How do Opus 5 and Fable 5 differ in calibrating thinking depth?

Both models use the effort parameter, alongside query complexity, to calibrate how much thinking actually happens on a given turn, and both share the same high default effort level.

The key structural difference is that Opus 5 allows thinking to be explicitly disabled, at effort high or below, while Fable 5 and Mythos 5 always run with adaptive thinking on and have no disabled mode at any effort level.

So for Fable 5, effort and query complexity are the only levers that shape how much thinking happens, since turning thinking off entirely simply isn't an available option the way it is, with restrictions, on Opus 5.

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