on demand — do not paste these into a plan wholesale:
Load these with the skill tool — skill({ name: "web-platform-baseline", resource: "references/<file>.md" }):
references/css.md— layout, container queries,:has(), subgrid, nesting,color-mix(), OKLCH,text-wrap, cascade layers, scroll-driven animation,@starting-style, anchor positioningreferences/html.md—<dialog>, popover,<details>interop, form controls,field-sizing, lazy/priority hints, view transitionsreferences/a11y.md— WCAG 2.2 additions, focus appearance, target size,prefers-*queries, accessible names, live regions
Show full SKILL.md (328 more words)Show less
Rules
- Never assert browser support from memory. Cite a reference file (with its date) or verify live.
- Prefer the platform. If CSS or HTML does it natively, a JS dependency is a regression. Reach for a library only when the native path is genuinely missing a capability the product needs — and say which one.
- Progressive enhancement over polyfill.
@supports, a sane fallback, and the modern path on top. Shipping a polyfill for a Baseline-available feature is dead weight. - Availability tier, not a version list. Say "Baseline widely available" or "Baseline newly available (needs a fallback)" — version tables age badly and users rarely need them.
- When the answer is "it depends on your support target", ask. Do not assume evergreen-only, and do not assume enterprise IE-era constraints.
- Correct the file, not just the answer. If you verify a fact and find the
reference stale, update it and its
verified:date in the same turn. A correction you don't write down will be re-derived from scratch next week.
Applying it
The common wins, which the references cover in detail:
| Old reflex | Current platform |
|---|---|
| JS resize observer to restyle a component | container queries |
| Parent-state class toggling in JS | :has() |
| Nested grid hacks for alignment across cards | subgrid |
| Manual focus-trap library for a modal | <dialog> + showModal() |
| Positioned dropdown with a JS collision library | popover + anchor positioning |
scroll listener driving an animation | scroll-driven animations |
| SASS just for nesting and variables | native nesting + custom properties |
Ragged headline hand-fixed with <br> | text-wrap: balance |
| Hand-mixed hover/disabled color variants | color-mix() on the kit token |
Each of these makes the code both shorter and less generated-looking — the hand-rolled version of a platform feature is itself a tell.
Skills in scope
design-craft— the composition rules these capabilities servedesign-system— kit tokens; platform features consume tokens, never literalsdesign-critique— auditing an existing UI against current practiceresearch-web— the verification workflow when a fact is staletech-stack— framework/package version currency (the same rot, different layer)
© WrongStack, 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 3 other files (references) in packages/core/skills/web-platform-baseline of WrongStack/WrongStack.
- SKILL.md
- references/a11y.md
- references/css.md
- references/html.md
Open the folder on GitHubat commit ec76a20
Compare with similar skills
Web Platform Baseline 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 |
|---|---|---|---|---|---|---|
| Web Platform Baseline this skillWrongStack/WrongStack | 368 | — | ~1.6k | Automated safety check: Pass | MIT | |
| Landing Page Copywriterjulianromli/ai-skills | 191 | 2 repos | ~1.4k | Automated safety check: Pass | None | |
| Ads Competitorszubair-trabzada/ai-ads-claude | 267 | — | ~4.9k | Automated safety check: Pass | MIT | |
| Brand SystemsHermeticOrmus/LibreUIUX-Claude-Code | 111 | — | ~2.3k | Automated safety check: Pass | MIT | |
| Base UI Reactsecondsky/claude-skills | 227 | — | ~1.9k | Automated safety check: Pass | MIT | |
| Design Archivistcuriositech/some_claude_skills | 243 | 1 repos | ~1.6k | Automated safety check: Pass | MIT |
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Related
Categories
Questions about Web Platform Baseline
What does Web Platform Baseline do?
Use this skill before asserting that a CSS, HTML or accessibility capability is available, unavailable, or the right tool — it carries dated, refreshable platform facts and refuses to let stale…. Web Platform Baseline is an agent skill from WrongStack/WrongStack. Use this skill before asserting that a CSS, HTML or accessibility capability is available, unavailable, or the right tool — it carries dated, refreshable platform facts and refuses to let stale knowledge be stated as current.
When should I use Web Platform Baseline?
Web Platform Baseline fits situations like: tasks that involve Positioning and messaging.
How do I install Web Platform Baseline in Claude Code?
Run `npx skills add WrongStack/WrongStack --skill web-platform-baseline -a claude-code`. Or copy the skill folder (packages/core/skills/web-platform-baseline in WrongStack/WrongStack) into .claude/skills/web-platform-baseline in your project. Claude Code loads it when a task matches its description.
How do I install Web Platform Baseline in Codex?
Run `npx skills add WrongStack/WrongStack --skill web-platform-baseline -a codex`. Or copy the skill folder (packages/core/skills/web-platform-baseline in WrongStack/WrongStack) into .agents/skills/web-platform-baseline in your project. Codex loads it when a task matches its description.
Can I use Web Platform Baseline 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 WrongStack/WrongStack --skill web-platform-baseline -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/web-platform-baseline, .gemini/skills/web-platform-baseline, .github/skills/web-platform-baseline and .opencode/skills/web-platform-baseline in your project.
What does Web Platform Baseline need to run?
SKILL.md names no scripts, command-line tools or credentials: Web Platform Baseline is instructions for the agent only.
Does Web Platform Baseline 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 Web Platform Baseline 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. Review the folder before installing.
What licence does Web Platform Baseline use?
Web Platform Baseline is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Web Platform Baseline use?
About 1.6k tokens (SKILL.md is roughly 6.3k 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 3.6k tokens, read only when the agent opens those files.
What are the alternatives to Web Platform Baseline?
Skills that share tags, products or a category with Web Platform Baseline: Landing Page Copywriter (julianromli/ai-skills, 191 stars), Ads Competitors (zubair-trabzada/ai-ads-claude, 267 stars), Brand Systems (HermeticOrmus/LibreUIUX-Claude-Code, 111 stars) and Base UI React (secondsky/claude-skills, 227 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Web Platform Baseline?
WrongStack (a GitHub organization) maintains it in WrongStack/WrongStack, which has 368 GitHub stars. The repository holds 38 skills in this directory. The repository was last updated on October 6, 2026.
Source: WrongStack/WrongStack on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.