Subtract first

Subtraction is the question of what comes out, asked before anything goes in. Cleanup after a system has grown is a different act.

The smaller version is the default. The question precedes the addition. It does not wait for a review, and it does not run on a cadence.

Its subject is not code alone. Scope, features, and words are all subject to it.

The question fires at three moments. It fires before a standing requirement is optimized, before it is maintained, and before it is specified. It does not fire on every change.

The test for removal is the deterrent test. A requirement that has never fired is presumed removable. A usage count does not rebut that presumption. The one rebuttal is the answer to whether the thing the requirement guards against happens again once the requirement is gone. A requirement that has caught nothing and whose absence changes nothing is removable. A requirement that has caught nothing because its presence prevents the thing from occurring stays.

Removal of a standing requirement is advocated, never executed. The candidate is surfaced with its evidence, and the disposition belongs to a person.

Keeping a requirement because it exists, removing one without the deterrent test, and deleting a candidate rather than surfacing it are the three violations. The burden falls on keeping, and it is discharged by evidence.

The boundary sits at the moment of building. An explicit out-of-scope line records what was proposed by someone reasonable and taken out before the work began.

Inspection

How big are the instruction files you load at the start of every session, and when did we last take something out of one?

Held this, or broke it? Say which principle and what happened — tell me at /contact, subject Principles. What moves a band is somebody else's experience, and I'll publish what moved and who moved it.