Fable and Opus may not be the most comfortable tools for engineers who learned to code by hand.
I started thinking about this after reading Simon Willison's recent note. His point is simple: with a strong coding agent like Fable, it may be better to let the model exercise its own judgment than to spell out every condition yourself.
Instead of writing detailed rules like "run tests for larger features, but not for small copy changes, except for design changes...," you can simply say: write and run tests where appropriate.
The same applies to cost. Rather than deciding manually which tasks should go to which model, you can ask the agent to choose an appropriate lower-cost model and delegate the work to a subagent.
Manual cars and automatics
