@juspay/neurolink/dist/voice/livekit/brain.js

The pipe layer of an AI nervous system: one interface connecting provider neurons to your application, across three inference types — generate, stream and decide. `decide` returns typed, calibrated judgements from a non-generative model (~400ms, ~$0.00002

/**
 * Transport-agnostic voice brain.
 *
 * Given a user transcript and a stable conversation id, it streams the
 * assistant's reply as text deltas by calling `neurolink.stream()`. NeuroLink
 * owns history (via the conversation id and its memory layer) and tools (the
 * tool-calling loop runs inside `stream()`); this module never touches a
 * transport. The LiveKit worker (or any other transport) consumes the text
 * deltas and converts them to audio.
 *
 * See docs/features/livekit-voice-agent.md.
 */
import { logger } from "../../utils/logger.js";
/**
 * Extract spoken text from a stream chunk without type assertions.
 *
 * `StreamResult.stream` yields a union: text chunks (`{ content: string }`),
 * a no-output sentinel, and audio/image events. Only text chunks carry a
 * string `content`; everything else yields `undefined` and is skipped.
 */
function extractTextDelta(chunk) {
    if (typeof chunk === "object" && chunk !== null && "content" in chunk) {
        const value = chunk.content;
        if (typeof value === "string" && value.length > 0) {
            return value;
        }
    }
    return undefined;
}
/**
 * Create a voice brain bound to a configured NeuroLink instance.
 *
 * The returned `streamReply` is an async generator of text deltas for a single
 * turn. Aborting `turn.signal` stops the in-flight LLM and tool calls and ends
 * the generator promptly (barge-in support).
 */
export function createVoiceBrain(config) {
    const { neurolink, provider, model, systemPrompt, temperature, maxTokens, userId, } = config;
    async function* streamReply(turn) {
        const { transcript, conversationId, signal, ephemeral } = turn;
        if (signal?.aborted) {
            return;
        }
        // No sessionId means no history read and no turn stored for this call.
        const context = ephemeral
            ? {}
            : { sessionId: conversationId, conversationId };
        const turnUserId = turn.userId ?? userId;
        if (!ephemeral && turnUserId !== undefined) {
            context.userId = turnUserId;
        }
        const result = await neurolink.stream({
            input: { text: transcript },
            provider,
            model,
            systemPrompt,
            temperature,
            maxTokens,
            context: { ...context, tags: ["voice"] },
            // Every turn through this brain is spoken; stored messages are marked so.
            modality: "voice",
            abortSignal: signal,
            disableTools: false,
        });
        for await (const chunk of result.stream) {
            if (signal?.aborted) {
                logger.debug("voice.brain.turnAborted", { reason: "signal-aborted" });
                return;
            }
            const delta = extractTextDelta(chunk);
            if (delta !== undefined) {
                yield delta;
            }
        }
    }
    return { streamReply };
}