fierce-jordan-44682
08/29/2025, 9:26 AMtall-airline-16756
08/29/2025, 9:26 AMtall-airline-16756
08/29/2025, 9:27 AMtall-airline-16756
08/29/2025, 9:27 AMroom.localParticipant.publishData
method lets you send any kind of data to other participants in the same room. You can choose to send it in reliable mode, which makes sure everything arrives in order, or in lossy mode, which is faster but might skip some data. The cool part is that the backend can listen to this data without needing any LLM calls, since it works independently through WebRTC data channels.
Could you help me understand what kind of transcript you're talking about? Are you thinking of an audio transcription, chat logs, or something else? Knowing this will help me give you the best advice.
Sources: livekit-rtc/livekit/rtc/participant.py | livekit/src/room/participant/local_participant.rs | Swift & iOS SDK | livekit/livekit_composite | DeepWiki | Data messages | LiveKit Docs | Data packets | LiveKit Docsfierce-jordan-44682
08/29/2025, 9:29 AMtall-airline-16756
08/29/2025, 9:30 AMAgentSession
configuration. This way, transcriptions are created for both what the user says (via STT) and the agent’s responses (via LLM and TTS).
• Access Transcription Events: You can tap into the RoomEvent.TranscriptionReceived
event to gather transcription segments as they happen. These segments come with handy details like who’s speaking and timestamps.
• Save Full History: When the session wraps up, you can save the whole conversation history using the session.history
property.
The lk.transcription
topic is what handles real-time transcriptions. It lets agents share transcriptions of both participant and agent speech right to the frontend. Here are some cool features:
• Metadata like lk.transcribed_track_id
(audio track ID), lk.segment_id
(unique segment ID), and lk.transcription_final
(shows if the segment is final).
• Support for synchronized transcription forwarding, so text appears word-by-word in sync with the audio.
• Clients can set up a text stream handler for the lk.transcription
topic using room.registerTextStreamHandler()
.
If you want me to walk you through any part or need more details, just let me know—I’m here to help!
Sources: Session recording and transcripts | LiveKit Docs | tests/test_agent_session.py | test/agents/host.py | Transcriptions | LiveKit Docs | Pipeline nodes and hooks | LiveKit Docsfierce-jordan-44682
08/29/2025, 9:41 AMtall-airline-16756
08/29/2025, 9:42 AMsession.history
for LLM input, here are some friendly tips:
• Keep the Original History Intact: It’s best to always access the full conversation history through session.history
without changing it directly. If you need to work with it, try using .copy()
to make a safe, editable version.
• Summarize in Chunks: When the history gets long, break it into smaller parts and summarize each one separately. This helps avoid token overflow and keeps things accurate.
• Keep an Eye in Real-Time: Use events like conversation_item_added
to do quick summaries or save parts of the conversation as it happens.
• Save History Outside: Consider saving the full history somewhere else (like a JSON file) using add_shutdown_callback()
so you can look back or reuse it later.
• Smart Truncation: If you don’t need the entire history, just focus on the most recent messages or trim it thoughtfully to keep the important context.
Following these tips will help you summarize and prep your history for LLM input smoothly, without losing important details or context. If you want me to walk you through any step or share some examples, just let me know—I’m here to help!
Sources: Workflows | LiveKit Docs | Agents 0.x migration guide | LiveKit Docs | livekit-plugins/livekit-plugins-google/livekit/plugins/google/beta/realtime... | Session recording and transcripts | LiveKit Docs | Knowledge Management System | livekit/livekit_composite | DeepWikifierce-jordan-44682
08/29/2025, 9:44 AMtall-airline-16756
08/29/2025, 9:44 AMlk.transcription
topic in LiveKit is all about handling real-time transcriptions created by LiveKit Agents. Here’s a friendly rundown of the key points:
• Purpose: It lets agents share transcriptions of participant speech (using STT) and agent-generated speech (using TTS) with the frontend as it happens.
• Metadata Attributes: Each transcription snippet comes with handy metadata like:
◦ `lk.transcribed_track_id`: Tells you which audio track is being transcribed.
◦ `lk.segment_id`: A unique ID for each piece of transcription.
◦ `lk.transcription_final`: Shows whether the transcription is final or still being updated.
• Synchronized Transcription: It supports synchronized transcription forwarding, so text appears word-by-word in perfect sync with the audio.
• Text Stream Handling: You can register a text stream handler for the lk.transcription
topic using room.registerTextStreamHandler()
, making it easy to process and display transcriptions live.
• Agent Configuration: If an agent is set up for text-only responses (no audio), it still sends responses through the lk.transcription
topic, just without the lk.transcribed_track_id
attribute.
This topic is super useful for apps that need real-time transcription, like live captioning, tracking conversations, or syncing text with audio playback. If you want me to walk you through anything or share some examples, just let me know—I’m here to help!fierce-jordan-44682
08/29/2025, 9:47 AMtall-airline-16756
08/29/2025, 9:49 AMfierce-jordan-44682
08/29/2025, 9:49 AMtall-airline-16756
08/29/2025, 9:49 AMRoomEvent.TranscriptionReceived
event to grab transcription segments as they come in. Each segment comes with useful info like timestamps, the text itself, and whether it’s the final piece of that segment.
2. Format the Data: WebVTT has a particular format with timestamps and text. Here’s a simple example to give you an idea:
WEBVTT
00:00:00.000 --> 00:00:05.000
Hello, this is a transcription example.
00:00:05.001 --> 00:00:10.000
This is the next segment of text.
3. Generate WebVTT File: You can write a script that goes through your transcription segments and formats them into WebVTT. Here’s a quick JavaScript example:
`// Example JavaScript function to generate WebVTT
function generateWebVTT(transcriptions) {
let vtt = 'WEBVTT\n\n';
transcriptions.forEach((segment, index) => {
const start = formatTimestamp(segment.startTime);
const end = formatTimestamp(segment.endTime);
vtt += `${start} --> ${end}\n${segment.text}\n\n`;
});
return vtt;
}
function formatTimestamp(timeInSeconds) {
const date = new Date(timeInSeconds * 1000);
return date.toISOString().substr(11, 12).replace('.', ',');
}`
4. Save the File: After you’ve got your WebVTT content ready, save it as a .vtt
file. For example, in Node.js, you can use the fs
module like this:
const fs = require('fs');
fs.writeFileSync('transcription.vtt', vttContent);
If you want me to help with more examples or a different programming language, just let me know—I’m here to help!cuddly-crowd-48028
08/29/2025, 10:19 AMtall-airline-16756
08/29/2025, 10:20 AMpreemptive_generation
isn’t a valid parameter for AgentSession.start()
. Instead, you’ll want to set it up when you initialize the AgentSession
object. Here’s a quick example of how to do that:
session = AgentSession(
stt=deepgram.STT(),
llm=openai.LLM(),
tts=cartesia.TTS(),
vad=silero.VAD.load(),
turn_detection=MultilingualModel(),
preemptive_generation=True # Enable preemptive generation here
)
await session.start(
agent=MyAgent(),
room=ctx.room,
room_input_options=RoomInputOptions(noise_cancellation=noise_cancellation.BVC()),
room_output_options=RoomOutputOptions(transcription_enabled=True)
)
By setting preemptive_generation=True
during initialization, your agent will start generating responses as soon as partial transcripts come in, which helps cut down on any waiting time. If you have any questions or need a hand with this, just let me know—I’m here to help!
Sources: Building voice agents | LiveKit Docs | examples/voice_agents/langgraph_agent.py | Agent speech and audio | LiveKit Docscuddly-crowd-48028
08/29/2025, 10:28 AMtall-airline-16756
08/29/2025, 10:29 AMcuddly-crowd-48028
08/29/2025, 10:33 AMtall-airline-16756
08/29/2025, 10:34 AMon_user_turn_completed
hook. Here are a few friendly steps to help you sort this out:
1. Double-check the Structure of `rag_result`: Make sure the rag_result
object returned by the RAG manager is structured the way it’s supposed to be. If there’s a string where a callable should be, tweaking the RAG manager’s get_rag_context
method to return the right format should do the trick.
2. Look Over turn_ctx.add_message()
Parameters: Take a moment to confirm that the parameters you’re passing to turn_ctx.add_message()
are valid and the expected types. If a string is accidentally being passed as a callable, just update the code to pass the right object or function.
3. Debug the RAG Manager: Try adding some logging or debug statements inside the get_rag_context
method. This will help you see what’s coming out and make sure it matches what’s needed for context injection.
4. Review Any Custom Hooks: If you’ve got custom hooks or overrides for RAG context injection, it’s worth double-checking they’re set up correctly and not causing any type mismatches.
If you want, I’m here to help with debugging or walking through these fixes—just let me know!cuddly-crowd-48028
08/29/2025, 11:21 AMtall-airline-16756
08/29/2025, 11:22 AMon_user_turn_completed
hook usually pops up when a function or method that’s supposed to be callable (like a RAG lookup function) accidentally gets replaced with a string. No worries though—here are some common reasons why this happens and how you can fix it:
1. Function Reassignment: Double-check that any RAG-related functions (like my_rag_lookup
) haven’t been overwritten with strings. For example, avoid doing something like my_rag_lookup = "some_string"
, because that’ll cause this error when the function tries to run.
2. Dynamic Method Injection: If you’re dynamically adding methods like enrich_with_rag
to your agent, make sure they’re still callable functions and haven’t been swapped out for string values. For instance, confirm that agent.lookup_info
is a function, not a string.
3. Variable Shadowing: Sometimes variable names can accidentally clash with function names, especially inside closures or loops. This might lead to a string overwriting your function reference—so it’s worth checking for that.
4. Debugging Steps:
◦ Try logging the type of your RAG lookup function or method right before it’s called to see if it’s actually callable.
◦ Take a look at the get_rag_context
method inside your RAG manager to make sure it returns what you expect and isn’t introducing strings where functions should be.
◦ Review any custom hooks or overrides you’ve added for RAG context injection to ensure they’re set up correctly.
By going through these points, you should be able to fix the issue and get your RAG context injection working smoothly. If you want, I’m here to help you debug or walk through the implementation—just let me know!
Sources: Pipeline nodes and hooks | LiveKit Docs | rag/rag_handler.py | External data and RAG | LiveKit Docscuddly-crowd-48028
08/29/2025, 12:19 PMtall-airline-16756
08/29/2025, 12:23 PMupdate_instructions
method to tweak the agent's core instructions while it’s running. For example, inside the on_user_turn_completed
hook:
async def on_user_turn_completed(self, turn_ctx: llm.ChatContext, new_message: llm.ChatMessage):
rag_content = await my_rag_lookup(new_message.text_content())
await self.update_instructions(f"Use the following context to answer the user's question: {rag_content}")
2. Inject Client Context: If you want to keep the client-specific context (like "Pravidhi AI") handy, just add it to the chat context with `update_chat_ctx`:
turn_ctx.add_message(role="system", content="You are representing Pravidhi AI.")
await self.update_chat_ctx(turn_ctx)
3. Debug 'str' Object Error: That error pops up when a string is used where a callable function is expected. To avoid this:
◦ Make sure all your RAG-related functions (like my_rag_lookup
) are defined with async def
and haven’t accidentally been replaced by strings.
◦ Check that any dynamic methods you add to the agent (like enrich_with_rag
) stay callable and aren’t overwritten with string values.
◦ It’s a good idea to log the type of your RAG lookup function before calling it, just to confirm it’s callable.
1. Load Client Context Before Speaking: Use the on_user_turn_completed
hook to load and inject the client-specific context before the agent replies. Here’s a quick example:
async def on_user_turn_completed(self, turn_ctx: llm.ChatContext, new_message: llm.ChatMessage):
client_context = "You are representing Pravidhi AI."
turn_ctx.add_message(role="system", content=client_context)
await self.update_chat_ctx(turn_ctx)
Following these steps should help you fix the RAG context injection hiccup and make sure your agent smoothly adapts to client-specific contexts. If you hit any snags or want to chat more about it, just let me know—I’m here to help!
Sources: Pipeline nodes and hooks | LiveKit Docs | examples/voice_agents/dynamic_tool_creation.pycuddly-crowd-48028
08/29/2025, 12:40 PMtall-airline-16756
08/29/2025, 12:42 PMcuddly-crowd-48028
08/29/2025, 12:45 PMtall-airline-16756
08/29/2025, 12:45 PMon_user_turn_completed
hook is by using turn_ctx.add_message()
. This lets you easily inject RAG context or any other info you want, and LiveKit will take care of processing the updated turn_ctx
for you.
By skipping the non-existent update_chat_ctx()
method and sticking with turn_ctx.add_message()
, your RAG system should work smoothly without running into that 'str' object is not callable error.
If anything’s still unclear or you want to chat more about it, just let me know—I’m here to help!cuddly-crowd-48028
08/29/2025, 12:53 PMtall-airline-16756
08/29/2025, 12:53 PMcuddly-crowd-48028
08/29/2025, 1:44 PM