Render markdown in comments.

README.md

@@ -752,6 +752,27 @@ author starts as a draft. An agent has no drafting step — it posts a review it
 has already decided on — so `"author":"claude"` is born submitted: an open thread,
 with no **Submit review** click standing between it and being read.
 
+### Comments are markdown
+
+A comment body is markdown, rendered where it is read: fenced code (highlighted
+by the same theme as the diff beside it), `inline code`, bold, italic,
+strikethrough, links, bare URLs, nested and numbered lists with `- [ ]` task
+items, headings, quotes and rules. Soft line breaks are hard breaks, as they are
+in a GitHub comment box — comments are typed in lines, not in paragraphs.
+
+It matters most for the comments you did not type. An agent writes the way it
+writes — a claim, a fenced snippet of the fix, a link — and before this that
+arrived as a wall of asterisks and backticks. Nothing about the stored comment
+changed: the body is still plain text, in `reviews.json`, and the editor still
+edits the text you wrote. Tables and reference links are not rendered; they show
+as the text they were typed as. The renderer is `web/src/lib/markdown.tsx`, five hundred
+lines and no dependency — the pane already owns a syntax
+highlighter, and the shapes a review comment actually uses are a short list.
+
+The rail's cards and a collapsed thread's one-line preview strip the markup
+instead of rendering it: three clamped lines have no room for a code block, and
+raw `**syntax**` reads worse than none.
+
 ### The two skills
 
 `mise run install-skills` installs them into `~/.claude/skills`, keeping whatever