diff --git a/modules/serviceCenter/services/serviceAgent/sandboxExecutor.py b/modules/serviceCenter/services/serviceAgent/sandboxExecutor.py
index 1882d7eb..15362e65 100644
--- a/modules/serviceCenter/services/serviceAgent/sandboxExecutor.py
+++ b/modules/serviceCenter/services/serviceAgent/sandboxExecutor.py
@@ -3,7 +3,6 @@
 """Sandboxed code execution for the AI agent executeCode tool."""
 
 import logging
-import signal
 import sys
 import io
 import traceback
@@ -72,15 +71,12 @@ async def executePython(code: str) -> Dict[str, Any]:
             sys.stdout = capturedOutput
             sys.stderr = capturedOutput
 
-            if sys.platform != "win32":
-                signal.signal(signal.SIGALRM, lambda *_: (_ for _ in ()).throw(TimeoutError("Execution timed out")))
-                signal.alarm(_MAX_EXECUTION_TIME_S)
+            # Do not use signal.SIGALRM here: _run executes inside a thread-pool worker
+            # (asyncio.run_in_executor). signal.signal only works on the main thread.
+            # Wall-clock limit is enforced by asyncio.wait_for around run_in_executor.
 
             exec(compile(code, "<sandbox>", "exec"), restrictedGlobals)
 
-            if sys.platform != "win32":
-                signal.alarm(0)
-
             output = capturedOutput.getvalue()
             if len(output) > _MAX_OUTPUT_CHARS:
                 output = output[:_MAX_OUTPUT_CHARS] + f"\n... (truncated at {_MAX_OUTPUT_CHARS} chars)"
@@ -94,14 +90,12 @@ async def executePython(code: str) -> Dict[str, Any]:
         finally:
             sys.stdout = oldStdout
             sys.stderr = oldStderr
-            if sys.platform != "win32":
-                signal.alarm(0)
 
     loop = asyncio.get_event_loop()
     try:
         result = await asyncio.wait_for(
             loop.run_in_executor(None, _run),
-            timeout=_MAX_EXECUTION_TIME_S + 5,
+            timeout=float(_MAX_EXECUTION_TIME_S) + 5.0,
         )
         return result
     except asyncio.TimeoutError: