diff --git a/src/chatdbg/chatdbg_gdb.py b/src/chatdbg/chatdbg_gdb.py
index 485afe2..6d64d28 100644
--- a/src/chatdbg/chatdbg_gdb.py
+++ b/src/chatdbg/chatdbg_gdb.py
@@ -88,7 +88,7 @@ def invoke(self, arg, from_tty, really_run=True):
 Why()
 
 
-def buildPrompt() -> str:
+def buildPrompt() -> tuple[str, str, str]:
     thread = gdb.selected_thread()
     if not thread:
         return ""
diff --git a/src/chatdbg/chatdbg_lldb.py b/src/chatdbg/chatdbg_lldb.py
index 4d2f567..f26a822 100644
--- a/src/chatdbg/chatdbg_lldb.py
+++ b/src/chatdbg/chatdbg_lldb.py
@@ -117,16 +117,14 @@ def truncate_string(string, n):
 
 
 def buildPrompt(debugger: Any) -> Tuple[str, str, str]:
-    import os
-
     target = get_target()
     if not target:
-        return ""
+        return ("", "", "")
     thread = get_thread()
     if not thread:
-        return ""
+        return ("", "", "")
     if thread.GetStopReason() == lldb.eStopReasonBreakpoint:
-        return ""
+        return ("", "", "")
     frame = thread.GetFrameAtIndex(0)
     stack_trace = ""
     source_code = ""