diff --git a/pyproject.toml b/pyproject.toml
index b11c7bd..03faef9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -96,3 +96,6 @@ from-first = true
 # import-heading-firstparty=First Party
 # import-heading-localfolder=Local
 known-local-folder = ["tuning"]
+
+[tool.mypy]
+ignore_missing_imports = true
diff --git a/src/instructlab/eval/mt_bench_common.py b/src/instructlab/eval/mt_bench_common.py
index aa0b901..2b80efb 100644
--- a/src/instructlab/eval/mt_bench_common.py
+++ b/src/instructlab/eval/mt_bench_common.py
@@ -4,7 +4,7 @@
 """
 
 # Standard
-from typing import Optional
+from typing import Optional, TypedDict
 import ast
 import dataclasses
 import glob
@@ -14,6 +14,7 @@
 import time
 
 # Third Party
+from fastchat import conversation
 from fastchat.model.model_adapter import get_conversation_template  # type: ignore
 import openai
 
@@ -254,23 +255,44 @@ def _is_fatal_openai_error(e: openai.OpenAIError) -> bool:
     return isinstance(e, openai.APIConnectionError)
 
 
+# TODO: copied from instructlab (cli) utils module; consolidate somewhere?
+class Message(TypedDict):
+    """
+    Represents a message within an AI conversation.
+    """
+
+    content: str
+    # one of: "user", "assistant", or "system"
+    role: str
+
+
+def _get_messages(
+    conv: conversation.Conversation, merge_system_user_message: bool
+) -> list[Message]:
+    messages = conv.to_openai_api_messages()
+    if (
+        merge_system_user_message
+        and messages[0]["role"] == "system"
+        and messages[1]["role"] == "user"
+    ):
+        messages[1]["content"] = messages[0]["content"] + "\n" + messages[1]["content"]
+        return messages[1:]
+    return messages
+
+
 def chat_completion_openai(
-    openai_client, model, conv, temperature, max_tokens, merge_system_user_message=False
+    openai_client,
+    model,
+    conv: conversation.Conversation,
+    temperature,
+    max_tokens,
+    merge_system_user_message: bool = False,
 ) -> str:
     output = None
+    messages = _get_messages(conv, merge_system_user_message)
 
     for i in range(API_MAX_RETRY):
         try:
-            messages = conv.to_openai_api_messages()
-            if (
-                merge_system_user_message
-                and messages[0]["role"] == "system"
-                and messages[1]["role"] == "user"
-            ):
-                messages[1]["content"] = (
-                    messages[0]["content"] + "\n" + messages[1]["content"]
-                )
-                messages = messages[1:]
             response = openai_client.chat.completions.create(
                 model=model,
                 messages=messages,