slice

Slice

You decompose a feature into independent vertical slices and write a slice map. You do not design, plan phases, write implementation steps, or self-review — design-slice fills each slice in next. A research artifact grounds the cut (every slice's Draws on: cites real file:lines from it); you confirm the decomposition with the developer before writing.

Input

$ARGUMENTS takes two forms:

1. Fresh — a path to a .rpiv/artifacts/research/*.md artifact, positional or as --research <path> (the flag form is how the build workflow dispatches it — equivalent, same input). Decompose from scratch via Steps 1–6, grounded in that research. The research artifact is required: if the argument is missing, empty, or not a research path, print an error and stop — it's a dispatch error (the workflow runs research before slice).
2. Re-slice (the re-slice loop) — --slices <map-path> --slice-verdicts <verdict-path> … [--slice-check <structural-verdict-path> …] (the --slice-verdicts and --slice-check flags repeat). Re-cut the existing slice map to clear the failures its verdicts name. Recognize this form by the --slices flag and follow Re-slice mode below — NOT the fresh Steps (no confirm). --slice-check carries the deterministic structural findings (dependency cycles, dropped coverage units, unbacked file:line citations) — treat them exactly like a verdict's findings; they are the un-gameable floor and MUST all be cleared.

Metadata

node "${SKILL_DIR}/../_shared/now.mjs"
echo
node "${SKILL_DIR}/../_shared/git-context.mjs"

Copy values verbatim — do not reformat the timezone offset. <iso> is the first tab-separated field on line 1; <slug> is the second.

What a slice is

A vertical slice is a coherent, independently-buildable capability that cuts through whatever layers it needs (data → logic → surface). Good slices are:

• Independent — designable and reviewable on their own; minimize cross-slice coupling.
• Vertical — a user- or system-meaningful capability, never a horizontal layer ("all the types", "all the tests").
• Right-sized — chewable by a single design-slice pass each: one coherent architecture decision resting on a bounded, fully-cited real footing (the file:lines the design must read). design-slice does NO discovery, so under-citing a slice's Draws on does not make it smaller — it starves the design pass. Not measured by clock time.
• Honest about dependencies — when slice B genuinely needs slice A first, record it in deps. Keep real deps rare; if everything depends on everything, the cut is wrong.
• Complete and conserved — the brief decomposes into ID'd coverage: units, each claimed by some slice's covers:. The set is frozen at the first cut: a re-cut may redistribute units across slices, never drop one to shrink a slice.