Block says it uses Claude Fable to orchestrate thousands of code pull requests

Block's AI capabilities lead says the company uses Claude Fable to plan large code migrations and to direct smaller models, Opus and Sonnet, on individual tasks.

According to the account, Block routes work between frontier and smaller models based on the task. The report, published on Claude's blog, is first-party, so it reflects Block's own description rather than independent verification.

The lead also says that merges and production deployments remain behind human dual approval, meaning two people must sign off before code ships. The report does not provide measured results, such as error rates or time savings, for the orchestration approach.