diff --git a/services/code-server.nix b/services/code-server.nix
index b21249b..2ded3f1 100644
--- a/services/code-server.nix
+++ b/services/code-server.nix
@@ -33,14 +33,25 @@
     # Make the claude CLI available in code-server's integrated terminal.
     environment.systemPackages = [ pkgs.claude-code ];
 
-    # Patch the Claude Code extension to add crossorigin="anonymous" to its
-    # stylesheet link — required for Firefox due to stricter CORS handling.
-    # Idempotent: sed won't match after the first apply.
+    # Patch the Claude Code extension for Firefox compatibility.
+    # Idempotent: sed patterns won't match after first apply.
     system.activationScripts.claude-code-firefox-fix.text = ''
-      for f in /home/fred/.local/share/code-server/extensions/anthropic.claude-code-*/extension.js; do
-        [ -f "$f" ] && ${pkgs.gnused}/bin/sed -i \
-          's|<link href="''${q}" rel="stylesheet">|<link href="''${q}" rel="stylesheet" crossorigin="anonymous">|' \
-          "$f"
+      for d in /home/fred/.local/share/code-server/extensions/anthropic.claude-code-*/; do
+        [ -d "$d" ] || continue
+        # CORS fix: Firefox needs crossorigin on the stylesheet link.
+        ${pkgs.gnused}/bin/sed -i \
+          's|rel="stylesheet">|rel="stylesheet" crossorigin="anonymous">|g' \
+          "$d/extension.js"
+        # Firefox contentEditable="plaintext-only" doesn't visually render
+        # newlines on Shift+Enter. Two fixes:
+        # 1. Intercept Shift+Enter to explicitly insert a line break.
+        ${pkgs.gnused}/bin/sed -i \
+          's|if(d.key==="Enter"&&!d.shiftKey)|if(d.key==="Enter"\&\&d.shiftKey){d.preventDefault();document.execCommand("insertLineBreak");T7();return}if(d.key==="Enter"\&\&!d.shiftKey)|' \
+          "$d/webview/index.js"
+        # 2. Read innerText (converts <br> to \n) instead of textContent (ignores <br>).
+        ${pkgs.gnused}/bin/sed -i \
+          's|t\.current?.textContent|t.current?.innerText|g' \
+          "$d/webview/index.js"
       done
     '';
   };