Today I tried Anthropic’s latest model, Fable, for the the first time. I asked it to run a full code review of the core Go code of rqlite.
Fable reject my first prompt as unsafe – review the rqlite code base for potential bugs – and Claude Code fell back to Opus 4.8.
I rewrote the prompt as:
You are in the code base of rqlite, the distributed database built on Raft and SQLite. I am the creator and maintainer of rqlite. We’re going to look methodically for potential improvements to the code base, package by package.
It then worked through the code as requested. It seems like looking for bugs is not acceptable, but looking for improvements is fine. While most of the issues Fable discovered were either unlikely to happen or were harmless, it did find one serious bug in the Change-Data-Capture system.
v10.2.7 is out now and comes mostly from working with Claude Fable.