diff --git a/src/pipecat/pipeline/task.py b/src/pipecat/pipeline/task.py
index e47c0f849..692f325d9 100644
--- a/src/pipecat/pipeline/task.py
+++ b/src/pipecat/pipeline/task.py
@@ -9,7 +9,7 @@ import time
 from typing import Any, AsyncIterable, Dict, Iterable, List, Optional, Tuple, Type
 
 from loguru import logger
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, Field
 
 from pipecat.clocks.base_clock import BaseClock
 from pipecat.clocks.system_clock import SystemClock
@@ -69,10 +69,10 @@ class PipelineParams(BaseModel):
     enable_metrics: bool = False
     enable_usage_metrics: bool = False
     heartbeats_period_secs: float = HEARTBEAT_SECONDS
-    observers: List[BaseObserver] = []
+    observers: List[BaseObserver] = Field(default_factory=list)
     report_only_initial_ttfb: bool = False
     send_initial_empty_metrics: bool = True
-    start_metadata: Dict[str, Any] = {}
+    start_metadata: Dict[str, Any] = Field(default_factory=dict)
 
 
 class PipelineTaskSource(FrameProcessor):
diff --git a/src/pipecat/processors/frameworks/rtvi.py b/src/pipecat/processors/frameworks/rtvi.py
index 7bd54237d..771c5a3e2 100644
--- a/src/pipecat/processors/frameworks/rtvi.py
+++ b/src/pipecat/processors/frameworks/rtvi.py
@@ -110,7 +110,7 @@ class RTVIActionArgument(BaseModel):
 class RTVIAction(BaseModel):
     service: str
     action: str
-    arguments: List[RTVIActionArgument] = []
+    arguments: List[RTVIActionArgument] = Field(default_factory=list)
     result: Literal["bool", "number", "string", "array", "object"]
     handler: Callable[["RTVIProcessor", str, Dict[str, Any]], Awaitable[ActionResult]] = Field(
         exclude=True
diff --git a/src/pipecat/services/openai_realtime_beta/events.py b/src/pipecat/services/openai_realtime_beta/events.py
index c2dcb7f09..6fa38a8a1 100644
--- a/src/pipecat/services/openai_realtime_beta/events.py
+++ b/src/pipecat/services/openai_realtime_beta/events.py
@@ -115,7 +115,7 @@ class ResponseProperties(BaseModel):
     instructions: Optional[str] = None
     voice: Optional[str] = None
     output_audio_format: Optional[Literal["pcm16", "g711_ulaw", "g711_alaw"]] = None
-    tools: Optional[List[Dict]] = []
+    tools: Optional[List[Dict]] = Field(default_factory=list)
     tool_choice: Optional[Literal["auto", "none", "required"]] = None
     temperature: Optional[float] = None
     max_response_output_tokens: Optional[Union[int, Literal["inf"]]] = None
diff --git a/src/pipecat/transports/base_transport.py b/src/pipecat/transports/base_transport.py
index 91270c365..c634babb8 100644
--- a/src/pipecat/transports/base_transport.py
+++ b/src/pipecat/transports/base_transport.py
@@ -7,7 +7,7 @@
 from abc import abstractmethod
 from typing import List, Mapping, Optional
 
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, Field
 
 from pipecat.audio.filters.base_audio_filter import BaseAudioFilter
 from pipecat.audio.mixers.base_audio_mixer import BaseAudioMixer
@@ -34,7 +34,7 @@ class TransportParams(BaseModel):
     audio_out_bitrate: int = 96000
     audio_out_10ms_chunks: int = 4
     audio_out_mixer: Optional[BaseAudioMixer | Mapping[Optional[str], BaseAudioMixer]] = None
-    audio_out_destinations: List[str] = []
+    audio_out_destinations: List[str] = Field(default_factory=list)
     audio_in_enabled: bool = False
     audio_in_sample_rate: Optional[int] = None
     audio_in_channels: int = 1
@@ -49,7 +49,7 @@ class TransportParams(BaseModel):
     video_out_bitrate: int = 800000
     video_out_framerate: int = 30
     video_out_color_format: str = "RGB"
-    video_out_destinations: List[str] = []
+    video_out_destinations: List[str] = Field(default_factory=list)
     vad_enabled: bool = False
     vad_audio_passthrough: bool = False
     vad_analyzer: Optional[VADAnalyzer] = None