AI agent designs a complete RISC-V CPU from a 219-word spec sheet in 12 hours (tomshardware.com)

From April 2026. It's not immediately obvious to me whether they did release the information promised, but it looks like somebody from Meta reproduced the effort using Claude Opus 4.6 and 4.7: https://github.com/tanfer-meta/vercore

It works be interesting to see how Opus 5.5 does with the same task.