diff --git a/mirascope/core/mistral/_utils/_convert_message_params.py b/mirascope/core/mistral/_utils/_convert_message_params.py
index 2b3065850..00e2740cf 100644
--- a/mirascope/core/mistral/_utils/_convert_message_params.py
+++ b/mirascope/core/mistral/_utils/_convert_message_params.py
@@ -1,5 +1,7 @@
 """Utility for converting `BaseMessageParam` to `ChatMessage`."""
 
+from typing import Any
+
 from mistralai.models import (
     AssistantMessage,
     SystemMessage,
@@ -10,26 +12,36 @@
 from ...base import BaseMessageParam
 
 
+def make_message(
+    role: str,
+    **kwargs,  # noqa: ANN003
+) -> AssistantMessage | SystemMessage | ToolMessage | UserMessage:
+    if role == "assistant":
+        return AssistantMessage(**kwargs)
+    elif role == "system":
+        return SystemMessage(**kwargs)
+    elif role == "tool":
+        return ToolMessage(**kwargs)
+    elif role == "user":
+        return UserMessage(**kwargs)
+    raise ValueError(f"Invalid role: {role}")
+
+
 def convert_message_params(
     message_params: list[
         BaseMessageParam | AssistantMessage | SystemMessage | ToolMessage | UserMessage
     ],
-) -> list[BaseMessageParam]:
+) -> list[AssistantMessage | SystemMessage | ToolMessage | UserMessage]:
     converted_message_params = []
     for message_param in message_params:
-        if not isinstance(
-            message_param,
-            BaseMessageParam,
-        ):
+        if not isinstance(message_param, BaseMessageParam):
             converted_message_params.append(message_param)
         elif isinstance(content := message_param.content, str):
-            converted_message_params.append(
-                BaseMessageParam(**message_param.model_dump())
-            )
+            converted_message_params.append(make_message(**message_param.model_dump()))
         else:
             if len(content) != 1 or content[0].type != "text":
                 raise ValueError("Mistral currently only supports text parts.")
             converted_message_params.append(
-                BaseMessageParam(role=message_param.role, content=content[0].text)
+                make_message(role=message_param.role, content=content[0].text)
             )
     return converted_message_params
diff --git a/mirascope/core/mistral/_utils/_setup_call.py b/mirascope/core/mistral/_utils/_setup_call.py
index 10c071fe5..c8bb09689 100644
--- a/mirascope/core/mistral/_utils/_setup_call.py
+++ b/mirascope/core/mistral/_utils/_setup_call.py
@@ -19,10 +19,9 @@
     UserMessage,
 )
 
-from mirascope.core.base._utils._protocols import fn_is_async
-
-from ...base import BaseMessageParam, BaseTool, _utils
+from ...base import BaseTool, _utils
 from ...base._utils import AsyncCreateFn, CreateFn, get_async_create_fn, get_create_fn
+from ...base._utils._protocols import fn_is_async
 from ..call_kwargs import MistralCallKwargs
 from ..call_params import MistralCallParams
 from ..dynamic_config import MistralDynamicConfig
diff --git a/mirascope/core/mistral/call_response.py b/mirascope/core/mistral/call_response.py
index 01218544f..dfe70dbec 100644
--- a/mirascope/core/mistral/call_response.py
+++ b/mirascope/core/mistral/call_response.py
@@ -3,7 +3,7 @@
 usage docs: learn/calls.md#handling-responses
 """
 
-from typing import Any
+from typing import Any, cast
 
 from mistralai.models import (
     AssistantMessage,
@@ -30,7 +30,7 @@ class MistralCallResponse(
         MistralDynamicConfig,
         AssistantMessage | SystemMessage | ToolMessage | UserMessage,
         MistralCallParams,
-        AssistantMessage | SystemMessage | ToolMessage | UserMessage,
+        UserMessage,
     ]
 ):
     """A convenience wrapper around the Mistral `ChatCompletion` response.
@@ -104,9 +104,9 @@ def cost(self) -> float | None:
     @property
     def message_param(
         self,
-    ) -> AssistantMessage | SystemMessage | ToolMessage | UserMessage:
+    ) -> AssistantMessage:
         """Returns the assistants's response as a message parameter."""
-        return self.response.choices[0].message
+        return cast(AssistantMessage, self.response.choices[0].message)
 
     @computed_field
     @property
@@ -144,7 +144,7 @@ def tool(self) -> MistralTool | None:
     @classmethod
     def tool_message_params(
         cls, tools_and_outputs: list[tuple[MistralTool, str]]
-    ) -> list[AssistantMessage | SystemMessage | ToolMessage | UserMessage]:
+    ) -> list[ToolMessage]:
         """Returns the tool message parameters for tool call results.
 
         Args:
diff --git a/mirascope/core/mistral/stream.py b/mirascope/core/mistral/stream.py
index 7fe483766..d2f0af846 100644
--- a/mirascope/core/mistral/stream.py
+++ b/mirascope/core/mistral/stream.py
@@ -29,9 +29,9 @@ class MistralStream(
     BaseStream[
         MistralCallResponse,
         MistralCallResponseChunk,
-        AssistantMessage | SystemMessage | ToolMessage | UserMessage,
-        AssistantMessage | SystemMessage | ToolMessage | UserMessage,
-        AssistantMessage | SystemMessage | ToolMessage | UserMessage,
+        UserMessage,
+        AssistantMessage,
+        ToolMessage,
         AssistantMessage | SystemMessage | ToolMessage | UserMessage,
         MistralTool,
         dict[str, Any],
@@ -69,7 +69,7 @@ def cost(self) -> float | None:
 
     def _construct_message_param(
         self, tool_calls: list | None = None, content: str | None = None
-    ) -> AssistantMessage | SystemMessage | ToolMessage | UserMessage:
+    ) -> AssistantMessage:
         message_param = AssistantMessage(
             content=content if content else "", tool_calls=tool_calls
         )
diff --git a/tests/core/mistral/_utils/test_convert_message_params.py b/tests/core/mistral/_utils/test_convert_message_params.py
index bf35f6c2b..eefbd0f49 100644
--- a/tests/core/mistral/_utils/test_convert_message_params.py
+++ b/tests/core/mistral/_utils/test_convert_message_params.py
@@ -25,8 +25,8 @@ def test_convert_message_params() -> None:
     converted_message_params = convert_message_params(message_params)
     assert converted_message_params == [
         UserMessage(content="Hello"),
-        BaseMessageParam(role="user", content="Hello"),
-        BaseMessageParam(role="user", content="Hello"),
+        UserMessage(role="user", content="Hello"),
+        UserMessage(role="user", content="Hello"),
     ]
 
     with pytest.raises(