diff --git a/ollama/_types.py b/ollama/_types.py
index 96529d63..d9f0ad4f 100644
--- a/ollama/_types.py
+++ b/ollama/_types.py
@@ -346,6 +346,9 @@ class Function(SubscriptableBaseModel):
       arguments: Mapping[str, Any]
       'Arguments of the function.'
 
+    id: Optional[str] = None
+    'Identifier of the tool call, when provided by the server.'
+
     function: Function
     'Function to be called.'
 
diff --git a/tests/test_type_serialization.py b/tests/test_type_serialization.py
index f458cd23..d2ac0b6a 100644
--- a/tests/test_type_serialization.py
+++ b/tests/test_type_serialization.py
@@ -4,7 +4,7 @@
 
 import pytest
 
-from ollama._types import CreateRequest, Image
+from ollama._types import CreateRequest, Image, Message
 
 
 def test_image_serialization_bytes():
@@ -31,6 +31,22 @@ def test_image_serialization_plain_string():
   assert img.model_dump() == 'not a path or base64'  # Should return as-is
 
 
+def test_tool_call_id_round_trips():
+  # The server sends an `id` on each tool call (e.g. "call_p7o2gz50"); it must survive parsing.
+  message = Message(
+    role='assistant',
+    tool_calls=[{'id': 'call_p7o2gz50', 'function': {'name': 'test_function', 'arguments': {'param1': 'test1'}}}],
+  )
+  assert message.tool_calls[0].id == 'call_p7o2gz50'
+  assert message.tool_calls[0].function.name == 'test_function'
+  assert message.model_dump()['tool_calls'][0]['id'] == 'call_p7o2gz50'
+
+
+def test_tool_call_id_defaults_to_none():
+  message = Message(role='assistant', tool_calls=[{'function': {'name': 'f', 'arguments': {}}}])
+  assert message.tool_calls[0].id is None
+
+
 def test_image_serialization_path():
   with tempfile.NamedTemporaryFile() as temp_file:
     temp_file.write(b'test file content')