Tip: one paragraph cuts Fable 5.1's unrequested fixes and surplus test files with no measured loss in task success

Anthropic·high signalXBlueskyLinkedInCopy link

The 'Keep changes and tests to what the task asks for' section reports that with an explicit leave-it-out instruction, unrequested additions and committed test code 'drop substantially with no measurable change in task success.' The block tells the model to report pre-existing bugs as follow-ups rather than fixing them, to implement the reading the wording most directly supports rather than building for both, and to commit tests only where the task asks or the repo already keeps them, sized like neighboring test files at roughly one focused test per stated behavior.