Simplifier

Simplifier

The middle mode between rehost and rearchitect: the system keeps its structure, loses its noise. Every pass is semantics-preserving — and proven so, not assumed: the characterization suite is the green bar every pass must hold. This skill owns the pass discipline; what to transform and what replaces a dependency comes from the composed stack ecosystem.

Preconditions

• The system runs on the target platform (1:1 lift completed).
• Characterization recordings exist and replay green. No green bar, no simplification — run /characterization-tests first.

Pass Loop

1. Pick one pass: a single transformation over a bounded scope, or a single dependency removal. Never batch.
2. Apply it.
3. Verify with the stack's own build/check loop, then replay the characterization suite.
4. Green → commit the pass. Diff → reconcile (an accepted behavior change is a human decision, per characterization-tests) or revert the pass entirely.
5. Log the pass in migration/SIMPLIFICATION.md — one line: date, pass, result.
6. Repeat until the catalog finds no high-impact transformation and the dependency list is settled.

Code Passes

The transformation catalog and its impact-to-risk ordering come from the composed stack ecosystem:

• Java — java-distiller: modern syntax, API upgrades, pattern adoption, dead-code removal.
• Web frontend — web-conventions + web-components: semantic HTML, modern CSS over framework classes, custom elements over framework widgets, standards-based routing and state.

Constraint on top, any stack: preserve the public surface and the structure — packages, components, routes stay where they are. Internals may simplify, dead code may go; moves, splits, and merges are carving, and carving is /bc-carver + /sbce territory.

Dependency Passes

One dependency per pass. The ladder shape is stack-neutral — platform first, then copied source, then keep with justification; the rungs are the stack's:

• Stop at the first rung that fits; keep only with a one-line justification in migration/SIMPLIFICATION.md under ## Kept Dependencies.
• Remove the dependency from the manifest in the same pass — replaced but still declared is an unfinished pass.

Rules

• The green bar is law: no pass survives a red replay unreconciled.
• Semantics shift in disguise — java.time timezone handling, stream ordering, third-party null handling; jQuery event semantics vs addEventListener, framework lifecycle vs custom-element callbacks, CSS cascade changes. That is why the bracket exists; trust the replay, not the reviewer's confidence.
• Stopping here is legitimate: a distilled, dependency-free system on a modern platform is a valid migration outcome.
• Continuing is better prepared: simplified code is cleaner input for /concept-extractor — half the naming noise the extractor fights is what these passes remove.