diff --git a/libs/core/langchain_core/messages/tool.py b/libs/core/langchain_core/messages/tool.py
index 873f872cef268..25e6d368d8bd8 100644
--- a/libs/core/langchain_core/messages/tool.py
+++ b/libs/core/langchain_core/messages/tool.py
@@ -7,6 +7,7 @@
 
 from langchain_core.messages.base import BaseMessage, BaseMessageChunk, merge_content
 from langchain_core.utils._merge import merge_dicts, merge_obj
+import re
 
 
 class ToolOutputMixin:
@@ -209,6 +210,16 @@ class ToolCall(TypedDict):
 
 
 def tool_call(*, name: str, args: dict[str, Any], id: Optional[str]) -> ToolCall:
+    if isinstance(args, str):
+        try:
+            # Extract JSON-like dictionary from string using regex
+            match = re.search(r'\{.*\}', args)
+            if match:
+                args = json.loads(match.group())
+            else:
+                raise ValueError("No valid JSON object found in args string")
+        except json.JSONDecodeError:
+            raise ValueError("Invalid JSON string for args")
     return ToolCall(name=name, args=args, id=id, type="tool_call")