I accidentally used Fable to do a system upgrade and it was Fableous
A Flutter SDK upgrade I've done several times has a long manual tail that I've never been able to hand off. The tail includes deciding which golden-image failures are real and handling the checked-in images. It includes shuttling CI-generated Linux images back into the repo as new goldens. This time the agent did the whole workflow unprompted. It is the same repo, same skills , no new guidance . The only difference was that the session was left set to Fable from previous work instead of Opus or Sonnet. I upgraded a multi-platform Flutter library, all its tools and examples , to the latest Dart (3.13) , Flutter (3.47) , and mobile integration patterns using Claude Code . Using an LLM to do an upgrade in itself isn't that interesting. The interesting part is that I had switched to Fable, and Fable did way more with the same repo than I had seen in the past, with zero repo or skill changes. It felt like I handed off the work to someone. The work itself was routine: a multi...