How Does Anthropic Launch a New Claude Model?

Katelyn Lesse says a Claude launch has become a machine, and the safety work is the complicated part. Outside that, the team makes the model, runs safety testing, and decides where the model needs to land.

They cut several versions and evaluate them, including on Anthropic's own work, which is how early mistakes show up before customers see a cut. When a set of variants feels solid, they cut a version for customers. Sometimes that goes through a first-party product such as Claude Code. Sometimes it goes to API customers in an early-access program, and those customers have to change their harness. The early group includes customers such as Cognition. The questions are plain: does it do well on your evals, do you like it, and what do you not like? Some of the feedback is a vibe, and some of it is the eval.

They launch when those pieces feel good together. The gap between a test cut and wider access stays short on purpose, so the customers in that program are the ones with robust evals who can come back with something the team can act on.