Detect tmux version, warn about 3.4 key handling issues

- API returns tmux version alongside sessions
- Show yellow warning banner for tmux 3.4.x with fix instructions
- Suggest upgrade to 3.5+ or set extended-keys off

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: davindicode

app/components/terminal/InputBox.tsx

@@ -165,6 +165,7 @@ export default function InputBox() {
   const [text, setText] = useState("");
   const [activeGroup, setActiveGroup] = useState<string | null>(null);
   const [tmuxSessions, setTmuxSessions] = useState<TmuxSession[]>([]);
+  const [tmuxVersion, setTmuxVersion] = useState<string | null>(null);
   const [tmuxLoading, setTmuxLoading] = useState(false);
   const [tmuxNewName, setTmuxNewName] = useState("");
   const [editorFileName, setEditorFileName] = useState("");
@@ -275,6 +276,7 @@ export default function InputBox() {
       const res = await fetch("/api/tmux/sessions");
       const data = await res.json();
       setTmuxSessions(data.sessions || []);
+      if (data.version) setTmuxVersion(data.version);
     } catch { setTmuxSessions([]); }
     setTmuxLoading(false);
   };
@@ -628,6 +630,11 @@ export default function InputBox() {
       )}
       {activeGroup === TMUX_TAB && !inTmux && (
         <div className="border-b border-gray-700/50 bg-[#12122a] px-3 py-2">
+          {tmuxVersion && tmuxVersion.startsWith("3.4") && (
+            <div className="text-[10px] text-yellow-400 bg-yellow-900/20 border border-yellow-800/30 rounded px-2 py-1 mb-1.5">
+              tmux {tmuxVersion} has known key handling issues. Upgrade to 3.5+ or add <code className="text-yellow-300">set -g extended-keys off</code> to ~/.tmux.conf
+            </div>
+          )}
           {tmuxLoading ? (
             <span className="text-[11px] text-gray-500">Loading...</span>
           ) : tmuxSessions.length === 0 ? (

app/routes/api/tmux.sessions.ts

@@ -1,25 +1,36 @@
 import { execSync } from "child_process";
 import type { Route } from "./+types/tmux.sessions";
 
+function getTmuxVersion(): string | null {
+  try {
+    const output = execSync("tmux -V", { encoding: "utf-8", timeout: 3000 }).trim();
+    // "tmux 3.4" or "tmux 3.5a"
+    return output.replace(/^tmux\s+/, "");
+  } catch {
+    return null;
+  }
+}
+
 export async function loader({ request }: Route.LoaderArgs) {
+  const version = getTmuxVersion();
+
   try {
     const output = execSync("tmux list-sessions -F '#{session_name}:#{session_windows}:#{session_attached}'", {
       encoding: "utf-8",
       timeout: 3000,
     }).trim();
 
     if (!output) {
-      return Response.json({ sessions: [] });
+      return Response.json({ sessions: [], version });
     }
 
     const sessions = output.split("\n").map((line) => {
       const [name, windows, attached] = line.split(":");
       return { name, windows: parseInt(windows, 10), attached: attached === "1" };
     });
 
-    return Response.json({ sessions });
+    return Response.json({ sessions, version });
   } catch {
-    // tmux not running or not installed
-    return Response.json({ sessions: [] });
+    return Response.json({ sessions: [], version });
   }
 }