Let visitors talk to your bot with voice calls

Add a call button to your web chat so visitors can talk to your bot out loud. The call uses the same bot they were typing to - same knowledge, same power-ups and the same conversation.

This page is about live voice calls. Typing by voice (the microphone button) and having answers read aloud are separate settings, Audio input and Audio output - see Voice input and read-aloud.

How a call works

• Visitors press the call button beside the message box and allow their microphone.
• The bot opens with a spoken version of your Welcome message.
• A voice agent handles speaking, listening and pacing. It asks your bot for answers and actions, and your bot uses its own instructions, knowledge and power-ups as usual. The voice agent can repeat an answer your bot has already given in the conversation without asking again.
• Text and voice share one conversation. A visitor can type a few messages, start a call and carry on where they left off. When the call ends, the transcript appears in the chat and they can keep typing.
• Callers can turn on live captions, download the transcript and mute their microphone.
• Each call has a time limit. Callers see a countdown in the last 30 seconds, the bot wraps up and offers to continue in text, and the call ends on time.

Turn on voice calls

1. Open your bot, select the Channels tab and click the settings (cog) icon on the Web card.
2. In the Voice calls section, turn on Enable voice calls. The toggle is only available when your team has voice minutes; the panel below it shows how many minutes are left and when the allowance resets.
3. Choose a Call voice and press play to hear a sample. Samples are prerecorded and use no call minutes.
4. Review the Voice instructions (see below).
5. Set Spoken language, Answer length, Maximum call duration (minutes) and, optionally, Monthly limit for this bot (minutes).
6. Click Update settings.

Voice settings

Voice instructions

Your bot's instructions are written for text, and often ask for bullet points, links or citations that make no sense spoken aloud. So the voice agent gets its own short instructions for how to speak, while your bot keeps following its original instructions for answers and actions.

• When you first turn on voice calls, Chat Thing drafts voice instructions from your bot's instructions.
• If you later change your bot's instructions, click Regenerate from system prompt to get a fresh draft. Saved voice instructions don't update on their own.
• Regenerating creates a draft. Click Update settings to save it.

Chat Thing also gives every call some fixed rules: the voice agent introduces itself as an AI assistant, asks your bot when it needs information or an action, and waits for confirmation before saying an action succeeded. Write your voice instructions to work with these rules.

Guided workflows

If your bot's instructions define a process - an intake interview, a product consultation, a step-by-step setup - your bot owns that process. Keep the full workflow, required questions, branching rules and completion conditions in the bot's instructions, and use voice instructions for spoken delivery plus a reminder to follow the bot's guidance. Copying every step into both creates two versions to maintain.

A reply such as "yes" or "dry" can move a process forward even though the caller hasn't asked a question, so the voice agent should check with the bot before choosing the first question and after answers that decide the next step. For a bot with a guided workflow, add something like this to its voice instructions:

When the caller wants to begin or resume the guided process, consult the bot before choosing the next workflow question. Ask one question at a time, following the bot's guidance. After each answer, consult the bot for the next step unless it has already explicitly supplied the applicable next step and no new decision, action or fresh check is needed. If the caller corrects an earlier answer, consult the bot to reconsider affected steps. Never invent, skip or reorder required steps, or announce completion before the bot confirms it.

When you review a generated draft, check it keeps the purpose of your process and the reminder to follow the bot's guidance. Add it yourself if it's missing.

Tips

• Describe the assistant's purpose and tone in a few clear sentences.
• Ask one question at a time and wait for the answer.
• When the caller corrects an earlier answer, check with the bot again so it can reconsider the affected steps, and keep answers that are still valid.
• Don't invent, skip or reorder required steps, or say the process is complete before the bot confirms it.

Minutes and limits

• Each call reserves up to its Maximum call duration when it starts, or less if your team's remaining minutes, this bot's monthly limit or the time left in the billing period is smaller. A call needs at least 30 seconds to start, ends when its reserved time runs out, and gives back what it didn't use.
• If there aren't enough minutes left to start a call, callers are told to continue in text. Text chat keeps working.
• Your bot's normal message token usage still applies when the voice agent asks it for answers.

Human handoff during a call

A person never joins the audio call. If someone on your team takes over the conversation during a call, the bot tells the caller a team member has taken over in the text chat, the call ends and the visitor carries on typing. The Talk to a human power-up works the same way: the bot explains that a person will follow up in text or by email.

Use a different voice on one website

If you embed the same bot on several sites, a developer can set a different call voice for one embed with the voiceName option. Everything else comes from the channel settings. See the JavaScript SDK.

Check it works

Test a complete call before relying on it: include a short answer, a correction and a final confirmation. If your bot runs a guided process, start it in text and continue by voice to check earlier answers carry over. A natural-sounding call can still miss a required step.

Troubleshooting

The Enable voice calls toggle is greyed out

Your team has no voice minutes available. The panel under the toggle explains why, for example that a voice add-on is needed or a renewal payment is pending. Team owners can manage the add-on from Billing.

Callers are told to continue in text

Your team's voice minutes have run out, or this bot has reached its Monthly limit for this bot (minutes). A limit of 0 pauses calls.

The bot sounds unlike your brand

Edit the Voice instructions, or improve your bot's instructions and click Regenerate from system prompt.