Html It

/html-it — HTML output skill

Stop reaching for markdown. When the agent is asked to produce a doc, plan, report, review, design, prototype, dashboard, or editor — make it HTML instead. Higher information density, easier to read, easier to share, and (at levels 3-4) interactive.

This skill encodes the four levels of HTML output, the patterns that work at each level, and the rules that keep agent-generated HTML from looking AI-slop.

> Credit: Framework and use-case taxonomy from Thariq Shihipar (@trq212) of the Anthropic Claude Code team. Original article: Using Claude Code — The Unreasonable Effectiveness of HTML. Examples gallery: thariqs.github.io/html-effectiveness. This skill is one community implementation of his ideas — go read the source.

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When to reach for HTML over markdown

Markdown's default. HTML wins when any of these are true:

• The output is over ~100 lines (markdown stops getting read)
• It needs charts, tables, SVG diagrams, side-by-sides, or spatial layout
• It needs to be shared (HTML is a link; markdown is an attachment)
• The reader will manipulate it (sliders, toggles, drags, picks)
• It synthesises data from multiple sources (filesystem, MCPs, git, browser)
• It will exist for one use and then be thrown away

Markdown stays better for: tiny notes, commit messages, README first-pass, things that need to round-trip through git diffs.

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The Four Levels

Each level is a strict superset of the last in capability and effort. Most agent output stops at Level 1. The unlock is recognising when you should be at 3 or 4.

Level 1 — Static Doc

HTML as a better markdown. One-way, read-only. Replaces a long .md file with something readable.

Use cases: specs, research reports, explainers, incident write-ups, weekly status, plans, PR write-ups, summaries.

Defining moves:

• Headings, sections, intro/TL;DR up top
• Body text with serif typography (looks like a magazine, not a wiki)
• Pull-quotes, callouts, footnotes
• Mobile responsive — viewer might open on phone
• Sticky table of contents for anything > 1500 words

Example prompt: > "Create a thorough implementation plan as an HTML file. Headers, TL;DR at top, key code snippets inline, sticky TOC on the left. Easy to digest."

Level 2 — Visual Artifact

HTML adds visual density. Still read-only. Information that text can't convey lands here.

Use cases: design systems, slide decks, flowcharts, dashboards (snapshot view), comparison tables, SVG illustrations, component galleries, before/after pairs.

Defining moves:

• SVG for diagrams (never ASCII art, never PNG when SVG works)
• Tables for any comparison or matrix
• Spatial layout — grids, side-by-sides, columns
• Inline charts (`` bar/line/donut, no charting library)
• Colour as data (severity badges, diff annotations, heatmaps)
• Slide-deck format with scroll-snap for talks

Example prompt: > "Read the rate limiter code and produce a single HTML explainer page: a token-bucket SVG flow diagram at the top, 3-4 annotated code snippets, gotchas section at the bottom. Optimised for someone reading it once."

Level 3 — Two-Way Interactive

HTML the reader can manipulate. Sliders, toggles, drags, inline edits. The export pattern is mandatory: every Level 3 artifact ends with a button that turns the manipulated state back into a prompt or structured output the agent can act on.

Use cases: design tuning (animations, colours, easing curves), parameter sweeps, A/B option pickers, prompt iteration with live preview, draft review with inline comments, picking values from a range.

Defining moves:

• Sliders, toggles, dropdowns, draggable cards
• Live preview that re-renders on input
• Export button at the end — Copy as prompt / Copy as JSON / Copy as markdown. Uses navigator.clipboard.writeText. Without it the level collapses to a toy.
• State stays in the DOM — no backend. Reload = reset is fine for throwaways.
• Inline edits use contenteditable or `` directly on the page

Example prompt: > "I'm tuning this system prompt. Make a side-by-side HTML editor: editable prompt on the left with variable slots highlighted, three sample inputs on the right that re-render the filled template live. Add a character counter and a Copy button."

Level 4 — Throwaway Tool

A purpose-built mini-app for one task. Looks like a real product but exists for this one piece of data. Always ends with an export back to Claude.

Use cases: triage boards (drag tickets across columns), feature-flag editors with dependency warnings, dataset curation (approve/reject/tag rows), annotation tools, config editors with validation, prompt-template tuners, file-comparison views, manual data entry with constraints.

Defining moves:

• Multi-panel layout (toolbar / sidebar / canvas / inspector)
• Domain-specific UI: kanban columns, file tree, diff view, editable table
• Validation and feedback inline (warnings, errors, dependency hints)
• Keyboard shortcuts where useful
• Export button is the unlock — Copy as markdown / Copy diff / Copy as JSON. Without it this is a useless one-off. With it, the reader's manual work becomes Claude's next prompt.
• Throwaway aesthetic — don't over-engineer. No build step, no framework, single file.

Example prompt: > "I need to reprioritise these 30 Linear tickets. Make an HTML file with each ticket as a draggable card across Now / Next / Later / Cut columns. Pre-sort by your best guess. Add a 'Copy as markdown' button that exports the final ordering with a one-line rationale per bucket."

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Best Practices (scoured from Thariq's 20 examples)

Design system that doesn't scream "I'm AI-generated"

Colour palette — print-mag warm neutrals beat tech-dark. Default to:

--ivory:  #FAF9F5;   /* background */
--paper:  #FFFFFF;   /* card surface */
--slate:  #141413;   /* body text */
--clay:   #D97757;   /* accent (warm orange) */
--clay-d: #B85C3E;   /* accent hover */
--oat:    #E3DACC;   /* underline / subtle dividers */
--olive:  #788C5D;   /* positive / success */
--g100:   #F0EEE6;
--g200:   #E6E3DA;
--g300:   #D1CFC5;
--g500:   #87867F;
--g700:   #3D3D3A;

Override only if the brand requires it. Dark mode is fine for editor-style Level 4 tools — keep the warm-neutral instinct (orange/amber accents, not neon).

Type stack — three families, distinct jobs:

--serif: ui-serif, Georgia, "Times New Roman", serif;   /* H1 + display */
--sans:  system-ui, -apple-system, "Segoe UI", sans;    /* body */
--mono:  ui-monospace, "SF Mono", Menlo, Consolas;      /* eyebrow + code + meta */

Typographic moves that elevate immediately:

• font-size: clamp(38px, 5.4vw, 62px) for H1 — responsive without media queries
• Italic accent on the key word in a serif H1: The unreasonable effectiveness
• Eyebrow label above titles — small mono, uppercase, 0.08-0.12em letter-spacing, with a 24px clay bar before it
• letter-spacing: -0.018em on display sizes
• line-height: 1.06 on display, 1.55 on body

Layout

• Max-width 1120-1180px wrap, padding: 48px 32px 64px
• Sections separated by border-bottom: 1.5px solid var(--g300) + 56-80px breathing room
• 2-column hero: text left, illustration right, collapse to 1-col at 880px
• For editor patterns (Level 4): sticky toolbar at top, full-bleed canvas, optional inspector panel right

Interaction patterns (Level 3-4)

The Export button is the contract. Every interactive HTML must end with a button labelled exactly what it exports:

Copy as markdown

Standard handler:

const btn = document.getElementById('copyBtn');
btn.addEventListener('click', () => {
  const md = buildExport();
  navigator.clipboard.writeText(md).then(() => {
    btn.textContent = '✓ Copied';
    btn.classList.add('copied');
    setTimeout(() => {
      btn.textContent = 'Copy as markdown';
      btn.classList.remove('copied');
    }, 2000);
  });
});

Tri-state buttons for review patterns (approve / skip / blank) — cycle on click. Encode as data-state on the row, style via CSS.

Inline picks — for "choose A/B/C" UIs, make each option a clickable card that toggles a .picked class. Single pick per group.

Single-file discipline

• One .html file. Inline ` and `. No build step. No external CSS/JS deps except optional Google Fonts.
• All assets either inline SVG or data: URLs. No /img/foo.png folders.
• The file is the artifact — Jay (or the viewer) can email it, drop it in Slack, open it on a phone, archive it.

Anti-patterns to avoid

• Linear gradients on everything (AI-slop tell)
• Glassmorphism for documents (save it for product UIs)
• Icon libraries — use bespoke SVG or skip icons entirely
• Loading spinners (this isn't a web app, it's a doc)
• "Generated by AI on {date}" footers
• Animations longer than 200ms (jittery to read past)

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Recipes (this session's HTML artifacts, generalised)

Recipe — Interactive Review (Level 3)

For triaging N options visually with comments + status + clipboard export. Used in this session for hook variations and b-roll review.

Anatomy:

1. Topline seed block — show original input verbatim
2. Table or grid, one row per item
3. Variation cards per row (click to pick, single per row, .picked style)
4. Tri-state status button (blank → ✓ → ✗ → blank)
5. Comments textarea per row
6. Optional secondary pickers (style, tag, mode)
7. Live summary line at bottom (accumulates picks)
8. Export button — builds structured directive prompt, copies to clipboard

Canonical samples:

• C:/ROBO/agents/EDDO/output/hook-workshop-sample.html
• C:/ROBO/agents/EDDO/output/broll-review-html-vs-markdown.html

Recipe — Session Recap (Level 1)

Render the current conversation as a clean static doc. Original /html-it use case.

Sections:

1. Intent — what the user was trying to do (1 sentence)
2. Key turns — prompts + replies that mattered, skip throat-clearing
3. Decisions — explicit picks
4. Artifacts — file paths created/edited, clickable
5. Open threads — anything unresolved

Save location: C:/ROBO/output/html-it/{YYYY-MM-DD_HHMM}_{slug}.html. If a project is loaded via coordinate, also copy to the project folder.

Recipe — Comparison Explainer (Level 2)

For "X vs Y" lessons (Markdown vs HTML, before vs after). Side-by-side panels, inline SVG of the key concept, callout cards.

Anatomy:

• Eyebrow + H1 (italic accent on the pivot word)
• TL;DR card with the verdict
• Two panes side by side, full width on mobile
• Inline SVG of the mechanism if applicable
• Closing "When to use which" matrix

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How to invoke

Inside Robo (Eddo or any agent)

• User says /html-it, "html-it", "html this", "render as html", "build me an html for X"
• Agent picks the level (1-4) based on the task
• Generates a single .html file, saves to the right place, opens with start "" on Windows
• Confirms the path back to the user

Community version (share with viewers)

Public mirror at: github.com/robonuggets/html-it (prep — push pending Jay's go)

Install prompt for users:

I'm giving you a skill called html-it. Get the files with:

git clone https://github.com/robonuggets/html-it

Follow the README to set it up.
Recommend how it would best apply to my setup in plain language, and ask me
a few questions to clarify my intent before installing it.

Related skills

• tweak — Inject a live tweak panel into any HTML file (5 or 10 sliders), bake selected values back into source CSS. Pairs with Level 3/4 outputs from html-it. Community version: github.com/robonuggets/skills.
• master-slides — for slide-deck HTML specifically (Level 2). Different stylistic system (paper typography + isometric graphics).

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Rules

• Pick a level explicitly at the top of the response: "Using html-it Level 3 (Two-Way Interactive)" — same upfront-skill-signal rule as packaging.
• One file. Always. Inline CSS, inline JS, inline SVG. No asset folder. No build step.
• Mobile responsive by default. Test at 360px and 1200px.
• Export button is mandatory at Level 3+. Without it, an interactive HTML is a toy.
• Don't summarise away the substance. If rendering a conversation or doc, preserve actual phrasing of important content.
• Skip system-reminders, tool-call noise, meta chatter when extracting source content.
• Match the level to the task. A status report doesn't need sliders; a triage board doesn't work without them.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: robonuggets
• Source: robonuggets/html-it
• License: MIT

Install and usage instructions live in the source repository linked above.