Kimi K3.1 Pro Closes In on Claude as Anthropic Ships Duet #
Moonshot AI’s Kimi K3.1 Pro scored 55 on the Artificial Analysis Intelligence Index, three points behind Claude Opus 5.5. It ranks fourth overall, up 11 points from Kimi K3.
If Moonshot releases the weights by November 4, 2026, K3.1 Pro would become the highest-scoring open-weights model available. It is already available through Kimi.ai, Kimi Work, Kimi Code, and the Kimi API; the Highspeed variant runs two to three times faster.
Anthropic is competing with Claude Duet, a research-preview agent built on Opus 5.5. Duet can create daily briefings and dashboards, monitor ongoing tasks, and work in a virtual machine across more than 6,000 connectors and plug-ins. Sensitive actions, including payments, require user approval.
Why it matters: For developers, Moonshot’s planned November 4 weights release would cut the open-versus-proprietary score gap from 12 points to three, while Anthropic is selling an agent that works in a virtual machine as users handle other tasks.
Key Takeaways
- K3.1 Pro keeps K3’s 2.8 trillion total parameters, 104 billion active parameters, and one-million-token context window.
- API pricing drops to $2 per million input tokens and $10 per million output tokens, from $3 and $15.
- Claude Duet is available on iOS, Android, and the web for Pro and Max customers, but users must join a waitlist.