fix(code-exec): preserve interrupt cancellation source

tools/code_execution_tool.py

@@ -1060,6 +1060,19 @@ def _rpc_poll_loop(
             stop_event.wait(poll_interval)
 
 
+def _format_interrupted_output(stdout_text: str) -> str:
+    """Append an interruption marker without guessing who caused it."""
+    from tools.interrupt import get_interrupt_reason
+
+    reason = get_interrupt_reason()
+    marker = (
+        f"[execution interrupted — {reason}]"
+        if reason
+        else "[execution interrupted]"
+    )
+    return f"{stdout_text}\n{marker}" if stdout_text else marker
+
+
 def _execute_remote(
     code: str,
     task_id: Optional[str],
@@ -1238,9 +1251,7 @@ def _execute_remote(
             duration, timeout, tool_call_counter[0],
         )
     elif status == "interrupted":
-        result["output"] = (
-            stdout_text + "\n[execution interrupted — user sent a new message]"
-        )
+        result["output"] = _format_interrupted_output(stdout_text)
     elif exit_code != 0:
         result["status"] = "error"
         result["error"] = f"Script exited with code {exit_code}"
@@ -1710,7 +1721,7 @@ def execute_code(
                 duration, timeout, tool_call_counter[0],
             )
         elif status == "interrupted":
-            result["output"] = stdout_text + "\n[execution interrupted — user sent a new message]"
+            result["output"] = _format_interrupted_output(stdout_text)
         elif exit_code != 0:
             result["status"] = "error"
             result["error"] = stderr_text or f"Script exited with code {exit_code}"