When a multi-line paste looks like code, a chip above the composer asks
"That looks like code. Format it as a code block (js)?" with Format as code /
No thanks. It never converts on its own; typing, No, or 8 s dismiss it, and
Settings → Editor → "Offer to Format Pasted Code" turns it off.
- utils/looksLikeCode.ts (pure, tested): ≥ 3 lines and ≥ 2 of indentation
with depth changes, statement terminators, operators + brackets, keywords,
monospace/<pre> clipboard HTML, or SQL clause lines. Prose guards: quoted
replies, URL lists, long sentence-punctuated lines, plain-word lines,
markdown lists. Language guess only when fairly sure (js/ts/python/sql/
rust/c/php).
- Accept rebuilds the pasted paragraphs as one code block from their plain
text (code lines hold text only) and leaves the caret after it.
- Code blocks carry an optional lang → <code class="language-js"> (whitelisted
identifier only).
Verified in Chromium: pasting a JS function shows the chip; Format as code →
sent formatted_body is <pre><code class="language-js"> with indentation intact;
a three-line prose paste shows no chip; typing after a paste dismisses it.
Unit tests: 14 detector fixtures + 2 output tests; chromium e2e 19 passed.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA
