chore(python-sdk): add type literals for new events

Add type literals for the new event types in the Python SDK, so users
don't have to manually set the type field when creating event instances.

Author: stevenh

python-sdk/ag_ui/core/events.py

@@ -87,24 +87,20 @@ class ThinkingTextMessageStartEvent(BaseEvent):
     """
     Event indicating the start of a thinking text message.
     """
-    type: Literal[EventType.THINKING_TEXT_MESSAGE_START]
+    type: Literal[EventType.THINKING_TEXT_MESSAGE_START] = EventType.THINKING_TEXT_MESSAGE_START  # pyright: ignore[reportIncompatibleVariableOverride]
 
 class ThinkingTextMessageContentEvent(BaseEvent):
     """
     Event indicating a piece of a thinking text message.
     """
-    type: Literal[EventType.THINKING_TEXT_MESSAGE_CONTENT]
-    delta: str  # This should not be an empty string
-
-    def model_post_init(self, __context):
-        if len(self.delta) == 0:
-            raise ValueError("Delta must not be an empty string")
+    type: Literal[EventType.THINKING_TEXT_MESSAGE_CONTENT] = EventType.THINKING_TEXT_MESSAGE_CONTENT  # pyright: ignore[reportIncompatibleVariableOverride]
+    delta: str = Field(min_length=1)
 
 class ThinkingTextMessageEndEvent(BaseEvent):
     """
     Event indicating the end of a thinking text message.
     """
-    type: Literal[EventType.THINKING_TEXT_MESSAGE_END]
+    type: Literal[EventType.THINKING_TEXT_MESSAGE_END] = EventType.THINKING_TEXT_MESSAGE_END  # pyright: ignore[reportIncompatibleVariableOverride]
 
 class ToolCallStartEvent(BaseEvent):
     """
@@ -147,7 +143,7 @@ class ToolCallResultEvent(BaseEvent):
     Event containing the result of a tool call.
     """
     message_id: str
-    type: Literal[EventType.TOOL_CALL_RESULT]
+    type: Literal[EventType.TOOL_CALL_RESULT] = EventType.TOOL_CALL_RESULT  # pyright: ignore[reportIncompatibleVariableOverride]
     tool_call_id: str
     content: str
     role: Optional[Literal["tool"]] = None
@@ -156,14 +152,14 @@ class ThinkingStartEvent(BaseEvent):
     """
     Event indicating the start of a thinking step event.
     """
-    type: Literal[EventType.THINKING_START]
+    type: Literal[EventType.THINKING_START] = EventType.THINKING_START  # pyright: ignore[reportIncompatibleVariableOverride]
     title: Optional[str] = None
 
 class ThinkingEndEvent(BaseEvent):
     """
     Event indicating the end of a thinking step event.
     """
-    type: Literal[EventType.THINKING_END]
+    type: Literal[EventType.THINKING_END] = EventType.THINKING_END  # pyright: ignore[reportIncompatibleVariableOverride]
 
 class StateSnapshotEvent(BaseEvent):
     """