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pipecat/examples/multi-task/local-handoff/local-handoff-two-agents-tts.py
Aleix Conchillo Flaqué 7c4294b7f6 Add local-handoff-two-agents-tts example
Variant of the local handoff example with per-task TTS voices.
Each child task wraps the LLM with its own `CartesiaTTSService`
in a custom pipeline override, so the main task has no TTS and
audio comes from whichever child is active over the bus.
2026-05-21 10:12:51 -07:00

269 lines
8.8 KiB
Python

#
# Copyright (c) 2026, Daily
#
# SPDX-License-Identifier: BSD 2-Clause License
#
"""Two LLM tasks with per-task TTS voices.
Same shape as ``local-handoff-two-agents.py``, but each child task
runs its own TTS with a distinct voice. The main task has no TTS —
audio comes from the child tasks via the bus and is played by the
main task's transport. Tasks announce the transfer ("let me connect
you with...") before handing off.
Architecture::
Main task (no TTS):
transport.in → STT → user_agg → BusBridge → transport.out → assistant_agg
Child task (with TTS):
bridge_in → LLM → TTS → bridge_out
Requirements:
- OPENAI_API_KEY
- DEEPGRAM_API_KEY
- CARTESIA_API_KEY
- DAILY_API_KEY (for Daily transport)
"""
import os
from dotenv import load_dotenv
from loguru import logger
from pipecat.audio.vad.silero import SileroVADAnalyzer
from pipecat.bus import BusBridgeProcessor
from pipecat.pipeline.pipeline import Pipeline
from pipecat.pipeline.runner import PipelineRunner
from pipecat.pipeline.task import PipelineParams, PipelineTask
from pipecat.processors.aggregators.llm_context import LLMContext
from pipecat.processors.aggregators.llm_response_universal import (
LLMContextAggregatorPair,
LLMUserAggregatorParams,
)
from pipecat.runner.types import RunnerArguments
from pipecat.runner.utils import create_transport
from pipecat.services.cartesia.tts import CartesiaTTSService
from pipecat.services.deepgram.stt import DeepgramSTTService
from pipecat.services.llm_service import FunctionCallParams
from pipecat.services.openai.llm import OpenAILLMService
from pipecat.tasks.llm import LLMTask, LLMTaskActivationArgs, tool
from pipecat.transports.base_transport import BaseTransport, TransportParams
from pipecat.transports.daily.transport import DailyParams
load_dotenv(override=True)
MAIN_NAME = "acme"
transport_params = {
"daily": lambda: DailyParams(
audio_in_enabled=True,
audio_out_enabled=True,
),
"webrtc": lambda: TransportParams(
audio_in_enabled=True,
audio_out_enabled=True,
),
}
class AcmeTTSTask(LLMTask):
"""Child task with its own LLM + TTS, bridged to the main task.
Each child wraps the standard ``Pipeline([llm])`` with an extra
TTS processor so audio is produced locally by each child and
shipped to the main task over the bus.
"""
def __init__(self, name: str, *, llm: OpenAILLMService, voice_id: str):
"""Initialize the child task.
Args:
name: Unique task name.
llm: The LLM service for this child.
voice_id: Cartesia voice id for this child's TTS.
"""
tts = CartesiaTTSService(
api_key=os.environ["CARTESIA_API_KEY"],
settings=CartesiaTTSService.Settings(voice=voice_id),
)
super().__init__(
name,
llm=llm,
pipeline=Pipeline([llm, tts]),
bridged=(),
)
@tool(cancel_on_interruption=False)
async def transfer_to_agent(self, params: FunctionCallParams, agent: str, reason: str):
"""Transfer the user to another agent.
Args:
agent (str): The agent to transfer to (e.g. 'greeter', 'support').
reason (str): Why the user is being transferred.
"""
logger.info(f"Task '{self.name}': transferring to '{agent}' ({reason})")
await self.handoff_to(
agent,
messages=[
{
"role": "developer",
"content": f"Tell the user about the transfer ({reason}).",
}
],
activation_args=LLMTaskActivationArgs(
messages=[{"role": "developer", "content": reason}],
),
result_callback=params.result_callback,
)
@tool
async def end_conversation(self, params: FunctionCallParams, reason: str):
"""End the conversation when the user says goodbye.
Args:
reason (str): Why the conversation is ending.
"""
logger.info(f"Task '{self.name}': ending conversation ({reason})")
await self.end(
reason=reason,
messages=[{"role": "developer", "content": reason}],
result_callback=params.result_callback,
)
def _build_greeter() -> AcmeTTSTask:
"""Greeter: routes the user to support when they pick a product."""
llm = OpenAILLMService(
api_key=os.environ["OPENAI_API_KEY"],
settings=OpenAILLMService.Settings(
system_instruction=(
"You are a friendly greeter for Acme Corp. The available products "
"are: the Acme Rocket Boots, the Acme Invisible Paint, and the Acme "
"Tornado Kit. Ask which one they'd like to learn more about. "
"When the user picks a product or asks a question about one, "
"call the transfer_to_agent tool with agent 'support'. "
"Do not answer product questions yourself. If the user says goodbye, "
"call the end_conversation tool. Keep responses brief — this is a "
"voice conversation."
),
),
)
return AcmeTTSTask(
"greeter",
llm=llm,
voice_id="9626c31c-bec5-4cca-baa8-f8ba9e84c8bc", # Jacqueline
)
def _build_support() -> AcmeTTSTask:
"""Support: answers product questions, can hand back to the greeter."""
llm = OpenAILLMService(
api_key=os.environ["OPENAI_API_KEY"],
settings=OpenAILLMService.Settings(
system_instruction=(
"You are a support agent for Acme Corp. You know about three "
"products: Acme Rocket Boots (jet-powered boots, $299, run up "
"to 60 mph), Acme Invisible Paint (makes anything invisible for "
"24 hours, $49 per can), and Acme Tornado Kit (portable tornado "
"generator, $199, batteries included). Answer the user's questions "
"about these products. If the user wants to browse other products "
"or start over, call the transfer_to_agent tool with agent "
"'greeter'. If the user says goodbye, call the end_conversation "
"tool. Keep responses brief — this is a voice conversation."
),
),
)
return AcmeTTSTask(
"support",
llm=llm,
voice_id="a167e0f3-df7e-4d52-a9c3-f949145efdab", # Blake
)
async def run_bot(transport: BaseTransport, runner_args: RunnerArguments):
logger.info("Starting two-agents-with-tts bot")
runner = PipelineRunner(handle_sigint=runner_args.handle_sigint)
stt = DeepgramSTTService(api_key=os.environ["DEEPGRAM_API_KEY"])
context = LLMContext()
aggregators = LLMContextAggregatorPair(
context,
user_params=LLMUserAggregatorParams(vad_analyzer=SileroVADAnalyzer()),
)
# The main task has no TTS. Audio comes from the children over
# the bus; the main bridge tees user context out and pushes
# incoming audio/text frames back into the local pipeline.
bridge = BusBridgeProcessor(
bus=runner.bus,
task_name=MAIN_NAME,
name=f"{MAIN_NAME}::BusBridge",
)
pipeline = Pipeline(
[
transport.input(),
stt,
aggregators.user(),
bridge,
transport.output(),
aggregators.assistant(),
]
)
task = PipelineTask(
pipeline,
name=MAIN_NAME,
params=PipelineParams(
enable_metrics=True,
enable_usage_metrics=True,
),
idle_timeout_secs=runner_args.pipeline_idle_timeout_secs,
)
await runner.spawn(_build_greeter())
await runner.spawn(_build_support())
@transport.event_handler("on_client_connected")
async def on_client_connected(transport, client):
logger.info("Client connected")
await task.activate_task(
"greeter",
args=LLMTaskActivationArgs(
messages=[
{
"role": "developer",
"content": (
"Welcome the user to Acme Corp, mention the available products "
"and ask how you can help."
),
},
],
),
)
@transport.event_handler("on_client_disconnected")
async def on_client_disconnected(transport, client):
logger.info("Client disconnected")
await task.cancel()
await runner.run(task)
async def bot(runner_args: RunnerArguments):
"""Main bot entry point compatible with Pipecat Cloud."""
transport = await create_transport(runner_args, transport_params)
await run_bot(transport, runner_args)
if __name__ == "__main__":
from pipecat.runner.run import main
main()