Fable 5 Model Selection Checklist
A checklist for deciding when to choose the Fable 5 model, when to use a cheaper Claude model, and how to measure the result.
Model selection should be a repeatable decision. This checklist helps teams avoid using Fable 5 for everything or saving it only after a task has already failed.
Use Fable 5 when
The task spans many files, has ambiguous requirements, requires long reasoning, or would be expensive for a human to retry several times.
Use a cheaper model when
The task is short, deterministic, low risk, or mostly formatting. Premium reasoning is not needed for every operation.
Measure after the run
Track final result quality, test status, review effort, token cost, and whether the model needed repeated correction.
Bottom line
For Claude Fable 5, the right decision is practical: use it where stronger reasoning, longer context, and better coding judgment reduce total work. Measure the result against your own tasks before changing defaults.