diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index c35a470c..19c3fdc1 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -2,7 +2,7 @@ name: test
 
 on:
   pull_request:
-    paths:
+    paths-ignore:
       - 'examples/**'
       - '**/README.md'
 
diff --git a/ollama/_types.py b/ollama/_types.py
index bcf88969..5be4850b 100644
--- a/ollama/_types.py
+++ b/ollama/_types.py
@@ -23,7 +23,42 @@ def __setitem__(self, key: str, value: Any) -> None:
     setattr(self, key, value)
 
   def __contains__(self, key: str) -> bool:
-    return hasattr(self, key)
+    """
+    >>> msg = Message(role='user')
+    >>> 'nonexistent' in msg
+    False
+    >>> 'role' in msg
+    True
+    >>> 'content' in msg
+    False
+    >>> msg.content = 'hello!'
+    >>> 'content' in msg
+    True
+    >>> msg = Message(role='user', content='hello!')
+    >>> 'content' in msg
+    True
+    >>> 'tool_calls' in msg
+    False
+    >>> msg['tool_calls'] = []
+    >>> 'tool_calls' in msg
+    True
+    >>> msg['tool_calls'] = [Message.ToolCall(function=Message.ToolCall.Function(name='foo', arguments={}))]
+    >>> 'tool_calls' in msg
+    True
+    >>> msg['tool_calls'] = None
+    >>> 'tool_calls' in msg
+    True
+    >>> tool = Tool()
+    >>> 'type' in tool
+    True
+    """
+    if key in self.model_fields_set:
+      return True
+
+    if key in self.model_fields:
+      return self.model_fields[key].default is not None
+
+    return False
 
   def get(self, key: str, default: Any = None) -> Any:
     return getattr(self, key, default)