diff --git a/python/restate/ext/langchain/_middleware.py b/python/restate/ext/langchain/_middleware.py
index 8b6c70f..1f0aa87 100644
--- a/python/restate/ext/langchain/_middleware.py
+++ b/python/restate/ext/langchain/_middleware.py
@@ -128,6 +128,8 @@ async def awrap_tool_call(
             await turnstile.wait_for(tool_call_id)
             result = await handler(request)
             turnstile.allow_next_after(tool_call_id)
+            if isinstance(result, ToolMessage):
+                result.id = str(ctx.uuid())
             return result
         except BaseException:
             # Unblock the rest of the parallel tool batch, then propagate.