More on Anthropic's Scion ripping off Mononoke
Points and comments are a snapshot, not live.
Anthropic's Scion VCS intentionally copied Mononoke's data model without proper attribution, says ex-Meta engineer.
The author, who led the Mononoke team at Meta, details how Scion's changesets, derived data indexes, and server-side API mirror Mononoke's Bonsai data model. The name "Scion" reverses "Bonsai" with a dropped B. Anonymous confirmation revealed intentional copying with overlapping personnel. The author distinguishes copying from attribution: crediting only "Sapling's hard-won lessons" is insufficient. Anthropic's narrative of an LLM building Scion in five months is misleading given a decade of prior work. The achievement remains impressive but should be positioned as derivative.
What commenters are saying
The thread's dominant sentiment is that proper attribution matters more than copying itself. An Anthropic employee (nickg) responds, claiming they credited Sapling per Meta's external naming, and adding a footnote to clarify. He emphasizes Scion was built incrementally, starting as a read-only service, and required novelties for Git migration. Some commenters defend copying as validation of good ideas, while others criticize Anthropic for overhyping an LLM's role. A long-serving ex-Meta source control member has no problem with the post, though notes the current team is not unanimous.