Trace Gemini Live applications

Trace your Gemini Live voice agents, built with the Google Agent Development Kit (ADK), to LangSmith with the LangSmith ADK integration. For high-level conventions, see Voice tracing fundamentals.

The ADK Live integration requires langsmith[google-adk-live] (separate from the langsmith[google-adk] batch integration, so non-streaming ADK users do not take on its dependencies). It is in development, so its API may change. To trace ADK’s non-streaming paths (text agents, tools, multi-agent workflows), see Trace Google ADK applications.

Gemini Live is a speech-to-speech model that ADK streams to your app as run_live events. The integration captures each conversation as a single LangSmith trace, with a span for every meaningful event (transcripts, tool calls, turn boundaries, and interruptions). You register one plugin and do not create any spans yourself. The flood of audio chunks is played but not traced.

Runner.run_live is not covered by ADK’s standard OpenTelemetry instrumentation, so this plugin is what produces a trace for a Live voice conversation.

Install

pip install "langsmith[google-adk-live]" google-genai

uv add "langsmith[google-adk-live]" google-genai

Voice apps also need an audio library such as sounddevice for microphone and speaker I/O.

Set environment variables

.env

LANGSMITH_API_KEY=<your-langsmith-api-key>
LANGSMITH_TRACING=true
LANGSMITH_PROJECT=gemini-live-voice
GOOGLE_API_KEY=<your-google-api-key>

Set up tracing

Import LangSmithLivePlugin and register it on your Runner. It runs alongside your own run_live loop, so your loop keeps doing only audio playback and UI:

from google.adk.agents.run_config import RunConfig, StreamingMode
from google.adk.runners import Runner
from google.genai import types as genai_types
from langsmith.integrations.google_adk_live import LangSmithLivePlugin

plugin = LangSmithLivePlugin(project_name="gemini-live-voice")

runner = Runner(
    app_name="voice-app",
    agent=root_agent,
    session_service=session_service,
    plugins=[plugin],
)

run_config = RunConfig(
    response_modalities=["AUDIO"],
    streaming_mode=StreamingMode.BIDI,
    input_audio_transcription=genai_types.AudioTranscriptionConfig(),
    output_audio_transcription=genai_types.AudioTranscriptionConfig(),
)

async for event in runner.run_live(
    user_id=user_id,
    session_id=adk_session.id,
    live_request_queue=queue,
    run_config=run_config,
):
    ...  # play audio, handle barge-in, update the UI

By default the plugin generates a thread id per conversation; pass a thread_id_provider to supply your own.

Transcription is opt-in. Set both input_audio_transcription and output_audio_transcription on the RunConfig, or the trace has no transcripts.

Record the conversation audio

Feed the plugin your microphone and playback audio, and it attaches a single stereo recording (user left, agent right) to the trace:

plugin.record_user_audio(mic_chunk)      # user mic PCM16
plugin.record_agent_audio(played_chunk)  # agent PCM16 as played

Record the user’s microphone capture before resampling it for ADK, and tap the speaker for the agent’s audio, so the recording reflects what was actually heard. Feed both channels at the same sample rate (the plugin’s sample_rate, 24 kHz by default). For the underlying attachment API, see Upload files with traces.

Next steps

Voice fundamentals

Core conventions for tracing voice agents.

Upload files with traces

Attach the conversation audio recording to your trace.

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Tracing setup

Configuration & troubleshooting

Reference

Trace Gemini Live applications

Install

Set environment variables

Set up tracing

Record the conversation audio

Next steps

Voice fundamentals

Upload files with traces

​Install

​Set environment variables

​Set up tracing

​Record the conversation audio

​Next steps

Voice fundamentals

Upload files with traces

Install

Set environment variables

Set up tracing

Record the conversation audio

Next steps