feat: Add extra_content field to ToolCall for provider-specific metadata

Author: loadchange

libs/core/langchain_core/messages/tool.py

@@ -227,25 +227,37 @@ class ToolCall(TypedDict):
 
     """
     type: NotRequired[Literal["tool_call"]]
+    extra_content: NotRequired[dict[str, Any]]
+    """Optional provider-specific metadata.
+
+    For example, Google's Gemini API returns thought_signature in:
+    extra_content.google.thought_signature
+
+    """
 
 
 def tool_call(
     *,
     name: str,
     args: dict[str, Any],
     id: str | None,
+    extra_content: dict[str, Any] | None = None,
 ) -> ToolCall:
     """Create a tool call.
 
     Args:
         name: The name of the tool to be called.
         args: The arguments to the tool call.
         id: An identifier associated with the tool call.
+        extra_content: Optional provider-specific metadata.
 
     Returns:
         The created tool call.
     """
-    return ToolCall(name=name, args=args, id=id, type="tool_call")
+    result = ToolCall(name=name, args=args, id=id, type="tool_call")
+    if extra_content is not None:
+        result["extra_content"] = extra_content
+    return result
 
 
 class ToolCallChunk(TypedDict):
@@ -347,6 +359,7 @@ def default_tool_parser(
                 name=function_name or "",
                 args=function_args or {},
                 id=raw_tool_call.get("id"),
+                extra_content=raw_tool_call.get("extra_content"),
             )
             tool_calls.append(parsed)
         except json.JSONDecodeError:

libs/core/langchain_core/output_parsers/openai_tools.py

@@ -72,6 +72,9 @@ def parse_tool_call(
     }
     if return_id:
         parsed["id"] = raw_tool_call.get("id")
+        # Preserve extra_content if present (e.g., for Google's thought_signature)
+        if "extra_content" in raw_tool_call:
+            parsed["extra_content"] = raw_tool_call["extra_content"]
         parsed = create_tool_call(**parsed)  # type: ignore[assignment,arg-type]
     return parsed
 

libs/core/tests/unit_tests/prompts/__snapshots__/test_chat.ambr

@@ -988,6 +988,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -2404,6 +2408,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({

libs/core/tests/unit_tests/runnables/__snapshots__/test_graph.ambr

@@ -1412,6 +1412,10 @@
                   'title': 'Args',
                   'type': 'object',
                 }),
+                'extra_content': dict({
+                  'title': 'Extra Content',
+                  'type': 'object',
+                }),
                 'id': dict({
                   'anyOf': list([
                     dict({

libs/core/tests/unit_tests/runnables/__snapshots__/test_runnable.ambr

@@ -2932,6 +2932,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -4410,6 +4414,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -5900,6 +5908,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -7246,6 +7258,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -8766,6 +8782,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -10157,6 +10177,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -11596,6 +11620,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({
@@ -13036,6 +13064,10 @@
             'title': 'Args',
             'type': 'object',
           }),
+          'extra_content': dict({
+            'title': 'Extra Content',
+            'type': 'object',
+          }),
           'id': dict({
             'anyOf': list([
               dict({

libs/partners/openai/langchain_openai/chat_models/base.py

@@ -3406,14 +3406,18 @@ def _is_pydantic_class(obj: Any) -> bool:
 
 
 def _lc_tool_call_to_openai_tool_call(tool_call: ToolCall) -> dict:
-    return {
+    result = {
         "type": "function",
         "id": tool_call["id"],
         "function": {
             "name": tool_call["name"],
             "arguments": json.dumps(tool_call["args"], ensure_ascii=False),
         },
     }
+    # Include extra_content if present (for thought_signature, etc.)
+    if "extra_content" in tool_call:
+        result["extra_content"] = tool_call["extra_content"]
+    return result
 
 
 def _lc_invalid_tool_call_to_openai_tool_call(