bit-voice

Natural Indian voices for any product or game. Two things you can do:

• Talk live, from a web page: with Aarav, Bitroot's AI sales rep, or with your own character (a game NPC, a product guide).
• Speak a line: text to speech in 25 voices, English and Hinglish plus 10 Indian languages.

Voices are Sarvam Bulbul v3, speech recognition is Sarvam Saaras (Hinglish code-mix), the brain is Claude Haiku 4.5 by default. The voice service runs in India (voice.bitroot.club), next to Sarvam, to keep replies fast.

How a live conversation works

MCP carries tool calls, not live audio. So a conversation takes two steps:

1. Your server (or agent) calls start_voice_session. It returns a ws_url that is valid for 10 minutes and works once.
2. A browser opens that URL with the client script. The person talks; the voice answers.

<script src="https://voice.bitroot.club/client.js"></script>
<button id="talk">Talk</button>
<script>
  document.getElementById("talk").onclick = async () => {
    const { ws_url } = await fetch("/my-server/voice-session", { method: "POST" }).then((r) => r.json());
    const call = await BitVoice.connect(ws_url, {
      onState: (s) => console.log(s),        // connecting | live | ended | error
      onSpeaking: (on) => npc.talking = on,  // animate the character's mouth
      onTranscript: (line) => {              // each line as it is spoken
        if (line.final) chat.add(line.role, line.text);
      },
    });
    // call.mute(true); call.setVolume(0.8); call.hangup();
  };
</script>

Live transcript

During the call, onTranscript receives every line as it is spoken:

{ role: "agent" | "user", text: "…", turn: 3, final: true, interrupted: false }

• turn is the line's position in the session transcript, so it matches get_voice_session exactly.
• final: false lines are an early preview of what the person is saying. The same turn comes again with final: true when they finish. Act only on final lines.
• interrupted: true on an agent line means the person talked over it. text is what was actually said before the stop.
• get_voice_session also shows the transcript growing while the session is live. duration_sec and cost_inr are filled in when it ends.

Needs client.js 1.1.0 or later (BitVoice.version).

Keep the froots token (or the voice API key) on your server. Only the ws_url goes to the browser: it is signed, single-use and short-lived. Call connect() from a click or key press, because browsers only allow the microphone after a user gesture.

Tools

start_voice_session

Param	For	Notes
persona	both	aarav or custom
lead_name	aarav	Required. Aarav greets them by first name
lead_email, lead_company, lead_message	aarav	Optional. With an email, Aarav can book a meeting on cal.com/bitroot
source	aarav	Where the person came from. The CRM shows api:froots:<source>
name, personality	custom	Required. Who the character is and how they talk
objective	custom	What the character wants from this conversation
context	custom	JSON facts the character knows right now (game state, the player's inventory)
first_speaker	custom	agent (default) or user, for NPCs that wait to be spoken to
opening_line	custom	First line when the agent speaks first
voice	custom	Default shubh. See list_voices
language	custom	Default en-IN, which covers English and Hinglish
model	custom	claude-haiku-4-5 (default, most natural), sarvam-105b-conversations (fastest, cheapest, mostly English), deepseek-v4.1-flash
pace	custom	0.7–1.5, default 1.05
ambience, ambience_volume	custom	none (default), office, room; volume 0–40 %
idle_timeout_sec	custom	After this much silence the voice nudges, then says goodbye. 0 turns it off. Default 15
goodbye_line	custom	Said when the voice ends the conversation
max_duration_sec	both	Hard limit, 30–1800, default 600
webhook_url	both	Gets a JSON POST with the transcript and cost when the session ends
metadata	both	Echoed back in every result, never shown to the model

Returns session_id, ws_url, connect_by and a ready embed snippet.

Aarav sessions always use Aarav's CRM settings (playbook, voice, background) and create a lead in the Bitroot CRM. Nobody is ever phoned from a web session.

get_voice_session

session_id → status (created, live, ended, expired), result.transcript (grows during a live session), result.duration_sec, result.cost_inr, your metadata. For Aarav it adds crm: outcome, summary, lead score, qualification and any booked meeting, about 30 seconds after the call ends.

speak

text (max 1,500 characters), voice, language, pace, sample_rate → a WAV clip as an inline audio block. Use it for lines your game or product already wrote.

list_voices

Voices, languages, models and background sounds.

Writing good characters

• Let your code decide, let the voice speak. Compute facts in your game ("can_afford": false, "quest_done": true) and pass them in context. The voice model is not reliable at arithmetic or rules.
• Keep personality to a few sentences: who they are, how they talk, one quirk. Put the goal in objective.
• Replies are capped at about 30 words, so the conversation feels like talk, not a lecture. Set voice_rules: false through the REST API if you need longer answers.

Costs and limits

	Cost
Live conversation, Claude	≈ ₹4–6 per minute
Live conversation, Sarvam model	≈ ₹2–3 per minute
speak	≈ ₹0.003 per character

At most 5 live sessions run at once across all products; beyond that ws_url connections get a "busy" error. Every session has a hard time limit.

REST API

The same features are available without MCP at https://voice.bitroot.club/v1 (POST /v1/sessions, GET /v1/sessions/{id}, POST /v1/speak, GET /v1/voices) with Authorization: Bearer <voice API key>. Interactive reference: voice.bitroot.club/v1/docs. Ask Bitroot for a key per product.