diff --git a/src/transcription/providers/openrouter.py b/src/transcription/providers/openrouter.py
index 7382a0a..4e6b9e2 100644
--- a/src/transcription/providers/openrouter.py
+++ b/src/transcription/providers/openrouter.py
@@ -6,8 +6,10 @@ import base64
 import logging
 from dataclasses import dataclass
 from typing import Any
+from typing import cast
 
 from openrouter import OpenRouter
+from openrouter.components.chatmessages import ChatMessagesTypedDict
 
 from transcription.config import Settings
 from transcription.config import get_settings
@@ -49,7 +51,7 @@ class OpenRouterTranscriptionProvider:
         request = self._build_request(prompt_text=prompt_text, image_bytes=image_bytes, mime_type=mime_type)
         try:
             response = await self._client.chat.send_async(
-                messages=request.messages,
+                messages=cast(list[ChatMessagesTypedDict], request.messages),
                 model=request.model,
                 http_referer=request.http_referer,
                 x_open_router_title=request.x_open_router_title,