diff --git a/package.json b/package.json
index 0efc775e..f17cfdab 100644
--- a/package.json
+++ b/package.json
@@ -80,6 +80,7 @@
     "radix-ui": "^1.4.3",
     "react-markdown": "^10.1.0",
     "rehype-highlight": "^7.0.2",
+    "remark-breaks": "^4.0.0",
     "remark-frontmatter": "^5.0.0",
     "remark-gfm": "^4.0.1",
     "shadcn": "^4.1.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 01cf0521..5efda2ed 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -136,6 +136,9 @@ importers:
       rehype-highlight:
         specifier: ^7.0.2
         version: 7.0.2
+      remark-breaks:
+        specifier: ^4.0.0
+        version: 4.0.0
       remark-frontmatter:
         specifier: ^5.0.0
         version: 5.0.0
@@ -4370,6 +4373,9 @@ packages:
   mdast-util-mdxjs-esm@2.0.1:
     resolution: {integrity: sha512-EcmOpxsZ96CvlP03NghtH1EsLtr0n9Tm4lPUJUBccV9RwUOneqSycg19n5HGzCf+10LozMRSObtVr3ee1WoHtg==}
 
+  mdast-util-newline-to-break@2.0.0:
+    resolution: {integrity: sha512-MbgeFca0hLYIEx/2zGsszCSEJJ1JSCdiY5xQxRcLDDGa8EPvlLPupJ4DSajbMPAnC0je8jfb9TiUATnxxrHUog==}
+
   mdast-util-phrasing@4.1.0:
     resolution: {integrity: sha512-TqICwyvJJpBwvGAMZjj4J2n0X8QWp21b9l0o7eXyVJ25YNWYbJDVIyD1bZXE6WtV6RmKJVYmQAKWa0zWOABz2w==}
 
@@ -5058,6 +5064,9 @@ packages:
   rehype-highlight@7.0.2:
     resolution: {integrity: sha512-k158pK7wdC2qL3M5NcZROZ2tR/l7zOzjxXd5VGdcfIyoijjQqpHd3JKtYSBDpDZ38UI2WJWuFAtkMDxmx5kstA==}
 
+  remark-breaks@4.0.0:
+    resolution: {integrity: sha512-IjEjJOkH4FuJvHZVIW0QCDWxcG96kCq7An/KVH2NfJe6rKZU2AsHeB3OEjPNRxi4QC34Xdx7I2KGYn6IpT7gxQ==}
+
   remark-frontmatter@5.0.0:
     resolution: {integrity: sha512-XTFYvNASMe5iPN0719nPrdItC9aU0ssC4v14mH1BCi1u0n1gAocqcujWUrByftZTbLhRtiKRyjYTSIOcr69UVQ==}
 
@@ -10141,6 +10150,11 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
+  mdast-util-newline-to-break@2.0.0:
+    dependencies:
+      '@types/mdast': 4.0.4
+      mdast-util-find-and-replace: 3.0.2
+
   mdast-util-phrasing@4.1.0:
     dependencies:
       '@types/mdast': 4.0.4
@@ -11124,6 +11138,12 @@ snapshots:
       unist-util-visit: 5.1.0
       vfile: 6.0.3
 
+  remark-breaks@4.0.0:
+    dependencies:
+      '@types/mdast': 4.0.4
+      mdast-util-newline-to-break: 2.0.0
+      unified: 11.0.5
+
   remark-frontmatter@5.0.0:
     dependencies:
       '@types/mdast': 4.0.4
diff --git a/src/renderer/src/components/sidebar/CommentMarkdown.tsx b/src/renderer/src/components/sidebar/CommentMarkdown.tsx
new file mode 100644
index 00000000..aa051567
--- /dev/null
+++ b/src/renderer/src/components/sidebar/CommentMarkdown.tsx
@@ -0,0 +1,132 @@
+import React from 'react'
+import Markdown from 'react-markdown'
+import remarkGfm from 'remark-gfm'
+import remarkBreaks from 'remark-breaks'
+import type { Components } from 'react-markdown'
+import { cn } from '@/lib/utils'
+
+// Why: sidebar comments are rendered at 11px in a narrow card, so we strip
+// block-level wrappers that add unwanted margins and only keep inline
+// formatting (bold, italic, code, links) plus compact lists and line breaks.
+// Using react-markdown (already a project dependency) lets AI agents write
+// markdown via `orca worktree set --comment` and have it render nicely.
+
+const components: Components = {
+  // Strip <p> wrappers to avoid double margins in the tight card layout.
+  p: ({ children }) => <span className="comment-md-p">{children}</span>,
+  // Open links externally — sidebar is not a navigation context.
+  a: ({ href, children }) => (
+    <a
+      href={href}
+      target="_blank"
+      rel="noreferrer"
+      className="underline underline-offset-2 text-foreground/80 hover:text-foreground"
+      onClick={(e) => e.stopPropagation()}
+    >
+      {children}
+    </a>
+  ),
+  // Why: react-markdown calls the `code` component for both inline `code`
+  // and the <code> inside fenced blocks (<pre><code>…</code></pre>). We
+  // always apply inline-code styling here; the wrapper div uses a CSS
+  // descendant selector ([&_pre_code]) at higher specificity to strip
+  // the pill background/padding when code is inside a <pre>. This is
+  // more reliable than checking `className` — which is only set when
+  // the fenced block specifies a language (```js), not for bare ```.
+  code: ({ children }) => (
+    <code className="rounded bg-accent px-1 py-px text-[10px] font-mono">{children}</code>
+  ),
+  // Compact pre blocks — no syntax highlighting needed for short comments
+  pre: ({ children }) => (
+    <pre className="my-1 rounded bg-accent p-1.5 text-[10px] font-mono overflow-x-auto max-h-32">
+      {children}
+    </pre>
+  ),
+  // Compact lists
+  ul: ({ children }) => <ul className="my-0.5 ml-3 list-disc space-y-0">{children}</ul>,
+  ol: ({ children }) => <ol className="my-0.5 ml-3 list-decimal space-y-0">{children}</ol>,
+  // Why: GFM task list checkboxes are non-functional in a read-only comment
+  // card (clicking them would just open the edit modal via the parent's
+  // onClick). Rendering them disabled avoids a misleading interactive
+  // affordance.
+  li: ({ children }) => (
+    <li className="leading-normal [&>input]:pointer-events-none">{children}</li>
+  ),
+  // Headings render as bold text at the same size — no visual hierarchy needed
+  // in a tiny sidebar card.
+  h1: ({ children }) => <span className="font-bold">{children}</span>,
+  h2: ({ children }) => <span className="font-bold">{children}</span>,
+  h3: ({ children }) => <span className="font-semibold">{children}</span>,
+  h4: ({ children }) => <span className="font-semibold">{children}</span>,
+  h5: ({ children }) => <span className="font-semibold">{children}</span>,
+  h6: ({ children }) => <span className="font-semibold">{children}</span>,
+  // Horizontal rules as a subtle divider
+  hr: () => <hr className="my-1 border-border/50" />,
+  // Compact blockquotes
+  blockquote: ({ children }) => (
+    <blockquote className="my-0.5 border-l-2 border-border/60 pl-2 text-muted-foreground/80">
+      {children}
+    </blockquote>
+  ),
+  // Why: images in a ~200px sidebar card would blow out the layout or look
+  // broken at any reasonable size. Render as a text link instead so the URL is
+  // still accessible without disrupting the card.
+  img: ({ alt, src }) => (
+    <a
+      href={src}
+      target="_blank"
+      rel="noreferrer"
+      className="underline underline-offset-2 text-foreground/80 hover:text-foreground"
+      onClick={(e) => e.stopPropagation()}
+    >
+      {alt || 'image'}
+    </a>
+  ),
+  // Why: GFM tables in a ~200px sidebar would overflow badly. Wrapping in an
+  // overflow container keeps the card layout stable while still letting the
+  // user scroll to see the full table.
+  table: ({ children }) => (
+    <div className="my-1 overflow-x-auto">
+      <table className="text-[10px] border-collapse [&_td]:border [&_td]:border-border/40 [&_td]:px-1 [&_td]:py-0.5 [&_th]:border [&_th]:border-border/40 [&_th]:px-1 [&_th]:py-0.5 [&_th]:font-semibold [&_th]:text-left">
+        {children}
+      </table>
+    </div>
+  )
+}
+
+// Why: standard CommonMark collapses single newlines into spaces. The old
+// plain-text renderer used whitespace-pre-wrap which preserved them. Adding
+// remark-breaks converts single newlines to <br>, keeping backward compat
+// with existing plain-text comments that rely on newline formatting.
+const remarkPlugins = [remarkGfm, remarkBreaks]
+
+type CommentMarkdownProps = {
+  content: string
+  className?: string
+  onClick?: (e: React.MouseEvent) => void
+}
+
+const CommentMarkdown = React.memo(function CommentMarkdown({
+  content,
+  className,
+  onClick
+}: CommentMarkdownProps) {
+  return (
+    <div
+      className={cn(
+        // Reset inline-code pill styles when <code> is inside a <pre> block.
+        // The descendant selector (pre code) has higher specificity than the
+        // direct utility classes on <code>, so these overrides win reliably.
+        '[&_pre_code]:bg-transparent [&_pre_code]:p-0 [&_pre_code]:rounded-none',
+        className
+      )}
+      onClick={onClick}
+    >
+      <Markdown remarkPlugins={remarkPlugins} components={components}>
+        {content}
+      </Markdown>
+    </div>
+  )
+})
+
+export default CommentMarkdown
diff --git a/src/renderer/src/components/sidebar/WorktreeCard.tsx b/src/renderer/src/components/sidebar/WorktreeCard.tsx
index 3223d142..6b7f42bb 100644
--- a/src/renderer/src/components/sidebar/WorktreeCard.tsx
+++ b/src/renderer/src/components/sidebar/WorktreeCard.tsx
@@ -7,6 +7,7 @@ import { Tooltip, TooltipTrigger, TooltipContent } from '@/components/ui/tooltip
 import { Bell, GitMerge, LoaderCircle, CircleDot, CircleCheck, CircleX } from 'lucide-react'
 import StatusIndicator from './StatusIndicator'
 import CacheTimer from './CacheTimer'
+import CommentMarkdown from './CommentMarkdown'
 import WorktreeContextMenu from './WorktreeContextMenu'
 import { cn } from '@/lib/utils'
 import { detectAgentStatusFromTitle } from '@/lib/agent-status'
@@ -558,12 +559,11 @@ const WorktreeCard = React.memo(function WorktreeCard({
               )}
 
               {cardProps.includes('comment') && worktree.comment && (
-                <div
-                  className="text-[11px] text-muted-foreground whitespace-pre-wrap break-words cursor-pointer -mx-1.5 px-1.5 py-0.5 hover:bg-background/40 hover:text-foreground rounded transition-colors leading-normal"
+                <CommentMarkdown
+                  content={worktree.comment}
+                  className="text-[11px] text-muted-foreground break-words cursor-pointer -mx-1.5 px-1.5 py-0.5 hover:bg-background/40 hover:text-foreground rounded transition-colors leading-normal [&_.comment-md-p]:block [&_.comment-md-p+.comment-md-p]:mt-1"
                   onClick={handleEditComment}
-                >
-                  {worktree.comment}
-                </div>
+                />
               )}
             </div>
           )}
diff --git a/src/renderer/src/components/sidebar/WorktreeMetaDialog.tsx b/src/renderer/src/components/sidebar/WorktreeMetaDialog.tsx
index 52dcbdc6..43f673a9 100644
--- a/src/renderer/src/components/sidebar/WorktreeMetaDialog.tsx
+++ b/src/renderer/src/components/sidebar/WorktreeMetaDialog.tsx
@@ -203,7 +203,8 @@ const WorktreeMetaDialog = React.memo(function WorktreeMetaDialog() {
               className="w-full min-w-0 rounded-md border border-input bg-transparent px-3 py-2 text-xs shadow-xs transition-[color,box-shadow] outline-none placeholder:text-muted-foreground focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50 resize-none max-h-60 overflow-y-auto"
             />
             <p className="text-[10px] text-muted-foreground">
-              Press Enter or {isMac ? 'Cmd' : 'Ctrl'}+Enter to save, Shift+Enter for a new line.
+              Supports **markdown** — bold, lists, `code`, links. Press Enter or{' '}
+              {isMac ? 'Cmd' : 'Ctrl'}+Enter to save, Shift+Enter for a new line.
             </p>
           </div>
         </div>
diff --git a/src/renderer/src/components/sidebar/worktree-list-estimate.ts b/src/renderer/src/components/sidebar/worktree-list-estimate.ts
index b4fb7574..13338b1b 100644
--- a/src/renderer/src/components/sidebar/worktree-list-estimate.ts
+++ b/src/renderer/src/components/sidebar/worktree-list-estimate.ts
@@ -48,16 +48,48 @@ export function estimateRowHeight(
     }
   }
   if (cardProps.includes('comment') && wt.comment) {
-    // Comment renders with whitespace-pre-wrap + break-words, so its height
-    // depends on content.  Estimate visual lines from explicit newlines and
-    // character wrapping (~35 chars per line at typical sidebar width).
+    // Comment renders as markdown via react-markdown. Markdown block elements
+    // (lists, code blocks, blockquotes) add some vertical overhead compared to
+    // raw text, but the dominant factor is still line count. We estimate visual
+    // lines from explicit newlines and character wrapping (~35 chars per line at
+    // typical sidebar width), then add a small buffer for markdown block spacing.
     // Line-height is leading-normal (1.5 × 11px = 16.5px) + py-0.5(4px).
     const lines = wt.comment.split('\n')
     let totalLines = 0
+    let hasBlocks = false
+    let inCodeFence = false
+    let codeFenceLines = 0
     for (const line of lines) {
-      totalLines += Math.max(1, Math.ceil(line.length / 35))
+      if (line.startsWith('```')) {
+        hasBlocks = true
+        if (inCodeFence) {
+          // Closing fence: cap at max-h-32 (128px) ÷ 16.5 ≈ 8 visible lines
+          totalLines += Math.min(codeFenceLines, 8)
+          codeFenceLines = 0
+        }
+        inCodeFence = !inCodeFence
+        continue
+      }
+      if (inCodeFence) {
+        codeFenceLines++
+      } else {
+        totalLines += Math.max(1, Math.ceil(line.length / 35))
+        // Detect markdown block elements that add extra vertical spacing.
+        // Only check outside code fences — fenced content renders as plain code.
+        if (/^(\s*[-*+]\s|#{1,6}\s|>\s|---|\d+\.\s)/.test(line)) {
+          hasBlocks = true
+        }
+      }
+    }
+    // Handle unclosed code fence (treat remaining lines normally)
+    if (inCodeFence) {
+      totalLines += Math.min(codeFenceLines, 8)
     }
     h += Math.ceil(totalLines * 16.5) + 4
+    // Markdown blocks (lists, headings, code fences) add ~4-8px of extra margin
+    if (hasBlocks) {
+      h += 8
+    }
     metaCount++
   }