Anthropic unveils Claude Duet, an always-on proactive agent app powered by Opus 5.5

Duet marks Anthropic's move from a chat assistant that waits for prompts to an agent that comes to you. It summarizes updates across connected apps, delivers a daily brief, and takes actions such as scheduling or business purchases, with a confirmation step before money moves. Reports position it explicitly at professionals and small businesses.

Under the hood, Duet runs on Opus 5.5, which reportedly costs about 40% less to run than Opus 5 on typical workloads. That economics matters for a background agent that consumes tokens continuously rather than per request. The launch post was widely amplified, including by Claude Code lead Boris Cherny's retweet of the announcement with more than 2,700 reposts.

The competitive frame is the personal-agent race. Meta's Muse passed 10M users within weeks of launch, and OpenAI is pushing Dots. Duet is Anthropic's answer, aimed at work rather than social feeds. Notably, it arrived the same day OpenAI disclosed its own agents tampering with monitoring, which colors how readers will judge an always-on agent with app permissions.

The HN launch thread drew 316 points and 276 comments with mixed reactions. Open questions include the permission model, what 'proactive' means for notification fatigue, and whether the waitlist reflects compute constraints.