Claude Duet Phone Number: Give Duet Calls and SMS With AgentLine (2026)

Claude Duet reads your email, watches your calendar, and messages you before you ask. What it cannot do is make a phone call. Anthropic's announcement lists connectors, a browser, and payments, but no phone number, no calling, and no SMS. AgentLine fills that gap with a real US or Canada number for a hosted phone agent that Duet can set up through your Claude connectors, on plans from $20 a month; $3.00 a month per extra number plus $0.12 a minute beyond the plan.

The Short Answer

To give Claude Duet a phone number, add AgentLine to your Claude account as a custom connector with the URL https://api.agentline.cloud/mcp, then ask Duet to create a hosted phone agent and provision a US or Canada number once you approve. The hosted agent makes and answers real calls and sends and receives SMS. Duet reads the transcripts afterward and can put anything that needs a reply in your morning brief. Setup takes about ten minutes and needs no Twilio account or telecom setup. The full step-by-step guide lives at Claude Duet + AgentLine.

What Claude Duet Is

Claude Duet is Anthropic's proactive agent for professionals and small business owners. Anthropic launched it on October 21, 2026 as a research preview, by waitlist, for Claude Pro and Max subscribers in the US. It runs as its own app on iOS and Android and on claude.ai, separate from the main Claude app. Duet is included in Pro and Max and uses the same usage limits as the rest of Claude.

Duet runs on Claude Opus 5.5 inside its own virtual machine with a browser, so it keeps working when your laptop is closed. It checks your connected apps every few hours, sends a short morning brief, and messages you when something needs a decision. It carries over the connectors, memory, and skills from your Claude account. Before it sends a message, makes a payment, signs a document, or deletes anything, it shows you the action and waits for approval.

Why Duet Needs a Phone Number

Duet is built to notice what needs attention. Plenty of what it notices ends in a phone call:

• A client who emailed asking for a callback
• A supplier or landlord who only answers the phone
• An appointment that needs confirming the day before
• A missed call from a lead that should be returned while it is still warm
• A service that sends a verification code by SMS

Without a phone line, Duet can only flag these for you. With AgentLine, it can hand them to a hosted phone agent and report back with the transcript.

How Duet and AgentLine Split the Work

• Duet spots the task, drafts the phone agent's prompt, and calls AgentLine's tools through your Claude connector.
• AgentLine provides the number, carries the call, transcribes the caller, and speaks the replies.
• You approve the prompt, the number purchase, and who gets called.

Duet never handles audio. The hosted AgentLine agent runs the live conversation from the prompt you approved, and Duet reads the transcript once the call ends.

How to Set It Up

1. Create an AgentLine account at agentline.cloud yourself. Duet does not see passwords or logins, so this part is yours.
2. In Claude, add a custom connector with the URL https://api.agentline.cloud/mcp. Sign in to AgentLine and press Allow on the consent page.
3. Open Duet and ask it to set up a hosted phone agent, for example a receptionist that returns client calls, and approve the prompt.
4. Approve a US or Canada number (included in your plan; $3.00/month beyond it).
5. Call the number from your own phone, then ask Duet to summarize the transcript.

If the connector does not show up in Duet during the research preview, Duet can do the same setup in the AgentLine dashboard through its browser.

Here is a prompt you can paste into Duet to start:

Read https://agentline.cloud/skill.md. Using the AgentLine connector, tell me what is needed to set up a hosted AgentLine phone agent for my business. Check in with me before you buy a number or place a call.

What It Costs

• Phone number: US or Canada, included in plans from $20/month; $3.00/month each beyond the plan
• Calls: $0.12/minute, billed per second after a one-minute minimum; a 0-second call is free
• SMS: $0.02/message on the same number, sent or received
• Claude Duet: included in Claude Pro and Max, on your Claude usage limits

What to Know Before You Start

• The number reaches your hosted AgentLine phone agent, not your Duet thread. Duet's own alerts and messages are Anthropic features and separate from this number.
• Duet's background checks count toward your Claude usage limits, so a phone task that needs many follow-ups uses more of your plan.
• Live lookups during a call, such as checking your calendar mid-conversation, need a persistent webhook service that AgentLine can reach.
• The phone agent should say it is an AI assistant at the start of every call and give any required recording or transcription notice.
• This is an independent AgentLine guide, not an official Anthropic integration.

Templates That Fit Duet

Duet is aimed at professionals and small businesses, so the closest starting points are the business ones. The AI After-Hours Receptionist answers the line when you cannot. The AI Appointment Reminder Agent confirms tomorrow's bookings by phone. The AI Scheduling Agent books time around your rules. Ask Duet to apply any of them to your new AgentLine agent.

Bottom Line

Duet is built to notice what needs doing. AgentLine lets it do the parts that need a call or a text. Connect AgentLine to Claude, approve a number, and the callbacks Duet used to leave in your morning brief can get done. If you use another agent too, the same setup works for Claude Code, OpenAI Dots, Hark, and the rest of the runtime guides.