diff --git a/pyrightconfig.json b/pyrightconfig.json
index d882b2106..0e54af4c7 100644
--- a/pyrightconfig.json
+++ b/pyrightconfig.json
@@ -37,58 +37,39 @@
     "src/pipecat/services/deepgram/sagemaker/tts.py",
     "src/pipecat/services/deepgram/tts.py",
     "src/pipecat/services/elevenlabs/tts.py",
-    "src/pipecat/services/fish/tts.py",
-    "src/pipecat/services/gladia/stt.py",
     "src/pipecat/services/google/gemini_live/llm.py",
     "src/pipecat/services/google/gemini_live/vertex/llm.py",
-    "src/pipecat/services/google/image.py",
     "src/pipecat/services/google/llm.py",
     "src/pipecat/services/google/stt.py",
     "src/pipecat/services/google/tts.py",
     "src/pipecat/services/gradium/stt.py",
-    "src/pipecat/services/groq/tts.py",
     "src/pipecat/services/heygen/api_interactive_avatar.py",
-    "src/pipecat/services/heygen/base_api.py",
     "src/pipecat/services/heygen/client.py",
     "src/pipecat/services/heygen/video.py",
-    "src/pipecat/services/hume/tts.py",
     "src/pipecat/services/inworld/realtime/llm.py",
-    "src/pipecat/services/inworld/tts.py",
-    "src/pipecat/services/kokoro/tts.py",
     "src/pipecat/services/llm_service.py",
-    "src/pipecat/services/lmnt/tts.py",
     "src/pipecat/services/mem0/memory.py",
     "src/pipecat/services/mistral/stt.py",
     "src/pipecat/services/mistral/tts.py",
     "src/pipecat/services/moondream/vision.py",
-    "src/pipecat/services/neuphonic/tts.py",
     "src/pipecat/services/nvidia/stt.py",
     "src/pipecat/services/nvidia/tts.py",
     "src/pipecat/services/openai/base_llm.py",
     "src/pipecat/services/openai/image.py",
-    "src/pipecat/services/openai/llm.py",
     "src/pipecat/services/openai/realtime/llm.py",
     "src/pipecat/services/openai/responses/llm.py",
     "src/pipecat/services/openai/stt.py",
-    "src/pipecat/services/openai/tts.py",
-    "src/pipecat/services/openrouter/llm.py",
-    "src/pipecat/services/piper/tts.py",
-    "src/pipecat/services/resembleai/tts.py",
     "src/pipecat/services/rime/tts.py",
     "src/pipecat/services/sambanova/llm.py",
     "src/pipecat/services/sarvam/stt.py",
-    "src/pipecat/services/sarvam/tts.py",
     "src/pipecat/services/simli/video.py",
-    "src/pipecat/services/smallest/tts.py",
     "src/pipecat/services/speechmatics/stt.py",
     "src/pipecat/services/stt_service.py",
     "src/pipecat/services/tavus/video.py",
     "src/pipecat/services/tts_service.py",
     "src/pipecat/services/ultravox/llm.py",
-    "src/pipecat/services/websocket_service.py",
     "src/pipecat/services/whisper/stt.py",
     "src/pipecat/services/xai/realtime/llm.py",
-    "src/pipecat/services/xtts/tts.py",
     "src/pipecat/transports/base_output.py",
     "src/pipecat/transports/daily/transport.py",
     "src/pipecat/transports/heygen/transport.py",
diff --git a/src/pipecat/services/gladia/stt.py b/src/pipecat/services/gladia/stt.py
index cc8e5279b..26fea653c 100644
--- a/src/pipecat/services/gladia/stt.py
+++ b/src/pipecat/services/gladia/stt.py
@@ -542,6 +542,8 @@ class GladiaSTTService(WebsocketSTTService):
 
             logger.debug(f"{self}Connecting to Gladia WebSocket")
 
+            if self._session_url is None:
+                raise RuntimeError(f"{self} session URL is not initialized")
             self._websocket = await websocket_connect(self._session_url)
             self._connection_active = True
 
diff --git a/src/pipecat/services/google/image.py b/src/pipecat/services/google/image.py
index 1ed8adc2c..bada7d0d6 100644
--- a/src/pipecat/services/google/image.py
+++ b/src/pipecat/services/google/image.py
@@ -30,7 +30,7 @@ from pipecat.services.image_service import ImageGenService
 from pipecat.services.settings import NOT_GIVEN, ImageGenSettings, _NotGiven, assert_given
 
 try:
-    from google import genai
+    import google.genai as genai
     from google.genai import types
 except ModuleNotFoundError as e:
     logger.error(f"Exception: {e}")
@@ -153,8 +153,12 @@ class GoogleImageGenService(ImageGenService):
         await self.start_ttfb_metrics()
 
         try:
+            model = assert_given(self._settings.model)
+            if model is None:
+                yield ErrorFrame("Google image generation model must be specified")
+                return
             response = await self._client.aio.models.generate_images(
-                model=self._settings.model,
+                model=model,
                 prompt=prompt,
                 config=types.GenerateImagesConfig(
                     number_of_images=assert_given(self._settings.number_of_images),
@@ -169,8 +173,9 @@ class GoogleImageGenService(ImageGenService):
 
             for img_response in response.generated_images:
                 # Google returns the image data directly
-                image_bytes = img_response.image.image_bytes
-                image = Image.open(io.BytesIO(image_bytes))
+                if img_response.image is None or img_response.image.image_bytes is None:
+                    continue
+                image = Image.open(io.BytesIO(img_response.image.image_bytes))
 
                 frame = URLImageRawFrame(
                     url=None,  # Google doesn't provide URLs, only image data
diff --git a/src/pipecat/services/google/llm.py b/src/pipecat/services/google/llm.py
index da9659872..599c203ab 100644
--- a/src/pipecat/services/google/llm.py
+++ b/src/pipecat/services/google/llm.py
@@ -52,7 +52,7 @@ from pipecat.utils.tracing.service_decorators import traced_llm
 os.environ["GRPC_ENABLE_FORK_SUPPORT"] = "false"
 
 try:
-    from google import genai
+    import google.genai as genai
     from google.api_core.exceptions import DeadlineExceeded
     from google.genai.types import (
         GenerateContentConfig,
diff --git a/src/pipecat/services/groq/tts.py b/src/pipecat/services/groq/tts.py
index 36e01ff8b..00038f2f0 100644
--- a/src/pipecat/services/groq/tts.py
+++ b/src/pipecat/services/groq/tts.py
@@ -10,6 +10,7 @@ import io
 import wave
 from collections.abc import AsyncGenerator
 from dataclasses import dataclass, field
+from typing import Literal, cast
 
 from loguru import logger
 from pydantic import BaseModel
@@ -31,6 +32,19 @@ except ModuleNotFoundError as e:
     logger.error("In order to use Groq, you need to `pip install pipecat-ai[groq]`.")
     raise Exception(f"Missing module: {e}")
 
+# Hint set for `output_format`. The values mirror the Literal that
+# `groq.resources.audio.speech.AsyncSpeech.create` accepts on its
+# `response_format` parameter (also visible as the `response_format` field of
+# `groq.types.audio.SpeechCreateParams`). The groq SDK does not export this as
+# a named alias, so we redeclare it here.
+#
+# This alias is used in unions like `GroqAudioFormat | str`, so pyright shows
+# these values as completion hints without rejecting other strings. If groq
+# adds a new format before this list is updated, callers can still pass it and
+# we forward it through (with a cast at the API boundary). Keep in sync on a
+# best-effort basis when bumping the groq dep.
+GroqAudioFormat = Literal["flac", "mp3", "mulaw", "ogg", "wav"]
+
 
 @dataclass
 class GroqTTSSettings(TTSSettings):
@@ -74,7 +88,7 @@ class GroqTTSService(TTSService):
         self,
         *,
         api_key: str,
-        output_format: str = "wav",
+        output_format: GroqAudioFormat | str = "wav",
         params: InputParams | None = None,
         model_name: str | None = None,
         voice_id: str | None = None,
@@ -147,7 +161,7 @@ class GroqTTSService(TTSService):
         )
 
         self._api_key = api_key
-        self._output_format = output_format
+        self._output_format: str = output_format
 
         self._client = AsyncGroq(api_key=self._api_key)
 
@@ -178,12 +192,18 @@ class GroqTTSService(TTSService):
             speed = assert_given(self._settings.speed)
             if model is None:
                 raise ValueError("Groq TTS model must be specified")
+            if voice is None:
+                raise ValueError("Groq TTS voice must be specified")
             if speed is None:
                 raise ValueError("Groq TTS speed must be specified")
             response = await self._client.audio.speech.create(
                 model=model,
                 voice=voice,
-                response_format=self._output_format,
+                # Cast satisfies groq's stricter Literal typing while letting
+                # callers pass any string (e.g. a newer groq format we haven't
+                # yet added to GroqAudioFormat). If the value is unsupported,
+                # groq's API will surface a runtime error with a clear message.
+                response_format=cast(GroqAudioFormat, self._output_format),
                 # Note: as of 2026-02-25, only a speed of 1.0 is supported, but
                 # here we pass it for completeness and future-proofing
                 speed=speed,
diff --git a/src/pipecat/services/heygen/base_api.py b/src/pipecat/services/heygen/base_api.py
index c866cfb11..57ca2e19e 100644
--- a/src/pipecat/services/heygen/base_api.py
+++ b/src/pipecat/services/heygen/base_api.py
@@ -33,8 +33,8 @@ class StandardSessionResponse(BaseModel):
     access_token: str
     livekit_agent_token: str
 
-    livekit_url: str = None
-    ws_url: str = None
+    livekit_url: str
+    ws_url: str
 
     raw_response: Any
 
diff --git a/src/pipecat/services/hume/tts.py b/src/pipecat/services/hume/tts.py
index ac17efd48..75a6d5b72 100644
--- a/src/pipecat/services/hume/tts.py
+++ b/src/pipecat/services/hume/tts.py
@@ -19,6 +19,7 @@ from pipecat import version as pipecat_version
 from pipecat.frames.frames import (
     CancelFrame,
     EndFrame,
+    ErrorFrame,
     Frame,
     InterruptionFrame,
     StartFrame,
@@ -289,10 +290,14 @@ class HumeTTSService(TTSService):
         """
         logger.debug(f"{self}: Generating Hume TTS: [{text}]")
 
+        voice_id = assert_given(self._settings.voice)
+        if voice_id is None:
+            yield ErrorFrame(error="Hume TTS voice must be specified")
+            return
         # Build the request payload
         utterance_kwargs: dict[str, Any] = {
             "text": text,
-            "voice": PostedUtteranceVoiceWithId(id=assert_given(self._settings.voice)),
+            "voice": PostedUtteranceVoiceWithId(id=voice_id),
         }
         if self._settings.description is not None:
             utterance_kwargs["description"] = self._settings.description
diff --git a/src/pipecat/services/inworld/tts.py b/src/pipecat/services/inworld/tts.py
index ef3f0f956..0e087082c 100644
--- a/src/pipecat/services/inworld/tts.py
+++ b/src/pipecat/services/inworld/tts.py
@@ -794,8 +794,10 @@ class InworldTTSService(WebsocketTTSService):
 
         return word_times
 
-    async def _close_context(self, context_id: str):
-        if context_id and self._websocket:
+    async def _close_context(self, context_id: str | None):
+        if not context_id:
+            return
+        if self._websocket:
             logger.info(f"{self}: Closing context {context_id} due to interruption or completion")
             try:
                 await self._send_close_context(context_id)
diff --git a/src/pipecat/services/kokoro/tts.py b/src/pipecat/services/kokoro/tts.py
index 81c90487f..dd96ee90b 100644
--- a/src/pipecat/services/kokoro/tts.py
+++ b/src/pipecat/services/kokoro/tts.py
@@ -216,6 +216,8 @@ class KokoroTTSService(TTSService):
             await self.start_tts_usage_metrics(text)
 
             voice = assert_given(self._settings.voice)
+            if voice is None:
+                raise ValueError("Kokoro TTS voice must be specified")
             lang = assert_given(self._settings.language)
             if lang is None:
                 raise ValueError("Kokoro TTS language must be specified")
diff --git a/src/pipecat/services/neuphonic/tts.py b/src/pipecat/services/neuphonic/tts.py
index 6a405a1d2..5f27efaf1 100644
--- a/src/pipecat/services/neuphonic/tts.py
+++ b/src/pipecat/services/neuphonic/tts.py
@@ -331,7 +331,10 @@ class NeuphonicTTSService(InterruptibleTTSService):
 
     async def _receive_messages(self):
         """Receive and process messages from Neuphonic WebSocket."""
-        async for message in self._websocket:
+        websocket = self._websocket
+        if websocket is None:
+            return
+        async for message in websocket:
             if isinstance(message, str):
                 msg = json.loads(message)
                 if msg.get("data") and msg["data"].get("audio"):
diff --git a/src/pipecat/services/openai/base_llm.py b/src/pipecat/services/openai/base_llm.py
index b5287067f..ae4b03560 100644
--- a/src/pipecat/services/openai/base_llm.py
+++ b/src/pipecat/services/openai/base_llm.py
@@ -66,7 +66,7 @@ class OpenAILLMSettings(LLMSettings):
     )
     top_p: float | None | _NotGiven | OpenAINotGiven = field(default_factory=lambda: _NOT_GIVEN)
     max_tokens: int | None | _NotGiven | OpenAINotGiven = field(default_factory=lambda: _NOT_GIVEN)
-    max_completion_tokens: int | _NotGiven | OpenAINotGiven = field(
+    max_completion_tokens: int | None | _NotGiven | OpenAINotGiven = field(
         default_factory=lambda: _NOT_GIVEN
     )
 
diff --git a/src/pipecat/services/openai/tts.py b/src/pipecat/services/openai/tts.py
index a0e6a93dd..a6528f59e 100644
--- a/src/pipecat/services/openai/tts.py
+++ b/src/pipecat/services/openai/tts.py
@@ -235,12 +235,22 @@ class OpenAITTSService(TTSService):
             Frame: Audio frames containing the synthesized speech data.
         """
         logger.debug(f"{self}: Generating TTS [{text}]")
+        voice = assert_given(self._settings.voice)
+        if voice is None:
+            yield ErrorFrame(error="OpenAI TTS voice must be specified")
+            return
+        if voice not in VALID_VOICES:
+            yield ErrorFrame(
+                error=f"OpenAI TTS voice {voice!r} is not supported "
+                f"(must be one of: {', '.join(sorted(VALID_VOICES))})"
+            )
+            return
         try:
             # Setup API parameters
             create_params = {
                 "input": text,
                 "model": self._settings.model,
-                "voice": VALID_VOICES[assert_given(self._settings.voice)],
+                "voice": VALID_VOICES[voice],
                 "response_format": "pcm",
             }
 
diff --git a/src/pipecat/services/openrouter/llm.py b/src/pipecat/services/openrouter/llm.py
index 624dd3141..4de5190dd 100644
--- a/src/pipecat/services/openrouter/llm.py
+++ b/src/pipecat/services/openrouter/llm.py
@@ -15,6 +15,7 @@ from typing import Any
 
 from loguru import logger
 
+from pipecat.adapters.services.open_ai_adapter import OpenAILLMInvocationParams
 from pipecat.services.openai.base_llm import BaseOpenAILLMService
 from pipecat.services.openai.llm import OpenAILLMService
 from pipecat.services.settings import assert_given
@@ -96,7 +97,9 @@ class OpenRouterLLMService(OpenAILLMService):
         logger.debug(f"Creating OpenRouter client with api {base_url}")
         return super().create_client(api_key, base_url, **kwargs)
 
-    def build_chat_completion_params(self, params_from_context: dict[str, Any]) -> dict[str, Any]:
+    def build_chat_completion_params(
+        self, params_from_context: OpenAILLMInvocationParams
+    ) -> dict[str, Any]:
         """Builds chat parameters, handling model-specific constraints.
 
         Args:
diff --git a/src/pipecat/services/piper/tts.py b/src/pipecat/services/piper/tts.py
index 5cc725c2c..1bb9eaac8 100644
--- a/src/pipecat/services/piper/tts.py
+++ b/src/pipecat/services/piper/tts.py
@@ -101,6 +101,8 @@ class PiperTTSService(TTSService):
         download_dir = download_dir or Path.cwd()
 
         _voice = assert_given(self._settings.voice)
+        if _voice is None:
+            raise ValueError("Piper TTS voice must be specified")
         model_file = f"{_voice}.onnx"
         model_path_resolved = Path(download_dir) / model_file
 
diff --git a/src/pipecat/services/resembleai/tts.py b/src/pipecat/services/resembleai/tts.py
index 3053e0b70..c1dfc8a92 100644
--- a/src/pipecat/services/resembleai/tts.py
+++ b/src/pipecat/services/resembleai/tts.py
@@ -409,7 +409,9 @@ class ResembleAITTSService(WebsocketTTSService):
 
                 await self.push_frame(TTSStoppedFrame(context_id=context_id))
                 await self.stop_all_metrics()
-                await self.push_error(ErrorFrame(error=f"{self} error: {error_name} - {error_msg}"))
+                await self.push_error_frame(
+                    ErrorFrame(error=f"{self} error: {error_name} - {error_msg}")
+                )
 
                 # Check if this is an unrecoverable error (connection-level failure)
                 if status_code in [401, 403]:
diff --git a/src/pipecat/services/tts_service.py b/src/pipecat/services/tts_service.py
index f386b5bcb..5cc4a4b45 100644
--- a/src/pipecat/services/tts_service.py
+++ b/src/pipecat/services/tts_service.py
@@ -1174,16 +1174,18 @@ class TTSService(AIService):
         logger.trace(f"{self} created audio context {context_id}")
 
     async def append_to_audio_context(
-        self, context_id: str, frame: Frame | _WordTimestampEntry | None
+        self, context_id: str | None, frame: Frame | _WordTimestampEntry | None
     ):
         """Append a frame or word-timestamp entry to an existing audio context queue.
 
-        Passing ``None`` signals end-of-context (used by remove_audio_context to mark
-        the queue for deletion). If the context no longer exists but the context_id
+        Passing a ``frame`` of ``None`` signals end-of-context (used by remove_audio_context
+        to mark the queue for deletion). If the context no longer exists but the context_id
         matches the active turn, the context is transparently recreated before appending.
 
         Args:
-            context_id: The context to append to.
+            context_id: The context to append to. ``None`` is accepted as a no-op
+                (with a debug log) so callers can pass through values from
+                ``get_active_audio_context_id()`` without an explicit guard.
             frame: The frame, word-timestamp entry, or ``None`` (end-of-context sentinel)
                 to append.
         """
diff --git a/src/pipecat/services/websocket_service.py b/src/pipecat/services/websocket_service.py
index 2e6040ead..d7d3cd505 100644
--- a/src/pipecat/services/websocket_service.py
+++ b/src/pipecat/services/websocket_service.py
@@ -42,7 +42,7 @@ class WebsocketService(ABC):
             reconnect_on_error: Whether to automatically reconnect on connection errors.
             **kwargs: Additional arguments (unused, for compatibility).
         """
-        self._websocket: websockets.WebSocketClientProtocol | None = None
+        self._websocket: websockets.WebSocketClientProtocol | None = None  # pyright: ignore[reportAttributeAccessIssue]
         self._reconnect_on_error = reconnect_on_error
         self._reconnect_in_progress: bool = False
         self._disconnecting: bool = False
diff --git a/src/pipecat/services/xtts/tts.py b/src/pipecat/services/xtts/tts.py
index d323e9b67..0d1a068f7 100644
--- a/src/pipecat/services/xtts/tts.py
+++ b/src/pipecat/services/xtts/tts.py
@@ -214,7 +214,11 @@ class XTTSService(TTSService):
             logger.error(f"{self} no studio speakers available")
             return
 
-        embeddings = self._studio_speakers[assert_given(self._settings.voice)]
+        voice = assert_given(self._settings.voice)
+        if voice is None:
+            yield ErrorFrame(error="XTTS voice must be specified")
+            return
+        embeddings = self._studio_speakers[voice]
 
         url = self._base_url + "/tts_stream"