diff --git a/src/components/debugger/CallStackPanel.tsx b/src/components/debugger/CallStackPanel.tsx
index 5b702af2..3febad18 100644
--- a/src/components/debugger/CallStackPanel.tsx
+++ b/src/components/debugger/CallStackPanel.tsx
@@ -143,6 +143,8 @@ export function CallStackPanel() {
   };
 
   const handleCopyStack = async () => {
+    // Guard: do not overwrite clipboard when there are no frames
+    if (frames().length === 0) return;
     const text = frames()
       .map((f) => {
         const loc = f.source?.path ? `${f.source.path}:${f.line}${f.column > 0 ? `:${f.column}` : ""}` : "unknown";
@@ -162,7 +164,7 @@ export function CallStackPanel() {
               <Icon name={showThreads() ? "eye" : "eye-slash"} size={12} />
             </IconButton>
           </Show>
-          <IconButton size="sm" variant="ghost" onClick={handleCopyStack} title="Copy Call Stack">
+          <IconButton size="sm" variant="ghost" onClick={handleCopyStack} disabled={frames().length === 0} title="Copy Call Stack">
             <Icon name="copy" size={12} />
           </IconButton>
         </div>