diff --git a/src/openai_schemas.py b/src/openai_schemas.py
index 9f4a0928..0058a4be 100644
--- a/src/openai_schemas.py
+++ b/src/openai_schemas.py
@@ -48,7 +48,7 @@ class ToolCall:
 @dataclass(frozen=True)
 class ChatMessage:
  role: str
- content: str
+ content: str | list  # str for text; list of content parts for multimodal (text + image_url, etc.)
  tool_calls: Optional[tuple[ToolCall, ...]] = None
  tool_call_id: Optional[str] = None
  name: Optional[str] = None