feat: better interrupt strategies (#479)

* chore: drain active calls before rolling updates

* Use provisional VAD interruption strategy

* feat: wire provisional VAD configuration

* chore: refactor user turn strategies

* chore: bump pipecat

api/services/pipecat/run_pipeline.py

@@ -80,7 +80,8 @@ from pipecat.turns.user_mute import (
 )
 from pipecat.turns.user_start import (
     ExternalUserTurnStartStrategy,
-    TranscriptionUserTurnStartStrategy,
+    MinWordsUserTurnStartStrategy,
+    ProvisionalVADUserTurnStartStrategy,
 )
 from pipecat.turns.user_start.vad_user_turn_start_strategy import (
     VADUserTurnStartStrategy,
@@ -99,6 +100,10 @@ ensure_tracing()
 
 DEFAULT_USER_TURN_STOP_TIMEOUT = 5.0
 EXTERNAL_TURN_USER_STOP_TIMEOUT = 30.0
+DEFAULT_TURN_START_STRATEGY = "default"
+DEFAULT_TURN_START_MIN_WORDS = 3
+DEFAULT_PROVISIONAL_VAD_PAUSE_SECS = 1.5
+DEFAULT_SMART_TURN_STOP_SECS = 2.0
 
 
 def _resolve_user_turn_stop_timeout(
@@ -111,6 +116,80 @@ def _resolve_user_turn_stop_timeout(
     return DEFAULT_USER_TURN_STOP_TIMEOUT
 
 
+def _resolve_turn_start_min_words(run_configs: dict) -> int:
+    return max(
+        1,
+        int(run_configs.get("turn_start_min_words", DEFAULT_TURN_START_MIN_WORDS)),
+    )
+
+
+def _resolve_provisional_vad_pause_secs(run_configs: dict) -> float:
+    return max(
+        0.1,
+        float(
+            run_configs.get(
+                "provisional_vad_pause_secs", DEFAULT_PROVISIONAL_VAD_PAUSE_SECS
+            )
+        ),
+    )
+
+
+def _create_non_realtime_user_turn_start_strategies(
+    run_configs: dict, *, uses_external_turns: bool
+):
+    """Return user turn start strategies for non-realtime pipelines."""
+
+    turn_start_strategy = run_configs.get(
+        "turn_start_strategy", DEFAULT_TURN_START_STRATEGY
+    )
+
+    if turn_start_strategy == "min_words":
+        return [
+            MinWordsUserTurnStartStrategy(
+                min_words=_resolve_turn_start_min_words(run_configs)
+            )
+        ]
+
+    if turn_start_strategy == "provisional_vad":
+        return [
+            ProvisionalVADUserTurnStartStrategy(
+                pause_secs=_resolve_provisional_vad_pause_secs(run_configs)
+            )
+        ]
+
+    if uses_external_turns:
+        # The STT emits its own turn boundaries and owns interruptions. Local
+        # VAD is deliberately kept out of the default start strategies: it would
+        # win the race on raw voice activity and start the turn before the STT
+        # confirms a real turn.
+        return [ExternalUserTurnStartStrategy(enable_interruptions=True)]
+
+    return [VADUserTurnStartStrategy()]
+
+
+def _create_non_realtime_user_turn_stop_strategies(
+    run_configs: dict, *, uses_external_turns: bool
+):
+    """Return user turn stop strategies for non-realtime pipelines."""
+
+    if uses_external_turns:
+        return [ExternalUserTurnStopStrategy()]
+
+    if run_configs.get("turn_stop_strategy") == "turn_analyzer":
+        smart_turn_params = SmartTurnParams(
+            stop_secs=run_configs.get(
+                "smart_turn_stop_secs", DEFAULT_SMART_TURN_STOP_SECS
+            )
+        )
+        return [
+            TurnAnalyzerUserTurnStopStrategy(
+                turn_analyzer=LocalSmartTurnAnalyzerV3(params=smart_turn_params)
+            )
+        ]
+
+    return [SpeechTimeoutUserTurnStopStrategy()]
+
+
 def _create_realtime_user_turn_config(provider: str):
     """Return user turn strategies and optional local VAD for realtime providers."""
 
@@ -461,8 +540,6 @@ async def _run_pipeline_impl(
     # Extract configurations from the version's workflow_configurations
     max_call_duration_seconds = 300  # Default 5 minutes
     max_user_idle_timeout = 10.0  # Default 10 seconds
-    smart_turn_stop_secs = 2.0  # Default 2 seconds for incomplete turn timeout
-    turn_stop_strategy = "transcription"  # Default to transcription-based detection
     keyterms = None  # Dictionary words for STT boosting
 
     if run_configs:
@@ -472,12 +549,6 @@ async def _run_pipeline_impl(
         if "max_user_idle_timeout" in run_configs:
             max_user_idle_timeout = run_configs["max_user_idle_timeout"]
 
-        if "smart_turn_stop_secs" in run_configs:
-            smart_turn_stop_secs = run_configs["smart_turn_stop_secs"]
-
-        if "turn_stop_strategy" in run_configs:
-            turn_stop_strategy = run_configs["turn_stop_strategy"]
-
         if "dictionary" in run_configs:
             dictionary = run_configs["dictionary"]
             if dictionary and isinstance(dictionary, str):
@@ -734,37 +805,27 @@ async def _run_pipeline_impl(
         # follows those external signals. Other models use configurable turn
         # detection.
         uses_external_turns = stt_uses_external_turns(user_config)
-        if uses_external_turns:
-            user_turn_strategies = UserTurnStrategies(
-                start=[
-                    VADUserTurnStartStrategy(),
-                    ExternalUserTurnStartStrategy(enable_interruptions=True),
-                ],
-                stop=[ExternalUserTurnStopStrategy()],
-            )
-        elif turn_stop_strategy == "turn_analyzer":
-            # Smart Turn Analyzer: best for longer responses with natural pauses
-            smart_turn_params = SmartTurnParams(stop_secs=smart_turn_stop_secs)
-            user_turn_strategies = UserTurnStrategies(
-                start=[
-                    VADUserTurnStartStrategy(),
-                    TranscriptionUserTurnStartStrategy(),
-                ],
-                stop=[
-                    TurnAnalyzerUserTurnStopStrategy(
-                        turn_analyzer=LocalSmartTurnAnalyzerV3(params=smart_turn_params)
-                    )
-                ],
-            )
-        else:
-            # Transcription-based (default): best for short 1-2 word responses
-            user_turn_strategies = UserTurnStrategies(
-                start=[
-                    VADUserTurnStartStrategy(),
-                    TranscriptionUserTurnStartStrategy(),
-                ],
-                stop=[SpeechTimeoutUserTurnStopStrategy()],
-            )
+        user_turn_start_strategies = _create_non_realtime_user_turn_start_strategies(
+            run_configs,
+            uses_external_turns=uses_external_turns,
+        )
+        turn_start_strategy = run_configs.get(
+            "turn_start_strategy", DEFAULT_TURN_START_STRATEGY
+        )
+        logger.info(
+            f"[run {workflow_run_id}] Non-realtime interrupt strategy "
+            f"requested={turn_start_strategy} "
+            f"uses_external_turns={uses_external_turns}"
+        )
+
+        user_turn_stop_strategies = _create_non_realtime_user_turn_stop_strategies(
+            run_configs,
+            uses_external_turns=uses_external_turns,
+        )
+        user_turn_strategies = UserTurnStrategies(
+            start=user_turn_start_strategies,
+            stop=user_turn_stop_strategies,
+        )
 
     user_turn_stop_timeout = _resolve_user_turn_stop_timeout(
         run_configs,

api/services/pipecat/service_factory.py

@@ -197,6 +197,7 @@ def create_stt_service(
         return OpenAISTTService(
             api_key=user_config.stt.api_key,
             settings=OpenAISTTSettings(model=user_config.stt.model),
+            should_interrupt=False,  # Let UserAggregator own interruption confirmation.
             **kwargs,
         )
     elif user_config.stt.provider == ServiceProviders.GOOGLE.value: