Fable solved a long-standing bug in a Coleco Vision game that I have been working on with a small team of people. Fable did what both Claude 4.8 and ChatGPT/Codex could not do after many hours of attempts. Fable talked me through debugging the issues using an emulator. This is approx 10k lines of code in Z80 assembly. You can see the project here: https://github.com/plasticbugs/mrdoarcade

Our bugs have been squashed and now that Fable 5 has been recalled, Claude 4.8 is capable enough in Z80 assembly to help get the rest of the game across the finish line for a physical cartridge release. Claude 4.8 Z80 is iffy at best - scattershot approaches at hiding the bug symptoms. Fable 5's approach was to step back, analyze the issue, reproduce the issue with debugging in place and fix the root of the issue instead of a bunch of patchy fixes that hide the underlying bug.