Rain is a software and systems engineer at Oxide Computer Company who builds tools in Rust. They previously worked on Meta's Mononoke source-control system and write about software engineering at sunshowers.io.
Rain says Anthropic's Scion article understated the contribution of Meta's Mononoke design. Anthropic initially credited Sapling and Piper, then added specific Mononoke and Bonsai credit. The disagreement concerns attribution, rather than reuse itself.