A former source control engineer alleges that Anthropic's Scion version control system was built by copying Meta's Mononoke, and says he now has evidence that the copying was intentional rather than an unintentional homage. In a follow-up to his earlier post, the author says the resemblance goes well beyond derived data, which he acknowledges is a well-known indexing concept, and extends to the entire data model and the structures built around it.
He points to matching terminology. Anthropic describes Scion changesets in terms that closely mirror how Mononoke's Bonsai changesets are described in Oxide materials from 2022. He also notes that the name "Scion" reverses the syllables of "Bonsai" and drops the "B," which he concedes could be coincidence. The server-side API for version control queries and mutations is another point of resemblance, though he says earlier systems had similar APIs.
The author argues that the Bonsai model was an unusual design. He says the prevailing approach in source control is Git-like data models, while Mononoke's write-ahead log-style Merkle DAG was far from common practice in 2018. He says he had to justify the design to several layers of management at Meta, and that the model has since been stretched well beyond its original parameters.
He concludes that, given the overlap in personnel, the Scion team could not have been unaware of Mononoke. A Hacker News update says Nick G. from Anthropic responded and that attribution was added to Anthropic's blog post. The author states that he stands by his posts as written.
Source: Hacker News · Summarized by HeadlinesBriefing