A Sunshowers post alleges that Anthropic’s Scion source-control system intentionally copied Mononoke, Meta’s source-control service, including Mononoke’s Bonsai changeset data model and related derived-data indexes. The author says private confirmation indicated personnel overlap between the teams and argues that Scion’s similarity could not have been accidental. The author also notes that “Scion” resembles “Bonsai” by reversing its syllables and removing the initial letter, while acknowledging that the name similarity could be coincidental. Mononoke’s Bonsai model uses a write-ahead-log-style Merkle DAG rather than the Git-like models the author describes as prevailing in source control. The author says Mononoke’s team designed and implemented the model in 2018 and spent roughly a decade productionizing and extending it, including work such as server-side rebases. The post says rebuilding an existing production system with an LLM in five months would still be notable, but less significant than independently designing and productionizing it. The author argues that copying technical ideas is acceptable when clearly attributed, but says crediting the broader Sapling ecosystem for “hard-won lessons” did not adequately identify Mononoke or Bonsai changesets. An update says Anthropic’s Nick G. responded on Hacker News and Anthropic added sufficient attribution to its blog post.