| name | design-newsletter-header |
| description | Generate a newsletter email header banner — pixel-exact 600×200 HTML canvas (the standard email-client safe-zone width). Self-contained, INLINE styles only (no external <style> blocks beyond <head>) for email-client compat. Intended to be screenshot to PNG and embedded as <img> in email — the rendered image is what readers see, regardless of their email client. Reads ./design/<brand-slug>/DESIGN.md and tokens.css. Triggers include "newsletter header", "email header for X", "email banner", "/newsletter-header". |
Skill: newsletter-header
Produces a 600×200 pixel-exact HTML canvas for use as a newsletter email header. The canvas is small — typography choices must be ruthless. Display sizes top out around 36–48px; meta around 11–14px. The artifact is meant to be screenshot to PNG and embedded as <img> in the email — the email client never sees raw HTML, so font and CSS quirks don't matter for delivery.
When to use
- User publishes a newsletter and needs a branded header banner image
- A
DESIGN.md exists for the brand
Inputs
- Required: brand slug, newsletter title or issue identifier (e.g. "Working notes — May 2026")
- Optional: issue number, dateline, tagline (max 6 words)
Output
./design/<brand-slug>/artifacts/newsletter-header-YYYY-MM-DD-<slug>.html
Steps
1. Verify brand exists
test -f ./design/<brand-slug>/tokens.css
If missing, stop and tell the user to run /design-system <brand-slug> first.
2. Gather the brief
Ask in one message:
1. Header text — the masthead string (max 6 words)
2. Optional issue number / dateline (e.g. "Issue 003 · 2026.05.02")
3. Optional tagline / subtitle (max 6 words)
If the user gives 8+ words, push back: "600×200 won't hold that legibly. Cut to the masthead + meta." Don't proceed until they agree.
3. Pick variation — ARCHITECTURE FIRST
Pick ONE. Newsletter headers favor restraint — pick the simplest archetype that carries the brand register:
chrome-led — masthead title + meta strip (issue / date). The classic newsletter header pattern; brand-earned for editorial titles.type-only — title alone at maximum scale; no meta at all.inverse-text — full canvas dark inversion (canonical v2 feature treatment) — masthead in cream on ink.object-of-content — looks like a printed masthead from a magazine/quarterly cover.
Then pick:
- Layout:
symmetric | asymmetric | full-bleed | split
- Color usage:
monochrome | single-accent | inverted
Cross-artifact rule: vary from the brand's most recent header (issue 002 vs issue 003 should not be visually identical).
4. Generate the canvas HTML
Template:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title><Brand> — Newsletter header — <issue></title>
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=<families>&display=swap">
<style>
<minimal subset of tokens.css needed for this artifact>
html, body { margin: 0; padding: 0; background: #2a2a2a; min-height: 100vh; display: grid; place-items: center; font-family: var(--type-sans-family); }
.canvas {
width: 600px;
height: 200px;
background: var(--color-surface);
color: var(--color-ink);
position: relative;
overflow: hidden;
padding: 24px 32px;
box-sizing: border-box;
display: flex;
flex-direction: column;
}
@page { size: 600px 200px; margin: 0; }
</style>
</head>
<body>
<article class="canvas">
</article>
</body>
</html>
For the masthead itself:
chrome-led: small mono dateline at top, masthead in display serif (~36-44px), tagline in small caps belowtype-only: the masthead title alone, scaled to fill the canvas (clamp 44-72px depending on word count)inverse-text: full canvas dark; same masthead pattern but inverted text colors
5. Verify and report
Newsletter header at ./design/<brand-slug>/artifacts/newsletter-header-YYYY-MM-DD-<slug>.html.
Variation: <archetype> × <layout> × <color>.
Export PNG: open in browser → DevTools → set viewport to 600×200 → screenshot the .canvas element. Embed the PNG as <img> in your email at full resolution (the email client renders the image directly, no font/CSS dependencies).
Anti-Slop Rules
Governed by three shared canonical references — read them, do not restate them:
../design-anti-patterns.md — the hard floor. Wins every conflict.../design-principles.md — the craft floor (typographic hierarchy, spatial rhythm, color theory, layout logic, visual tension).../design-variation-sop.md — the named-aesthetic roster + the procedure for varying every invocation.
Forbidden (fast scan — the references hold the full list):
- Indigo/violet/purple as default accent or primary — the
hsl(230–280) family on a near-white surface. The single loudest AI tell.
- Purple→blue / "aurora" / gradient-mesh backgrounds; gradient-fill text.
- Glassmorphism without an explicit AA-contrast scrim; floating gradient "blobs" as atmosphere.
- The three-up icon-card feature grid; the "hero → 3 cards → CTA" median skeleton.
- One global border-radius on every element; timid evenly-weighted low-contrast palette.
- Inter / Roboto / Arial / Open Sans / Lato / Helvetica / system as the primary family (Space Grotesk = yellow flag). Use a category-matched stack from the variation roster.
- Value-free CTAs ("Get Started", "Learn More", "Sign Up"); the two-CTA hero. Name the real action and its value.
Required variation (every invocation):
- Make at least two intentional decisions that differ from the safe defaults (palette, layout structure, typographic voice, or spatial density) AND from the most recent artifact in this brand.
- Never default to "clean / minimal / modern" — that is the absence of a direction (variation-sop Rule 1).
- Sketch three distinct directions, offer them as a one-line menu, generate the best-fit by default, all three only if asked (variation-sop Rule 3).
Authenticity: prefer specific over generic everywhere — real datelines (not "today"), the brand's actual voice (not "build the future" filler), concrete CTAs over placeholders.
Rules
- Pixel exactness. Canvas is 600×200 — the email-safe width. No rounding.
- Display scale ceiling. ~48px max. The canvas is small; oversized type breaks the proportions.
- Word count discipline. 6 words max for the masthead, 6 max for the tagline. Push back on the user if they exceed it.
- Token-pure. Every visual value via
var(--*) from the embedded tokens. Only literal pixel values allowed: 1px for hairlines and the canvas dimensions.
- One masthead per file. If the user wants alternates, make multiple files.
- Anti-pattern compliance. This skill defers to three shared canonical references:
../design-anti-patterns.md (the hard floor — wins every conflict), ../design-principles.md (the craft floor), and ../design-variation-sop.md (direction roster + offer-3 procedure). The anti-patterns file is the canonical anti-tell list. If you find a new tell in the output, add it there.
