Fix: disguised-ad-flag skips single card with content wrapper (#228 follow-up)

[twschiller]

Summary

Follow-up to #230 (review feedback from Unblocked bot).

PR #230's hasOtherCardSubtree guard rejected any candidate enclosing a descendant outside the label's chain that carried both an image and an outgoing link. A common card layout — label as a sibling to a single content wrapper that holds heading + image + link — tripped the guard, and the legitimate ad card escaped detection entirely.

<article>
  <span class="label">Sponsored</span>
  <div class="card-body">
    <h2><a href="/ad">Title</a></h2>
    <img src="ad.jpg" />
    <p>Long body text…</p>
  </div>
</article>

div.card-body is not the label, not contained by the label, and does not contain the label. It has both an <img> and an <a href> descendant → the pre-fix guard returned true → isArticleShaped returned false → the card was not hidden.

Fix

Rename hasOtherCardSubtree → hasMultipleCardSubtrees and require two or more outermost non-overlapping qualifying subtrees before rejecting. The label's own containing chain does count toward the total (the candidate.contains(labelElement) skip is dropped), so a feed wrapper still trips at >= 2 (label's card + sibling cards), while a single card with one (or several stacked) content wrappers collapses to 1.

Verifying #228 still holds

• Reddit <shreddit-feed> with 3 ad-post cards, one momentarily headless: walking from the headless card's label reaches the feed; the feed encloses 3 outermost card subtrees (each card has img+a) → count >= 2 → feed wrapper is rejected, individual headed cards still match on their own walk-up.
• 2-card feed with one headless: 2 outermost card subtrees → count = 2 → feed rejected.

Test plan

• bun run check — clean
• bun run typecheck — clean
• bun run knip — clean
• ./node_modules/.bin/jest — 1918 tests passing, including:
  • new hides a single card whose content sits inside a wrapper div regression test in disguised-ad-flag.test.ts
  • new fast-check property in disguised-ad-flag.property.test.ts asserting that a single card with N stacked wrapper divs is always hidden (N ∈ [1, 5])
• Manual on reddit.com with the unpacked extension after merge

🤖 Generated with Claude Code

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
agent-browser-shield-demo-site	Ready	Preview, Comment	Jun 9, 2026 2:41pm