converse-sdk

The headless Python SDK for the Trelis Converse realtime voice API. Converse manages speech recognition, turn-taking, interruption handling, speech generation, reasoning and tool orchestration through a single API; this SDK connects telephony bridges, services, evaluations and custom devices to it.

uv add converse-sdk

The session-loop fragment below assumes your media layer supplies mic_frame and play_audio, and your application supplies run_tool:

import os

from converse_sdk import ConverseMode, ConverseSession, ToolDefinition

lookup_tool: ToolDefinition = {
    "name": "lookup_order",
    "description": "Look up an order by ID.",
    "parameters": {"type": "object", "properties": {"order_id": {"type": "string"}}},
    "read_only": True,
    "expected_duration": "instant",
    "status_label": "order lookup",
    "deferred": True,
    "deferred_timeout": 7200,
    "notify_on_complete": True,
}

session = await ConverseSession.connect(
    "wss://converse.trelis.com/ws",
    api_key=os.environ["CONVERSE_API_KEY"],
    mode=ConverseMode(
        instructions="Help callers with their orders.",
        greeting="Hello, how can I help?",
        tools=[lookup_tool],
    ),
)

async with session:
    await session.send_audio(mic_frame)  # PCM16 little-endian mono at 16 kHz
    await session.inject_context(
        "Claude Code finished. Tell the user briefly.", role="context", reply=True)

    async for event in session.events():
        if event.type == "audio":
            play_audio(event.audio)  # Float32 mono at 16 kHz
        elif event.type == "tool_call":
            result = await run_tool(event.data["name"], event.data["args"])
            await session.send_tool_result(
                event.data["id"], result, outcome="succeeded", verified=True)
        elif event.type == "tool_deferred_resume":
            resume_host_job(event.data["handle"])

deferred: True makes the tool a background job: the call can outlive the voice turn, the conversation carries on while the host works, and with notify_on_complete the agent speaks the result when it lands — even if the caller has moved on to another topic. For work that should release the voice turn immediately, call send_tool_deferred(id, handle, status_label=...) before continuing it in the background. The handle identifies that call, not your worker: mint a fresh one per call (e.g. f"job-{call_id}") and check the returned acknowledgement — re-using a live handle is rejected as handle_in_use, and a rejected defer leaves the call on the ordinary tool timeout, so it expires while you think it is backgrounded. Keep a handle-to-worker map if several calls should feed one long-running worker. For proactive host announcements, call await session.inject_context(text, role="context", reply=True, message_id="job-42"). It returns the broker's authoritative acknowledgement (accepted plus optional retryable/detail). For a typed user turn, the same message_id and input_source="text" appear on the final ASR event; spoken input uses input_source="voice". The role defaults to "context", reply defaults to False, and omitted message IDs are generated by the SDK. Text is limited to 1–2000 characters. An accepted message_id is an idempotency key for the logical session. After an acknowledgement loss, retry the identical payload and ID (including after resume) to replay delivery proof without injecting a duplicate turn. Reusing an accepted ID with different content is rejected; the broker retains up to 512 accepted receipts per logical session.

Save session.resume_token from the connected session; after a transport loss, pass it as resume_token=... to the replacement ConverseSession.connect(...) call so pending jobs are re-announced as tool_deferred_resume events within the broker's bounded resume window.

The SDK deliberately does not own capture, playback, pacing or echo cancellation. Live playback integrations must implement the playback contract.

See the complete Python reference and the Twilio bridge quickstart.

WebRTC transport (experimental)

Experimental: the API is stable, but this transport is newly shipped and still being hardened on real networks; ws remains the default and recommended fallback.

Pass transport="webrtc" to ConverseSession.connect(...) to carry the session over WebRTC (UDP) instead of the default WebSocket. Requires pip install "converse-sdk[webrtc]" (or uv add). ws remains the default; most headless callers are fine on it. See the Python guide's WebRTC section.

Licensed under the Apache License 2.0. This license applies to the SDK, not to the hosted Converse service, its models, or its server-side implementation. Runtime dependencies remain under their own licenses.