Claude Duet is an agent that messages you first. Watch the usage meter.

On October 21 Anthropic opened a research preview of Claude Duet, "a new app where Claude works as a proactive agent." The pitch is a reversal of how chat assistants usually work: instead of waiting for you to open a conversation, Duet comes to you with what it thinks needs your attention.

What it does. Each morning Duet sends a short brief on the most important items across your connected apps. During the day it checks those apps and messages you only when something needs you. You can also hand it tasks by text or voice in one ongoing thread, from scheduling meetings to building dashboards, forecasts, prototypes and small web apps. Anthropic says it runs on a virtual machine with its own browser, so your laptop or phone doesn't need to be on while it works. It is built around Claude Opus 5.5, and it carries over the memory, skills and connected apps from your Claude account, so there's little setup. Anthropic says it can use the more than 6,000 connectors and plugins in the Claude Marketplace, with examples like Gmail, Slack, QuickBooks, Stripe, Gusto, Docusign, HubSpot, Canva and Shopify.

The guardrails. Duet reads, drafts and prepares on its own, but before it sends a message, makes a payment, signs a document or deletes anything, Anthropic says it shows you exactly what it will do and waits for your approval. Some things are off-limits even with approval, such as trading securities or moving money between accounts. Anthropic says it never directly sees your passwords or sign-in tokens, and that a new classifier rejects requests to share the strictest tier of information, such as credit card numbers and government IDs. Purchases go through Link, Stripe's wallet, with a virtual card.

Who it's for. Anthropic says it built Duet "for professionals and small business owners with more on their plates than they can track." It's a waitlist preview for Claude Pro and Max subscribers in the US, as a standalone app on iOS and Android and on claude.ai. Team and Enterprise plans aren't included yet.

The honest caveat. Duet isn't free on top of your plan. During the preview it shares your plan's usage limits with the rest of Claude, its background checks count toward them, and big jobs like a financial model or a deck take more turns. Anthropic says Duet checks your accounts every few hours rather than constantly for exactly that reason, which also means it can miss something that arrives between checks. Anthropic also says it "might misread a thread or miscalibrate what's urgent," personal errands are weaker than work tasks, and you can't yet watch its browser.

MODEL has not tested Claude Duet hands-on; we're not on the waitlist yet. Everything above comes from Anthropic's announcement, product page and FAQ, read on October 21. This is not sponsored and has no affiliate links.