Phone

A phone number from your Twilio account, answered by an agent you choose. The caller speaks; Twilio turns their words into text, the agent answers, and Twilio speaks the answer back. Every call is kept on the number with its transcript.

Phone numbers are under Channels › Phone.

What you need

• A Twilio account with a voice number in it. A number bought in Twilio appears in Synapse's list; buying one from Synapse isn't offered yet.
• A Twilio API key on that account, which you create in the steps below. Synapse never asks for your auth token.
• Self-hosted, a public https address Twilio can reach: the Webhook address on the Channels screen (messaging_webhook_base_url). A tunnel such as cloudflared works. Without it, a number can't be turned on.

Connecting a number

1. Open Channels › Phone and press Add a number.
2. Press Open API keys in Twilio's console, and create a key there. Pick the same kind in Synapse:
   • Restricted (recommended) can only do what calls need. Tick the permissions Synapse lists: reading and updating calls, and listing, reading and updating your active numbers. Add calls.recordings/create only if you will record calls, and recordings/read to play voicemail in a call's log.
   • Standard can do almost anything in your Twilio account. With it, Twilio also signs every request it sends to Synapse.
3. Paste the Account SID (it starts with AC), the API key SID (SK) and the API key secret, and press Check and continue. Synapse checks the key with Twilio straight away, stores it encrypted, and never shows the secret again.
4. Pick the Number. The list says where each one sends its calls now; connecting it sends them to your agent instead.
5. Choose the Agent that answers, and optionally a Name, What callers hear first and a number to Hand off to a person.
6. Press Connect number.

Synapse points the number at itself in Twilio. Turning the number off puts it back where it pointed before. If the key isn't allowed to change the number, the number's page shows Point this number by hand, with the address to paste into Twilio.

With a Restricted key, Twilio can't sign its requests, so the number's page says Calls are checked, not signed: each call is checked by the secret tokens in its address instead.

What a call sounds like

What callers hear first is said on every call before the agent speaks. Left empty, it is Hi, you're speaking with {agent}, an AI assistant for {org}. How can I help?, with the agent's and the workspace's names filled in for {agent} and {org}. Unless your own words end with a question, How can I help? is added, so callers know it's their turn. With recording on, This call may be recorded. is added.

While the agent looks something up, the caller hears a short phrase, once a turn, when a tool starts and the agent hasn't said anything yet; a second one if the tool is still running after 6 seconds. You set both on the number: While the agent looks something up and If the tool is still running after 6 seconds.

The caller can talk over the agent: it stops, and the conversation keeps only what the caller heard. After 8 seconds of silence the agent asks Are you still there?, twice, then says goodbye.

A call lasts at most Longest call, in minutes, 30 by default. A minute before the end, the agent is told to wrap up.

Language sets what the caller speaks and hears: pick the variant your callers use (English (India) hears an Indian accent better than English (United States)). Voice and Transcription choose the provider that speaks and the one that hears the caller; left alone, Twilio's defaults are used.

What the agent may do

Callers are always visitors: a phone number can be faked, so it never makes someone a member of your workspace. Under Who calls this number, tick what the agent may do for them, as for a chat widget. Nothing is ticked until you tick it.

The agent can also:

• Transfer the call to the Hand off to a person number, after its last words. If nobody answers, the caller can leave a voicemail. With no number set, transfers are off.
• End the call, after its last words.

A tool that needs approval asks someone in the workspace, and the caller is told someone will follow up. If someone approves while the caller is still on the line, the agent says the outcome on the call.

Every call is kept

The number's Recent calls list each call. Open one for its transcript and anything Waiting on you: an approval the call asked for, which an approver, builder or admin can answer.

Recording is off by default. Turned on, recordings stay in your Twilio account; Synapse keeps only the transcript, which it always keeps.

On SynapseOrch Cloud

The Phone screen and the calls work the same way. A call costs 4 credits for each started minute, charged once when it ends; the agent's turns inside it aren't charged again. Your plan sets how many calls run at once and the longest a call may last: see Settings → Plan.