From ddf6a418543b02884bea0b73468a1442447de337 Mon Sep 17 00:00:00 2001
From: Mark Backman <mark@daily.co>
Date: Tue, 24 Mar 2026 16:11:35 -0400
Subject: [PATCH 1/3] Add on_end_of_turn event handler to AssemblyAI STT

Fires after the final transcript is pushed in both Pipecat and
AssemblyAI turn detection modes, giving users a reliable hook
that arrives after all transcript frames. Matches the existing
Deepgram Flux on_end_of_turn pattern.
---
 src/pipecat/services/assemblyai/stt.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/pipecat/services/assemblyai/stt.py b/src/pipecat/services/assemblyai/stt.py
index fa723a771..8b273188f 100644
--- a/src/pipecat/services/assemblyai/stt.py
+++ b/src/pipecat/services/assemblyai/stt.py
@@ -129,6 +129,16 @@ class AssemblyAISTTService(WebsocketSTTService):
     Provides real-time speech transcription using AssemblyAI's WebSocket API.
     Supports both interim and final transcriptions with configurable parameters
     for audio processing and connection management.
+
+    Event handlers available (in addition to WebsocketSTTService events):
+
+    - on_end_of_turn(service, transcript): Called when AssemblyAI detects end of turn.
+
+    Example::
+
+        @service.event_handler("on_end_of_turn")
+        async def on_end_of_turn(service, transcript):
+            ...
     """
 
     Settings = AssemblyAISTTSettings
@@ -303,6 +313,8 @@ class AssemblyAISTTService(WebsocketSTTService):
 
         self._user_speaking = False
 
+        self._register_event_handler("on_end_of_turn")
+
     def _configure_pipecat_turn_mode(self, settings: Settings, is_u3_pro: bool):
         """Configure settings for Pipecat turn detection mode.
 
@@ -741,6 +753,7 @@ class AssemblyAISTTService(WebsocketSTTService):
                 )
                 await self._trace_transcription(transcript_text, True, language)
                 await self.stop_processing_metrics()
+                await self._call_event_handler("on_end_of_turn", transcript_text)
             else:
                 await self.push_frame(
                     InterimTranscriptionFrame(
@@ -774,6 +787,7 @@ class AssemblyAISTTService(WebsocketSTTService):
                 # above, so ordering is preserved) and upstream.
                 await self.broadcast_frame(UserStoppedSpeakingFrame)
                 self._user_speaking = False
+                await self._call_event_handler("on_end_of_turn", transcript_text)
             else:
                 await self.push_frame(
                     InterimTranscriptionFrame(

From 6c30371295109740d19a344a15fa188c3aca384c Mon Sep 17 00:00:00 2001
From: Mark Backman <mark@daily.co>
Date: Tue, 24 Mar 2026 16:12:25 -0400
Subject: [PATCH 2/3] Fix Deepgram Flux event handler docstring to match
 implementation

Update documented event signatures to include transcript argument
where the code actually passes it. Remove stale on_speech_started
and on_utterance_end entries that were never registered.
---
 src/pipecat/services/deepgram/flux/stt.py | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/pipecat/services/deepgram/flux/stt.py b/src/pipecat/services/deepgram/flux/stt.py
index 64d4e87b9..c75a092a0 100644
--- a/src/pipecat/services/deepgram/flux/stt.py
+++ b/src/pipecat/services/deepgram/flux/stt.py
@@ -102,16 +102,15 @@ class DeepgramFluxSTTService(WebsocketSTTService):
 
     Event handlers available (in addition to WebsocketSTTService events):
 
-    - on_speech_started(service): Deepgram detected start of speech
-    - on_utterance_end(service): Deepgram detected end of utterance
-    - on_end_of_turn(service): Deepgram detected end of turn (EOT)
-    - on_eager_end_of_turn(service): Deepgram predicted end of turn (EagerEOT)
+    - on_start_of_turn(service, transcript): Deepgram detected start of speech
+    - on_end_of_turn(service, transcript): Deepgram detected end of turn (EOT)
+    - on_eager_end_of_turn(service, transcript): Deepgram predicted end of turn (EagerEOT)
     - on_turn_resumed(service): User resumed speaking after EagerEOT
 
     Example::
 
         @stt.event_handler("on_end_of_turn")
-        async def on_end_of_turn(service):
+        async def on_end_of_turn(service, transcript):
             ...
     """
 

From b66c89210044afc6286da378e791b31240d6c591 Mon Sep 17 00:00:00 2001
From: Mark Backman <mark@daily.co>
Date: Tue, 24 Mar 2026 16:15:00 -0400
Subject: [PATCH 3/3] Add changelog for #4128

---
 changelog/4128.added.md | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog/4128.added.md

diff --git a/changelog/4128.added.md b/changelog/4128.added.md
new file mode 100644
index 000000000..7cbeed91b
--- /dev/null
+++ b/changelog/4128.added.md
@@ -0,0 +1 @@
+- Added `on_end_of_turn` event handler to `AssemblyAISTTService`. This fires after the final transcript is pushed, providing a reliable hook for end-of-turn logic that doesn't race with `TranscriptionFrame`. Works in both Pipecat and AssemblyAI turn detection modes.