tall-cricket-35295
04/03/2026, 5:31 AMtall-airline-16756
04/03/2026, 5:31 AMtall-airline-16756
04/03/2026, 5:31 AMon_enter function.
Short answer:
• on_enter is an agent lifecycle hook and can send messages as the agent (use generate_reply()).
• You cannot make the agent’s on_enter send a message that impersonates or originates from the customer. To send a customer-originated message, you must send it from the customer’s side (frontend or participant connection) using the LiveKit SDK.
What you can do
• If you want the agent to proactively send a message when it becomes active (agent message):
◦ Python example:
async def on_enter(self):
await self.session.generate_reply(
instructions="Greet the user with a warm welcome",
)
• Node/TypeScript example:
async onEnter(): Promise<void> {
this.session.generateReply({
instructions: "Greet the user with a warm welcome",
});
}
• This sends an agent-generated reply (the agent’s voice/identity), not a customer message.
• If you need a message that appears to come from the customer (i.e., a user-originated chat event):
◦ Trigger that from the frontend or the participant connection using the LiveKit SDK — have the client send the chat/message when the agent enters or when you receive an agent event.
◦ Example approach:
i. Agent runs on_enter and emits a signal/event (or the server-side agent stores a flag).
ii. Frontend listens for that event (websocket, signaling, or a server push).
iii. Frontend calls LiveKit SDK to publish the chat/message as the customer participant.
Quick clarifying question
• Do you want the agent to send a message as itself when it enters, or do you specifically need a message that originates from the customer participant? If you tell me which language/SDK you’re using (Python, Node, or browser JS) I can give a short concrete example for your route. Sources: Pipeline nodes and hooks | LiveKit Documentation | Build a salary negotiation coach with a LemonSlice avatar | LiveKit, with interactive elementstall-cricket-35295
04/03/2026, 5:33 AMtall-airline-16756
04/03/2026, 5:34 AMon_enter.
I can help, but I need a bit more detail so I can give a targeted fix. A few quick questions that will narrow this down:
1. Which SDK and language are you using for the agent (Python, Node/TypeScript, browser JS)?
2. Are you using OpenAI’s realtime model as the agent’s LLM inside LiveKit Agents, or are you driving messages directly to OpenAI from your app?
3. What exactly happens when the agent starts? Examples that help:
◦ Does the agent send a different first message than the instructions you passed to generate_reply()?
◦ Does it send multiple messages, or a truncated/garbled message?
◦ Any error logs printed on the server or client when this occurs?
1. Can you paste the minimal on_enter code you’re using (redact any keys/tokens)?
2. Do you want the agent to:
◦ Send a proactive agent message on enter (agent identity), or
◦ Cause the customer participant to send a message (user identity)?
What I can suggest immediately
• If the model is producing unexpected content, try keeping instructions concise and explicit (e.g., “Send exactly: Hello — I’m your agent.”) so the model’s first output is constrained.
• If timing/race conditions seem likely (realtime stream starting before prompt is set), we may need to ensure the session/context is fully initialized before calling generate_reply() in on_enter. Let me know your SDK and I’ll show how to await readiness.
• If you’re trying to emulate a customer message, remember on_enter runs as the agent; pushing a user-originating message must happen from the participant/client side. I can show a pattern where the agent signals the frontend and the frontend publishes the user message.
Send the answers to the questions above or paste the on_enter snippet and any logs you have, and I’ll walk through a specific fix for your realtime setup.
, with interactive elementstall-cricket-35295
04/03/2026, 5:35 AMtall-airline-16756
04/03/2026, 5:35 AMgenerate_reply() in on_enter makes the agent speak something unexpected, and you want the session to start with the customer saying “Hello” instead.
Short answer
• on_enter runs as the agent. generate_reply() always makes the agent speak, so it cannot produce a message that originates from the customer.
• To make the conversation start with a customer-originated “Hello” you must send that message from the participant side (frontend) or simulate a participant message programmatically after the agent session is initialized.
Two practical ways to do this in Python (pick one):
1) Preferred — Frontend sends “Hello” after agent readiness
• Flow:
a. Start the room and agent session.
b. Have the frontend wait until the agent is ready (e.g., after connecting or after receiving a readiness event).
c. Frontend sends the customer message via the LiveKit SDK: localParticipant.sendText("Hello", { topic: 'lk.chat' }).
• Why: This guarantees the message truly originates from the participant and avoids any realtime-model prompt/race issues that make the agent speak unexpectedly.
2) Backend simulation — simulate a participant message in on_enter (useful for testing/automation)
• Implement a short delay to ensure session is fully initialized, then call the session input API to simulate an incoming user message. Example pattern:
import asyncio
async def on_enter(self) -> None:
# Wait for session readiness (adjust delay as needed)
await asyncio.sleep(0.5)
# Simulate a user text message arriving (appears as customer-originated)
self.session.input.text_received(
text="Hello",
participant=self.session.room.local_participant
)
• Notes:
◦ This uses the agent session input system to simulate an lk.chat message. It makes the agent handle “Hello” as if a participant sent it.
◦ Use this only when you cannot or do not want to rely on a real frontend participant. For production, real participant-sent messages are recommended.
Additional guidance for realtime OpenAI model behavior
• If the agent’s LLM speaks unexpected content, it’s often due to:
◦ The agent being asked to speak (agent identity) instead of receiving a user input.
◦ Race conditions where the model starts streaming before the intended initial input is processed.
• Ensuring the customer message originates from the participant side (frontend or simulated via text_received) avoids those problems because the agent receives explicit user input and will respond to it rather than produce its own unsolicited first utterance.
Quick checklist to implement
• Decide frontend vs. backend simulation.
• If frontend:
◦ Add a readiness signal (room connected / agent-ready event).
◦ Call localParticipant.sendText("Hello", { topic: 'lk.chat' }).
• If backend simulation:
◦ Add a short delay in on_enter.
◦ Call self.session.input.text_received(text="Hello", participant=self.session.room.local_participant).
Would you like a concrete frontend JS snippet for sending the text, or do you want me to help tune the delay/placement of text_received() in your current Python on_enter code? If you paste your current on_enter snippet, I’ll suggest the minimal change.
Sources: Text and transcriptions | LiveKit Documentation, with interactive elementstall-cricket-35295
04/03/2026, 5:37 AMawait self.session.generate_reply(user_input="Hello?")
will this work ?tall-airline-16756
04/03/2026, 5:37 AMawait self.session.generate_reply(user_input="Hello?") inside on_enter will not make the message originate from the customer. It tells the agent to generate a reply as if it had already received "Hello?", so the agent itself will speak/respond — not a customer participant.
Why:
• generate_reply(...) always produces an agent-originated response. Passing user_input only seeds the agent’s reply; it does not create a participant/chat event that looks like a customer message.
• That’s why you saw the agent “start speaking something else” when using generate_reply() — the agent is the active speaker and will generate content from its model.
What will work instead (pick one):
1) Frontend (recommended for production)
• Have the frontend participant send the actual user message after agent readiness:
◦ JS: localParticipant.sendText("Hello?", { topic: "lk.chat" })
• The agent will then receive that as a genuine participant message and reply naturally.
2) Backend simulation (for testing / automation)
• Simulate an incoming participant message after session init:
import asyncio
async def on_enter(self) -> None:
await asyncio.sleep(0.5) # ensure session is ready
self.session.input.text_received(
text="Hello?",
participant=self.session.room.local_participant
)
• This makes the agent handle "Hello?" as if a customer sent it.
If you absolutely must use generate_reply in `on_enter`:
• It will make the agent speak directly. To tightly control output, make instructions explicit (e.g., instructions="Reply exactly: Hello.") but this still originates from the agent, not the user.
Would you like:
• A short frontend snippet showing where to place sendText after agent readiness, or
• Help inserting text_received(...) into your current on_enter with the correct timing? Paste your on_enter if you want me to tweak it., with interactive elements