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2026-07-13 13:39:38 +08:00

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3.4 KiB
Python

from pathlib import Path
from dotenv import load_dotenv
from llama_index.core import (
SimpleDirectoryReader,
StorageContext,
VectorStoreIndex,
load_index_from_storage,
)
from llama_index.core.schema import MetadataMode
from livekit.agents import (
Agent,
AgentServer,
AgentSession,
AutoSubscribe,
JobContext,
cli,
llm,
)
from livekit.agents.voice.agent import ModelSettings
from livekit.plugins import deepgram, openai
load_dotenv()
# check if storage already exists
THIS_DIR = Path(__file__).parent
PERSIST_DIR = THIS_DIR / "retrieval-engine-storage"
if not PERSIST_DIR.exists():
# load the documents and create the index
documents = SimpleDirectoryReader(THIS_DIR / "data").load_data()
index = VectorStoreIndex.from_documents(documents)
# store it for later
index.storage_context.persist(persist_dir=PERSIST_DIR)
else:
# load the existing index
storage_context = StorageContext.from_defaults(persist_dir=PERSIST_DIR)
index = load_index_from_storage(storage_context)
class RetrievalAgent(Agent):
def __init__(self, index: VectorStoreIndex):
super().__init__(
instructions=(
"You are a voice assistant created by LiveKit. Your interface "
"with users will be voice. You should use short and concise "
"responses, and avoiding usage of unpronouncable punctuation."
),
stt=deepgram.STT(),
llm=openai.LLM(),
tts=openai.TTS(),
)
self.index = index
async def llm_node(
self,
chat_ctx: llm.ChatContext,
tools: list[llm.FunctionTool],
model_settings: ModelSettings,
):
user_msg = chat_ctx.items[-1]
assert isinstance(user_msg, llm.ChatMessage) and user_msg.role == "user"
user_query = user_msg.text_content
assert user_query is not None
retriever = self.index.as_retriever()
nodes = await retriever.aretrieve(user_query)
instructions = "Context that might help answer the user's question:"
for node in nodes:
node_content = node.get_content(metadata_mode=MetadataMode.LLM)
instructions += f"\n\n{node_content}"
# update the instructions for this turn, you may use some different methods
# to inject the context into the chat_ctx that fits the LLM you are using
system_msg = chat_ctx.items[0]
if isinstance(system_msg, llm.ChatMessage) and system_msg.role == "system":
# TODO(long): provide an api to update the instructions of chat_ctx
system_msg.content.append(instructions)
else:
chat_ctx.items.insert(0, llm.ChatMessage(role="system", content=[instructions]))
preview = instructions[:100].replace("\n", "\\n")
print(f"update instructions: {preview}...")
# update the instructions for agent
# await self.update_instructions(instructions)
return Agent.default.llm_node(self, chat_ctx, tools, model_settings)
server = AgentServer()
@server.rtc_session()
async def entrypoint(ctx: JobContext):
await ctx.connect(auto_subscribe=AutoSubscribe.AUDIO_ONLY)
agent = RetrievalAgent(index)
session = AgentSession()
await session.start(agent=agent, room=ctx.room)
await session.say("Hey, how can I help you today?", allow_interruptions=False)
if __name__ == "__main__":
cli.run_app(server)