Change apply_update / _update_settings return type from set[str] to dict[str, Any]. The dict maps each changed field name to its pre-update value, enabling services to do granular diffing of complex settings objects. Existing call-site patterns ("field" in changed, if changed, iteration) work unchanged; set-difference sites use changed.keys() - {...}.

src/pipecat/services/gradium/stt.py

@@ -13,7 +13,7 @@ WebSocket API for streaming audio transcription.
 import base64
 import json
 from dataclasses import dataclass, field
-from typing import AsyncGenerator, Optional
+from typing import Any, AsyncGenerator, Optional
 
 from loguru import logger
 from pydantic import BaseModel
@@ -171,14 +171,14 @@ class GradiumSTTService(WebsocketSTTService):
         """
         return True
 
-    async def _update_settings(self, update: STTSettings) -> set[str]:
+    async def _update_settings(self, update: STTSettings) -> dict[str, Any]:
         """Apply a settings update, sync params, and reconnect.
 
         Args:
             update: A :class:`STTSettings` (or ``GradiumSTTSettings``) delta.
 
         Returns:
-            Set of field names whose values actually changed.
+            Dict mapping changed field names to their previous values.
         """
         changed = await super()._update_settings(update)
         if not changed: