diff --git a/mac/VibeTunnel/vt b/mac/VibeTunnel/vt
index 4683dd3e..74ff2db0 100755
--- a/mac/VibeTunnel/vt
+++ b/mac/VibeTunnel/vt
@@ -1,6 +1,13 @@
 #!/bin/bash
 # VibeTunnel CLI wrapper
 
+# Check if we're already inside a VibeTunnel session
+if [ -n "$VIBETUNNEL_SESSION_ID" ]; then
+    echo "Error: Already inside a VibeTunnel session (ID: $VIBETUNNEL_SESSION_ID). Recursive VibeTunnel sessions are not supported." >&2
+    echo "If you need to run commands, use them directly without the 'vt' prefix." >&2
+    exit 1
+fi
+
 # Try standard locations first, but verify the binary exists
 APP_PATH=""
 for TRY_PATH in "/Applications/VibeTunnel.app" "$HOME/Applications/VibeTunnel.app"; do
diff --git a/web/src/server/pty/pty-manager.ts b/web/src/server/pty/pty-manager.ts
index 36d1e2c6..a24ae9e1 100644
--- a/web/src/server/pty/pty-manager.ts
+++ b/web/src/server/pty/pty-manager.ts
@@ -237,6 +237,8 @@ export class PtyManager extends EventEmitter {
         const ptyEnv = {
           ...process.env,
           TERM: term,
+          // Set session ID to prevent recursive vt calls and for debugging
+          VIBETUNNEL_SESSION_ID: sessionId,
         };
 
         // Debug log the spawn parameters