Logic-Lens — Semantic Diff

When to Use

Use this skill when you need compare two code versions for semantic equivalence via semi-formal tracing of both versions side-by-side. Trigger when the user shares a refactor, rewrite, migration, or A/B implementation and wants to confirm behavior is unchanged — "did I break anything", "is this equivalent", "are...

Supporting prerequisites

Both tracked files are bundled, but the referenced sibling _shared/ library is not. Its L-codes, language rules and report template cannot be claimed as loaded here. Use the inline five-field finding structure and explicitly scoped traced scenarios unless a reviewed matching upstream installation supplies those shared files.

Setup

Use lazy loading per ../_shared/common.md §13:

1. Read ../_shared/common.md only for language, Iron Law, Verdict header, scope routing, Remedy discipline, config fields, and loading budget.
2. Read only the relevant step in logic-diff-guide.md as you reach it.
3. Load ../_shared/logic-risks.md, ../_shared/semiformal-guide.md, ../_shared/semiformal-checklist.md, and ../_shared/report-template.md on demand when the current step needs them.

Process