diff --git a/src/controlflow/llm/rules.py b/src/controlflow/llm/rules.py
index fed84d9c..e431e5be 100644
--- a/src/controlflow/llm/rules.py
+++ b/src/controlflow/llm/rules.py
@@ -1,8 +1,9 @@
 import textwrap
-from typing import Optional
+from typing import Any, Optional, Union
 
 from langchain_anthropic import ChatAnthropic
 from langchain_openai import AzureChatOpenAI, ChatOpenAI
+from pydantic import Field
 
 from controlflow.llm.models import BaseChatModel
 from controlflow.utilities.general import ControlFlowModel, unwrap
@@ -17,7 +18,7 @@ class LLMRules(ControlFlowModel):
     necessary.
     """
 
-    model: Optional[BaseChatModel]
+    model: Any
 
     # require at least one non-system message
     require_at_least_one_message: bool = False
@@ -54,7 +55,7 @@ def model_instructions(self) -> Optional[list[str]]:
 class OpenAIRules(LLMRules):
     require_message_name_format: str = r"[^a-zA-Z0-9_-]"
 
-    model: ChatOpenAI
+    model: Any
 
     def model_instructions(self) -> list[str]:
         instructions = []