fix: clear 10 more services from pyright ignore list

A third pass over low-error-count files in the ignore list. Drops 10
files (67 → 57) and full-pyright errors from 555 → 525. Default
pyright stays clean.

Optional access guards (4 files). The same fix shape as 9e9b1f39e:
a receiver typed `X | None` accessed without a guard, fixed with a
local-var capture or an early return.

- `mistral/stt.py`: `_connection.send_audio` could crash if
  `_connect()` swallowed an exception and left `_connection` unset;
  drop the audio chunk with a warning instead. `_receive_events`
  iterating `_connection.events()` got the same defensive narrowing.
- `deepgram/flux/stt.py`: `_websocket_url` is set in `_connect`
  before `_connect_websocket` is called, but pyright doesn't track
  that across methods — assert at the use site. `websocket.response`
  is `Response | None` in the websockets stubs even though it's
  always populated post-handshake; guarded with a fallback.
- `audio/filters/rnnoise_filter.py`: the module-level import sets
  `RNNoise` to `None` if `pyrnnoise` isn't installed; raise
  `ImportError` explicitly instead of relying on the existing try-
  block to catch the `None(...)` call. Also gated `filter()` with
  `or self._rnnoise is None` so pyright sees the narrowing.
- `transports/smallwebrtc/request_handler.py`: `get_answer()`
  legitimately returns `None`; raise instead of crashing on three
  subscript accesses.

`TTSService` `audio-context` API tightening. Mirroring the
`append_to_audio_context` fix from the previous batch:
`remove_audio_context` was typed `str` but is called with `str | None`
from `get_active_audio_context_id()` results. Widened to `str | None`
and the `None` handling lives in the function body (early debug log
+ return) — matching `append_to_audio_context`'s shape.
`audio_context_available` keeps its narrow `str` signature; asking
"is `None` available?" isn't a meaningful question (`_audio_contexts`
is `dict[str, asyncio.Queue]`). The internal call site in
`on_turn_context_completed` narrows `_turn_context_id` explicitly
before passing it. Side effect: deepgram/tts.py's L307 error clears
without local changes.

`deepgram/tts.py` (4 errors → 0): the same `push_error(ErrorFrame(...))`
latent bug we fixed in resembleai earlier in this PR — `push_error`
takes a string; there's a separate `push_error_frame` for frames.
Two sites switched. The Optional `_websocket.response` access is
guarded the same way as deepgram/flux/stt.py. The `remove_audio_context`
error was cleared by the tightening above.

`aws/utils.py` (3 errors → 0): `AWSTranscribePresignedURL` declared
`session_token: str` but the dict source is `str | None` (AWS
supports long-term IAM creds without a session token). Same for
`vocabulary_name`/`vocabulary_filter_name` on `get_request_url`,
which were typed `str = ""` even though the body uses truthy checks
to skip them. Widened to `str | None = None` — matches actual
runtime semantics.

`audio/dtmf/utils.py` (2 errors → 0): `files("...").joinpath(...)`
returns a `Traversable`, but `aiofiles.open` wants a real path. For
regular pip installs this worked in practice (Traversable was a
`Path`), but it would fail for zipped distributions (zipapp,
zipimport) where the resource isn't on disk. Wrapped in
`importlib.resources.as_file(...)` — the canonical bridge that
extracts to a temp file when the resource isn't already on the
filesystem. Validated end-to-end: regular install still reads bytes;
ad-hoc zipapp test confirmed `as_file` extracts the resource and
returns a real Path.

`openai/image.py` (2 errors → 0): the `size` arg to
`images.generate` is `Literal[...] | None` in the SDK but our
settings field is `str | None`. Mirrored the `groq/tts.py`
hint-not-constraint pattern from the previous batch: defined a
module-level `OpenAIImageSize = Literal[...]` alias with a comment
attributing the upstream symbol and documenting the cast contract
(callers can pass any string; invalid values surface as an OpenAI
API error). Also guarded `image.data[0]` (response.data is
`list[Image] | None`).

`processors/frameworks/{langchain,strands_agents}.py` (4 + 4 → 0):
both processors do `messages[-1]["content"]` on a value typed
`LLMStandardMessage | LLMSpecificMessage` (the latter is a dataclass,
not a dict, so `__getitem__` errors). Historically these only
handled plain-text user messages, so the fix is two explicit guards
(skip if the last message isn't a dict; skip if `content` isn't a
string) plus a TODO noting that other shapes (multi-modal content,
provider-specific messages) aren't supported yet. langchain's
`__get_token_value` also got a small fix where `AIMessageChunk.content`
is `str | list[parts]` but the function declares `-> str`; stringify
the list case. strands_agents' surfaced two unrelated narrows: a
`graph_exit_node: str | None` arg gated by an `__init__`-time assert,
and `agent.stream_async` reached only when we're not in graph mode.

Files dropped from the ignore list (67 → 57):
audio/dtmf/utils.py, audio/filters/rnnoise_filter.py,
processors/frameworks/langchain.py,
processors/frameworks/strands_agents.py, services/aws/utils.py,
services/deepgram/flux/stt.py, services/deepgram/tts.py,
services/mistral/stt.py, services/openai/image.py,
transports/smallwebrtc/request_handler.py.

pyrightconfig.json

@@ -6,30 +6,23 @@
   "exclude": ["**/*_pb2.py", "**/__pycache__"],
   "ignore": [
     "tests",
-    "src/pipecat/audio/dtmf/utils.py",
     "src/pipecat/audio/filters/aic_filter.py",
     "src/pipecat/audio/filters/krisp_viva_filter.py",
-    "src/pipecat/audio/filters/rnnoise_filter.py",
     "src/pipecat/audio/turn/smart_turn/local_smart_turn_v2.py",
     "src/pipecat/audio/turn/smart_turn/local_smart_turn_v3.py",
     "src/pipecat/audio/vad/silero.py",
     "src/pipecat/processors/aggregators/llm_response_universal.py",
     "src/pipecat/processors/frame_processor.py",
-    "src/pipecat/processors/frameworks/langchain.py",
     "src/pipecat/processors/frameworks/rtvi/observer.py",
-    "src/pipecat/processors/frameworks/strands_agents.py",
     "src/pipecat/services/anthropic/llm.py",
     "src/pipecat/services/aws/llm.py",
     "src/pipecat/services/aws/nova_sonic/llm.py",
     "src/pipecat/services/aws/sagemaker/bidi_client.py",
-    "src/pipecat/services/aws/utils.py",
     "src/pipecat/services/azure/tts.py",
     "src/pipecat/services/deepgram/flux/base.py",
     "src/pipecat/services/deepgram/flux/sagemaker/stt.py",
-    "src/pipecat/services/deepgram/flux/stt.py",
     "src/pipecat/services/deepgram/sagemaker/stt.py",
     "src/pipecat/services/deepgram/sagemaker/tts.py",
-    "src/pipecat/services/deepgram/tts.py",
     "src/pipecat/services/elevenlabs/tts.py",
     "src/pipecat/services/google/gemini_live/llm.py",
     "src/pipecat/services/google/gemini_live/vertex/llm.py",
@@ -41,13 +34,11 @@
     "src/pipecat/services/inworld/realtime/llm.py",
     "src/pipecat/services/llm_service.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/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/realtime/llm.py",
     "src/pipecat/services/openai/stt.py",
     "src/pipecat/services/rime/tts.py",
@@ -66,7 +57,6 @@
     "src/pipecat/transports/lemonslice/transport.py",
     "src/pipecat/transports/livekit/transport.py",
     "src/pipecat/transports/smallwebrtc/connection.py",
-    "src/pipecat/transports/smallwebrtc/request_handler.py",
     "src/pipecat/transports/smallwebrtc/transport.py",
     "src/pipecat/transports/tavus/transport.py",
     "src/pipecat/transports/websocket/client.py",

src/pipecat/audio/dtmf/utils.py

@@ -14,7 +14,7 @@ in-memory after first load to improve performance on subsequent accesses.
 import asyncio
 import io
 import wave
-from importlib.resources import files
+from importlib.resources import as_file, files
 
 import aiofiles
 
@@ -52,10 +52,12 @@ async def load_dtmf_audio(button: KeypadEntry, *, sample_rate: int = 8000) -> by
             __DTMF_RESAMPLER__ = create_file_resampler()
 
         dtmf_file_name = __DTMF_FILE_NAME.get(button, f"dtmf-{button.value}.wav")
-        dtmf_file_path = files("pipecat.audio.dtmf").joinpath(dtmf_file_name)
-
-        async with aiofiles.open(dtmf_file_path, "rb") as f:
-            data = await f.read()
+        # `as_file` materialises the resource as a real filesystem `Path`,
+        # which aiofiles can open. (For installed packages this is just the
+        # bundled file; for zipped distributions it would extract to a temp.)
+        with as_file(files("pipecat.audio.dtmf").joinpath(dtmf_file_name)) as dtmf_file_path:
+            async with aiofiles.open(dtmf_file_path, "rb") as f:
+                data = await f.read()
 
         with io.BytesIO(data) as buffer:
             with wave.open(buffer, "rb") as wf:

src/pipecat/audio/filters/rnnoise_filter.py

@@ -60,7 +60,12 @@ class RNNoiseFilter(BaseAudioFilter):
         self._sample_rate = sample_rate
 
         try:
-            # RNNoise always requires 48kHz
+            # The module-level import sets `RNNoise` to `None` if pyrnnoise
+            # isn't installed; raise instead of calling `None(...)` so the
+            # except clause handles it cleanly.
+            if RNNoise is None:
+                raise ImportError("pyrnnoise is not installed")
+            # RNNoise always requires 48kHz.
             self._rnnoise = RNNoise(sample_rate=48000)
             self._rnnoise_ready = True
         except Exception as e:
@@ -107,7 +112,7 @@ class RNNoiseFilter(BaseAudioFilter):
         Returns:
             Noise-suppressed audio data as bytes.
         """
-        if not self._rnnoise_ready or not self._filtering:
+        if not self._rnnoise_ready or not self._filtering or self._rnnoise is None:
             return audio
 
         # Resample input if needed

src/pipecat/processors/frameworks/langchain.py

@@ -67,9 +67,20 @@ class LangchainProcessor(FrameProcessor):
             # The last one by the human is the one we want to send to the LLM.
             logger.debug(f"Got transcription frame {frame}")
             messages = frame.context.get_messages()
-            text: str = messages[-1]["content"]
+            # Historically this processor has only handled plain-text user
+            # messages; the guards below make that contract explicit for the
+            # type checker. TODO: maybe handle other message shapes (provider-
+            # specific messages, multi-modal content lists, etc.).
+            last_message = messages[-1] if messages else None
+            if not isinstance(last_message, dict):
+                await self.push_frame(frame, direction)
+                return
+            content = last_message.get("content")
+            if not isinstance(content, str):
+                await self.push_frame(frame, direction)
+                return
 
-            await self._ainvoke(text.strip())
+            await self._ainvoke(content.strip())
         else:
             await self.push_frame(frame, direction)
 
@@ -87,7 +98,10 @@ class LangchainProcessor(FrameProcessor):
             case str():
                 return text
             case AIMessageChunk():
-                return text.content
+                # `content` is `str | list[...]` (multi-modal); stringify if
+                # it's a list, since downstream consumers want plain text.
+                content = text.content
+                return content if isinstance(content, str) else str(content)
             case _:
                 return ""
 

src/pipecat/processors/frameworks/strands_agents.py

@@ -71,9 +71,15 @@ class StrandsAgentsProcessor(FrameProcessor):
         await super().process_frame(frame, direction)
         if isinstance(frame, LLMContextFrame):
             messages = frame.context.get_messages()
-            if messages:
-                last_message = messages[-1]
-                await self._ainvoke(str(last_message["content"]).strip())
+            # Historically this processor has only handled plain-text user
+            # messages; the guards below make that contract explicit for the
+            # type checker. TODO: handle other message shapes (provider-
+            # specific messages, multi-modal content lists, etc.).
+            last_message = messages[-1] if messages else None
+            if isinstance(last_message, dict):
+                content = last_message.get("content")
+                if isinstance(content, str):
+                    await self._ainvoke(content.strip())
         else:
             await self.push_frame(frame, direction)
 
@@ -91,6 +97,9 @@ class StrandsAgentsProcessor(FrameProcessor):
             await self.start_ttfb_metrics()
 
             if self.graph:
+                # `__init__` asserts `graph_exit_node` is set whenever `graph`
+                # is, so this can't be None here.
+                assert self.graph_exit_node is not None
                 # Graph does not stream; await full result then emit assistant text
                 graph_result = await self.graph.invoke_async(text)
                 if ttfb_tracking:
@@ -115,6 +124,9 @@ class StrandsAgentsProcessor(FrameProcessor):
                 except Exception as parse_err:
                     logger.warning(f"Failed to extract messages from GraphResult: {parse_err}")
             else:
+                # `__init__` asserts at least one of `agent`/`graph` is set,
+                # and we're in the `not self.graph` branch.
+                assert self.agent is not None
                 # Agent supports streaming events via async iterator
                 async for event in self.agent.stream_async(text):
                     # Push to TTS service

src/pipecat/services/aws/utils.py

@@ -92,14 +92,18 @@ class AWSTranscribePresignedURL:
     """
 
     def __init__(
-        self, access_key: str, secret_key: str, session_token: str, region: str = "us-east-1"
+        self,
+        access_key: str,
+        secret_key: str,
+        session_token: str | None,
+        region: str = "us-east-1",
     ):
         """Initialize the presigned URL generator.
 
         Args:
             access_key: AWS access key ID.
             secret_key: AWS secret access key.
-            session_token: AWS session token for temporary credentials.
+            session_token: AWS session token for temporary credentials (optional).
             region: AWS region for the service. Defaults to "us-east-1".
         """
         self.access_key = access_key
@@ -129,8 +133,8 @@ class AWSTranscribePresignedURL:
         sample_rate: int,
         language_code: str = "",
         media_encoding: str = "pcm",
-        vocabulary_name: str = "",
-        vocabulary_filter_name: str = "",
+        vocabulary_name: str | None = None,
+        vocabulary_filter_name: str | None = None,
         show_speaker_label: bool = False,
         enable_channel_identification: bool = False,
         number_of_channels: int = 1,

src/pipecat/services/deepgram/flux/stt.py

@@ -299,14 +299,19 @@ class DeepgramFluxSTTService(DeepgramFluxSTTBase, WebsocketService):
 
             self._connection_established_event.clear()
             self._user_is_speaking = False
-            self._websocket = await websocket_connect(
+            # `_connect` sets `_websocket_url` before calling us; the assert
+            # narrows for pyright.
+            assert self._websocket_url is not None
+            websocket = await websocket_connect(
                 self._websocket_url,
                 additional_headers={"Authorization": f"Token {self._api_key}"},
             )
+            self._websocket = websocket
 
-            headers = {
-                k: v for k, v in self._websocket.response.headers.items() if k.startswith("dg-")
-            }
+            # `response` is populated after the handshake completes (which it
+            # has, since `websocket_connect` already returned).
+            response_headers = websocket.response.headers if websocket.response else {}
+            headers = {k: v for k, v in response_headers.items() if k.startswith("dg-")}
             logger.debug(f'{self}: Websocket connection initialized: {{"headers": {headers}}}')
 
             # Creating the receiver task

src/pipecat/services/deepgram/tts.py

@@ -232,17 +232,19 @@ class DeepgramTTSService(WebsocketTTSService):
 
             headers = {"Authorization": f"Token {self._api_key}"}
 
-            self._websocket = await websocket_connect(url, additional_headers=headers)
+            websocket = await websocket_connect(url, additional_headers=headers)
+            self._websocket = websocket
 
-            headers = {
-                k: v for k, v in self._websocket.response.headers.items() if k.startswith("dg-")
-            }
+            # `response` is populated after the handshake completes (which it
+            # has, since `websocket_connect` already returned).
+            response_headers = websocket.response.headers if websocket.response else {}
+            headers = {k: v for k, v in response_headers.items() if k.startswith("dg-")}
             logger.debug(f'{self}: Websocket connection initialized: {{"headers": {headers}}}')
 
             await self._call_event_handler("on_connected")
         except Exception as e:
             logger.error(f"{self} exception: {e}")
-            await self.push_error(ErrorFrame(error=f"{self} error: {e}"))
+            await self.push_error_frame(ErrorFrame(error=f"{self} error: {e}"))
             self._websocket = None
             await self._call_event_handler("on_connection_error", f"{e}")
 
@@ -258,7 +260,7 @@ class DeepgramTTSService(WebsocketTTSService):
                 await self._websocket.close()
         except Exception as e:
             logger.error(f"{self} exception: {e}")
-            await self.push_error(ErrorFrame(error=f"{self} error: {e}"))
+            await self.push_error_frame(ErrorFrame(error=f"{self} error: {e}"))
         finally:
             self._websocket = None
             await self._call_event_handler("on_disconnected")

src/pipecat/services/mistral/stt.py

@@ -198,6 +198,13 @@ class MistralSTTService(STTService):
         if not self._connection or self._connection.is_closed:
             await self._connect()
 
+        # `_connect` swallows exceptions and may leave `_connection` unset;
+        # drop the audio chunk rather than crashing if reconnect failed.
+        if self._connection is None:
+            logger.warning(f"{self}: dropping audio chunk — Mistral STT not connected")
+            yield None
+            return
+
         await self._connection.send_audio(audio)
         yield None
 
@@ -248,8 +255,13 @@ class MistralSTTService(STTService):
 
     async def _receive_events(self):
         """Background task: iterate connection events and handle them."""
+        # `_connect` started this task only after assigning `_connection`,
+        # so it should not be None here; bail out defensively just in case.
+        connection = self._connection
+        if connection is None:
+            return
         try:
-            async for event in self._connection.events():
+            async for event in connection.events():
                 if isinstance(event, RealtimeTranscriptionSessionCreated):
                     logger.debug(f"{self}: Session created: {event.session}")
                     await self._call_event_handler("on_connected")

src/pipecat/services/openai/image.py

@@ -13,7 +13,7 @@ for creating images from text prompts.
 import io
 from collections.abc import AsyncGenerator
 from dataclasses import dataclass, field
-from typing import Literal
+from typing import Literal, cast
 
 import aiohttp
 from loguru import logger
@@ -28,6 +28,28 @@ from pipecat.frames.frames import (
 from pipecat.services.image_service import ImageGenService
 from pipecat.services.settings import NOT_GIVEN, ImageGenSettings, _NotGiven, assert_given
 
+# Hint set for the `size` argument to `images.generate`. The values mirror the
+# Literal that `openai.resources.images.Images.generate` accepts on its `size`
+# parameter (also visible as the `size` field of
+# `openai.types.image_generate_params.ImageGenerateParams`). The OpenAI SDK
+# does not export this as a named alias, so we redeclare it here.
+#
+# We cast `_settings.image_size` (a plain `str`) to this Literal at the API
+# boundary so callers can still pass any size string (e.g. a newer value the
+# SDK accepts before this list is updated). Invalid values surface as an
+# OpenAI API error at runtime. Keep in sync on a best-effort basis when
+# bumping the openai dep.
+OpenAIImageSize = Literal[
+    "auto",
+    "1024x1024",
+    "1536x1024",
+    "1024x1536",
+    "256x256",
+    "512x512",
+    "1792x1024",
+    "1024x1792",
+]
+
 
 @dataclass
 class OpenAIImageGenSettings(ImageGenSettings):
@@ -116,15 +138,19 @@ class OpenAIImageGenService(ImageGenService):
         """
         logger.debug(f"Generating image from prompt: {prompt}")
 
+        size = cast(OpenAIImageSize | None, assert_given(self._settings.image_size))
         image = await self._client.images.generate(
             prompt=prompt,
             model=assert_given(self._settings.model),
             n=1,
-            size=assert_given(self._settings.image_size),
+            size=size,
         )
 
-        image_url = image.data[0].url
+        if not image.data:
+            yield ErrorFrame("Image generation failed: no data returned")
+            return
 
+        image_url = image.data[0].url
         if not image_url:
             yield ErrorFrame("Image generation failed")
             return

src/pipecat/services/tts_service.py

@@ -612,8 +612,10 @@ class TTSService(AIService):
         """Handle the completion of a turn."""
         # For HTTP services they emit the frames synchronously, so close the audio context here
         # once all frames (including TTSTextFrame above) have been enqueued.
-        if self._is_yielding_frames_synchronously and self.audio_context_available(
-            self._turn_context_id
+        if (
+            self._is_yielding_frames_synchronously
+            and self._turn_context_id is not None
+            and self.audio_context_available(self._turn_context_id)
         ):
             if self._push_stop_frames:
                 await self.append_to_audio_context(
@@ -1206,12 +1208,17 @@ class TTSService(AIService):
         else:
             logger.debug(f"{self} unable to append audio to context {context_id}")
 
-    async def remove_audio_context(self, context_id: str):
+    async def remove_audio_context(self, context_id: str | None):
         """Remove an existing audio context.
 
         Args:
-            context_id: The context to remove.
+            context_id: The context to remove. ``None`` is accepted as a
+                no-op (logged) so callers can pass through values from
+                ``get_active_audio_context_id()`` without an explicit guard.
         """
+        if not context_id:
+            logger.debug(f"{self} unable to remove audio context: no context ID provided")
+            return
         if self.audio_context_available(context_id):
             # We just mark the audio context for deletion by appending
             # None. Once we reach None while handling audio we know we can

src/pipecat/transports/smallwebrtc/request_handler.py

@@ -224,6 +224,8 @@ class SmallWebRTCRequestHandler:
                     )
 
             answer = pipecat_connection.get_answer()
+            if answer is None:
+                raise RuntimeError("SmallWebRTC connection produced no SDP answer")
 
             if self._esp32_mode:
                 from pipecat.runner.utils import smallwebrtc_sdp_munging