diff --git a/public/css/sub-pages.css b/public/css/sub-pages.css
index ac5019c65..e0fd0e030 100644
--- a/public/css/sub-pages.css
+++ b/public/css/sub-pages.css
@@ -570,6 +570,217 @@ main#main {
   background: var(--color-cream);
 }
 
+/* ============================================
+   ANTI-PATTERNS INDEX
+   ============================================ */
+
+.anti-patterns-sidebar-list a {
+  display: flex !important;
+  align-items: baseline;
+  justify-content: space-between;
+  gap: var(--spacing-sm);
+}
+
+.anti-patterns-sidebar-count {
+  font-size: 0.6875rem;
+  font-weight: 500;
+  color: var(--color-ash);
+  font-variant-numeric: tabular-nums;
+}
+
+.anti-patterns-content {
+  max-width: 820px;
+}
+
+.anti-patterns-header {
+  margin-bottom: clamp(2.5rem, 5vw, 4rem);
+}
+
+.anti-patterns-header .sub-page-lede code {
+  font-family: var(--font-mono);
+  font-size: 0.875em;
+  color: var(--color-ink);
+  background: var(--color-cream);
+  padding: 2px 6px;
+  border-radius: 4px;
+  border: 1px solid var(--color-mist);
+}
+
+.anti-patterns-header .sub-page-lede a {
+  color: var(--color-ink);
+  text-decoration: underline;
+  text-decoration-color: var(--color-accent);
+  text-decoration-thickness: 1px;
+  text-underline-offset: 4px;
+  font-family: var(--font-mono);
+  font-weight: 500;
+  font-size: 0.9375em;
+}
+
+.anti-patterns-legend {
+  padding: var(--spacing-lg);
+  background: var(--color-cream);
+  border: 1px solid var(--color-mist);
+  border-radius: 10px;
+  margin-bottom: clamp(2.5rem, 5vw, 4rem);
+  max-width: 720px;
+}
+
+.anti-patterns-legend-title {
+  font-family: var(--font-display);
+  font-size: 1.25rem;
+  font-style: italic;
+  font-weight: 500;
+  color: var(--color-ink);
+  margin-bottom: var(--spacing-sm);
+}
+
+.anti-patterns-legend p {
+  font-size: 0.9375rem;
+  line-height: 1.7;
+  color: var(--color-charcoal);
+}
+
+.anti-patterns-legend a {
+  color: var(--color-ink);
+  text-decoration: none;
+  border-bottom: 1px solid var(--color-accent);
+  font-family: var(--font-mono);
+  font-size: 0.875em;
+  font-weight: 500;
+}
+
+.anti-patterns-legend a:hover {
+  color: var(--color-accent);
+}
+
+.anti-patterns-sections {
+  display: flex;
+  flex-direction: column;
+  gap: clamp(3rem, 6vw, 4.5rem);
+}
+
+.anti-patterns-section-header {
+  display: flex;
+  align-items: baseline;
+  justify-content: space-between;
+  gap: var(--spacing-md);
+  padding-bottom: var(--spacing-sm);
+  border-bottom: 1px solid var(--color-mist);
+  margin-bottom: var(--spacing-lg);
+}
+
+.anti-patterns-section-title {
+  font-family: var(--font-display);
+  font-size: clamp(1.75rem, 3vw, 2.25rem);
+  font-weight: 500;
+  font-style: italic;
+  color: var(--color-ink);
+  letter-spacing: -0.01em;
+}
+
+.anti-patterns-section-count {
+  font-family: var(--font-mono);
+  font-size: 0.6875rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.12em;
+  color: var(--color-ash);
+}
+
+.rule-card-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
+  gap: var(--spacing-md);
+}
+
+.rule-card {
+  padding: var(--spacing-md);
+  background: var(--color-paper);
+  border: 1px solid var(--color-mist);
+  border-radius: 8px;
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+  transition: border-color var(--duration-fast) var(--ease-out);
+}
+
+.rule-card:hover {
+  border-color: var(--color-ash);
+}
+
+.rule-card-head {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--spacing-sm);
+  margin-bottom: 2px;
+}
+
+.rule-card-id {
+  font-family: var(--font-mono);
+  font-size: 0.75rem;
+  font-weight: 500;
+  color: var(--color-ash);
+  background: transparent;
+  padding: 0;
+  border: none;
+}
+
+.rule-card-category {
+  font-family: var(--font-mono);
+  font-size: 0.625rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.1em;
+  padding: 3px 8px;
+  border-radius: 99px;
+}
+
+.rule-card-category[data-category="slop"] {
+  color: var(--color-accent);
+  background: var(--color-accent-dim);
+}
+
+.rule-card-category[data-category="quality"] {
+  color: var(--color-charcoal);
+  background: var(--color-mist);
+}
+
+.rule-card-name {
+  font-family: var(--font-body);
+  font-size: 1rem;
+  font-weight: 600;
+  color: var(--color-ink);
+  line-height: 1.35;
+}
+
+.rule-card-desc {
+  font-size: 0.875rem;
+  line-height: 1.6;
+  color: var(--color-charcoal);
+  flex: 1;
+}
+
+.rule-card-skill-link {
+  font-family: var(--font-mono);
+  font-size: 0.75rem;
+  font-weight: 500;
+  color: var(--color-charcoal);
+  text-decoration: none;
+  align-self: flex-start;
+  padding-top: 4px;
+  transition: color var(--duration-fast) var(--ease-out);
+}
+
+.rule-card-skill-link:hover {
+  color: var(--color-accent);
+}
+
+.rule-card-skill-link::after {
+  content: " →";
+}
+
 /* ============================================
    MOBILE: collapse sidebar into inline block
    ============================================ */
diff --git a/scripts/build-sub-pages.js b/scripts/build-sub-pages.js
index 5111b5eb0..4a937036c 100644
--- a/scripts/build-sub-pages.js
+++ b/scripts/build-sub-pages.js
@@ -212,6 +212,124 @@ ${mainHtml}
 </div>`;
 }
 
+/**
+ * Group anti-pattern rules by skill section.
+ * Rules without a skillSection fall into a 'General quality' bucket.
+ */
+function groupRulesBySection(rules) {
+  const order = [
+    'Visual Details',
+    'Typography',
+    'Color & Contrast',
+    'Layout & Space',
+    'Motion',
+    'General quality',
+  ];
+  const bySection = {};
+  for (const name of order) bySection[name] = [];
+  for (const rule of rules) {
+    const section = rule.skillSection || 'General quality';
+    if (!bySection[section]) bySection[section] = [];
+    bySection[section].push(rule);
+  }
+  // Sort each bucket: slop first (they're the named tells), then quality.
+  for (const name of Object.keys(bySection)) {
+    bySection[name].sort((a, b) => {
+      if (a.category !== b.category) return a.category === 'slop' ? -1 : 1;
+      return a.name.localeCompare(b.name);
+    });
+  }
+  return { order, bySection };
+}
+
+/**
+ * Render the anti-patterns sidebar: a table of contents of rule sections
+ * with per-section rule counts. Every entry anchor-jumps to the section
+ * in the main column.
+ */
+function renderAntiPatternsSidebar(grouped) {
+  const entries = grouped.order
+    .filter((section) => grouped.bySection[section]?.length > 0)
+    .map((section) => {
+      const slug = slugify(section);
+      const count = grouped.bySection[section].length;
+      return `        <li><a href="#section-${slug}"><span>${escapeHtml(section)}</span><span class="anti-patterns-sidebar-count">${count}</span></a></li>`;
+    })
+    .join('\n');
+
+  return `
+<aside class="skills-sidebar anti-patterns-sidebar" aria-label="Anti-pattern sections">
+  <div class="skills-sidebar-inner">
+    <p class="skills-sidebar-label">Sections</p>
+    <div class="skills-sidebar-group">
+      <ul class="skills-sidebar-list anti-patterns-sidebar-list">
+${entries}
+      </ul>
+    </div>
+  </div>
+</aside>`;
+}
+
+/**
+ * Render one rule card inside the anti-patterns main column.
+ */
+function renderRuleCard(rule) {
+  const categoryLabel = rule.category === 'slop' ? 'AI slop' : 'Quality';
+  const skillLink = rule.skillSection
+    ? `<a class="rule-card-skill-link" href="/skills/impeccable#${slugify(rule.skillSection)}">See in /impeccable</a>`
+    : '';
+  return `
+    <article class="rule-card" id="rule-${rule.id}">
+      <div class="rule-card-head">
+        <code class="rule-card-id">${escapeHtml(rule.id)}</code>
+        <span class="rule-card-category" data-category="${rule.category}">${categoryLabel}</span>
+      </div>
+      <h3 class="rule-card-name">${escapeHtml(rule.name)}</h3>
+      <p class="rule-card-desc">${escapeHtml(rule.description)}</p>
+      ${skillLink}
+    </article>`;
+}
+
+/**
+ * Render the /anti-patterns main column content.
+ */
+function renderAntiPatternsMain(grouped, totalRules) {
+  let sectionsHtml = '';
+  for (const section of grouped.order) {
+    const rules = grouped.bySection[section] || [];
+    if (rules.length === 0) continue;
+    const slug = slugify(section);
+    sectionsHtml += `
+    <section class="anti-patterns-section" id="section-${slug}">
+      <header class="anti-patterns-section-header">
+        <h2 class="anti-patterns-section-title">${escapeHtml(section)}</h2>
+        <p class="anti-patterns-section-count">${rules.length} ${rules.length === 1 ? 'rule' : 'rules'}</p>
+      </header>
+      <div class="rule-card-grid">
+${rules.map(renderRuleCard).join('\n')}
+      </div>
+    </section>`;
+  }
+
+  return `
+<div class="anti-patterns-content">
+  <header class="anti-patterns-header">
+    <p class="sub-page-eyebrow">${totalRules} detection rules</p>
+    <h1 class="sub-page-title">Anti-patterns</h1>
+    <p class="sub-page-lede">These are the visible tells of AI-generated interfaces. Every rule in this catalog is implemented as a deterministic check in <code>npx impeccable detect</code> and in the browser extension. Run <a href="/skills/critique">/critique</a> on any page to see which ones it triggers.</p>
+  </header>
+
+  <section class="anti-patterns-legend">
+    <h2 class="anti-patterns-legend-title">How to read this</h2>
+    <p>Rules are grouped by the section of the <a href="/skills/impeccable">/impeccable</a> skill that teaches the pattern to avoid. <strong>AI slop</strong> rules flag the specific visual tells (gradient text, purple palettes, side-tab borders, nested cards). <strong>Quality</strong> rules flag general design mistakes that are not AI-specific but still hurt the work.</p>
+  </section>
+
+  <div class="anti-patterns-sections">
+${sectionsHtml}
+  </div>
+</div>`;
+}
+
 /**
  * Entry point. Generates all sub-page HTML files.
  *
@@ -271,5 +389,23 @@ export async function generateSubPages(rootDir) {
     generated.push(out);
   }
 
+  // Anti-patterns index: single page, docs-browser shell with TOC sidebar.
+  {
+    const grouped = groupRulesBySection(data.rules);
+    const sidebar = renderAntiPatternsSidebar(grouped);
+    const main = renderAntiPatternsMain(grouped, data.rules.length);
+    const html = renderPage({
+      title: 'Anti-patterns | Impeccable',
+      description: `${data.rules.length} deterministic detection rules that flag the visible tells of AI-generated interfaces and common quality issues. Used by npx impeccable detect and the browser extension.`,
+      bodyHtml: wrapInDocsLayout(sidebar, main),
+      activeNav: 'anti-patterns',
+      canonicalPath: '/anti-patterns',
+      bodyClass: 'sub-page skills-layout-page anti-patterns-page',
+    });
+    const out = path.join(outDirs.antiPatterns, 'index.html');
+    fs.writeFileSync(out, html, 'utf-8');
+    generated.push(out);
+  }
+
   return { files: generated };
 }