guillotine

Guillotine

Remove weight the product does not use. Interior cleanup needs proof, not sentiment.

Contract

Inputs

• The subsystem or repository region to purge. Named explicitly or derived from the observed debt surface.
• The observable boundary: the commands, public routes, generated outputs, or user scenarios that must remain unchanged. Required; if no boundary can be named, the skill stops before editing.
• The repository-native gate command that defines "passes". Required, or discoverable in the repo.

Procedure

1. Name the subsystem and its observable boundary. List the commands, public routes, generated outputs, or user scenarios that must remain unchanged. Done when: the subsystem is named and every boundary element is listed, or the skill stops because no provable boundary exists.
2. Build a candidate ledger. For each code path, document, test, dependency, configuration entry, workflow, or generated file, record its claimed job, live callers or readers, source of truth, and evidence that it is dead, duplicate, superseded, or reproducible. Done when: every candidate has an entry with its job, live consumers, source of truth, and evidence category named.
3. Classify every candidate into one of five categories. Dead: no live caller, route, import, loader, build step, or documented consumer. Duplicate: another artifact owns the same fact or operation and all consumers can move to it. Superseded: the active path covers the required contract and no supported path selects the old one. Generated residue: the repository generator reproduces the required output and does not select this copy. Keep: evidence still names a live job, even when the artifact looks ugly. Done when: every candidate carries exactly one classification and the five categories are exhaustive with no candidate unclassified.
4. Prove the cut from both directions. Search from each candidate to its consumers, then from each required consumer back to its owner. Run a focused behavioral, mutation, build, or generation probe when static references cannot prove necessity. Done when: every candidate has a bidirectional proof: consumer-to-candidate search and candidate-to-consumer search both confirm the classification, or a probe was run that settled the ambiguous case.
5. Stop for approval if the proposed cut reaches an observable API, user command, stored data, history, remote state, untracked file, credential, or critical target. Show the exact consequence and a recoverable alternative. Interior VCS-tracked debt with a proven unchanged boundary does not need a second approval. Done when: every approval-gated target is identified with its consequence and alternative stated, or no target requires approval and the cut proceeds.
6. Cut one dependency-closed slice at a time. Move live consumers to the single surviving owner, then delete the obsolete implementation, tests that protect only obsolete behavior, dependency entries, configuration, workflow steps, and generated copies. Do not leave aliases, shims, dual paths, tombstones, or "deprecated" wrappers. Done when: the slice is cut with all consumers migrated to one owner and no alias, shim, dual path, tombstone, or deprecated wrapper left behind.
7. Regenerate every repository-owned surface affected by the cut. Reject a generator that recreates the removed residue; fix its source selection instead of deleting its output again. Done when: every affected generated surface is regenerated and the generator does not reproduce the removed artifact.
8. Exercise the observable boundary and run the repository-native gate. If behavior changes, restore the smallest failed slice from VCS, correct its ledger classification, and continue with the remaining proven cuts. Done when: every named boundary element passes and the repository gate exits green, or the failed slice is restored and reclassified.
9. Re-run route, import, registration, and source-of-truth searches. Done when: the old path is absent from every search and every required consumer resolves to one live owner.