replica

---
name: replica
description: Same-design migration — re-platform a site to AEM Edge Delivery (or any clean front end) keeping its current design near pixel-perfect. Recreates key pages (one archetype per page type) as clean re-authored HTML/CSS (never DOM copies), verifies each against the live site with a measured source-fidelity gate (structural + visual + stitched pixel diff per breakpoint), then hands off to migrate/deploy/rollout for site-wide delivery (subsumes prepare-migration's prep cascade — never chain the two). The only permitted design changes are entries in an explicit inconsistency register. Use when the user says "migrate this site keeping its current design", "same-design migration", "pixel-perfect replatform to AEM", or "keep the design, change the platform". NOT for redesigns — those are the stardust core pipeline (direct/prototype) or uplift.
license: Apache-2.0
compatibility: Requires Node 22+, Playwright with Chromium resolvable from the project, playwright-cli on PATH, and the impeccable skill (github.com/pbakaus/impeccable) installed alongside stardust.
---

# stardust:replica — same-design migration

Same pages, same content, same design — new platform. `replica` migrates a
site to AEM Edge Delivery (or just re-platforms its front end) keeping the
current design **near pixel-perfect**: the target spec IS the captured current
state, the only permitted deltas are the entries of an explicit
**inconsistency register**, and every archetype must pass a **measured
source-fidelity gate** against the live site before anything ships.

Two properties make this a different animal from the redesign pipeline:

1. **No creative decisions.** The direction step is mechanical promotion of
   the captured spec — the stardust `direct` skill is never invoked. Every judgment
   call in a replica run is a *measurement-policy* call, not a taste call.
2. **Recreation, not copying.** Archetypes are authored as clean semantic
   HTML/CSS from captured content + values lifted from the source site's own
   CSS — never DOM copies, never ported page-level stylesheets. Fidelity is
   proven by instruments, not asserted by construction.

Validated end-to-end (a typographic retail home page, 2026-07-03): 8.31% → 2.93% → **1.31%**
pixel diff in 3 measured iterations, height Δ 0, content-diff "findings:
none" (198/198 nodes). Every fix came off the instruments, never off
eyeballing.

## Inputs

- `<URL>` — required. The site to migrate.
- `--breakpoints <list>` — optional. Gate widths, default `1440,360`; each
  gets its own gate pass (mobile is not free — gate doc § Per-breakpoint).
- `--target-breakpoints <list>` — optional. Mobile-first `min-width` steps
  (e.g. `600,900,1200`) the delivered site switches layout at instead of the
  source's. Absent = source breakpoints kept, every target step below
  skipped. Persisted in `DESIGN.json` `extensions.breakpoints.target`.
- `--register <file>` — optional. User-supplied inconsistency items to seed
  the register (see Phase 2). Without it and without an audit, the register
  is empty — a pure replica.

## Setup

1. Run the master skill's setup (`../stardust/SKILL.md` § Setup): context
   loader, state read. **Flow guard.** If `state.json.flow` is
   `redesign`, refuse: print the never-mix line and the switch command
   (`$stardust replica --switch-flow`, which marks the redesign flow's
   prototyped and migrated pages stale — master skill § Two migration
   flows). If `flow` is absent, stamp `flow: "replica"`,
   `flowSource: "user-phrase"` (`../stardust/reference/state-machine.md`
   § Flow keys): invoking `replica` is the choice.
2. Verify Playwright is importable from the project root (extract needs it;
   so do the gate scripts).
3. Probe the gate's deps from the project root first —
   `node -e "import('pixelmatch').then(()=>process.exit(0))"` (and playwright,
   pngjs, cheerio) — and only on failure install them AS devDependencies,
   never `--no-save`: `npm i -D playwright pixelmatch pngjs cheerio
   --legacy-peer-deps` (a `--no-save` install is pruned by the next real
   `npm i` — recorded twice in one run, #125). A harness that already
   resolves them leaves the delivered code repo untouched; the
   devDependencies otherwise land in the repo the skills push. Run every
   probe from the project root: ESM resolves `playwright` from the script's
   own location.
4. Copy scripts into the project and run them from there, not from the
   plugin: this skill's whole `scripts/` dir to
   `stardust/scripts/replica/`, the master skill's `../stardust/scripts/`
   (ledger.mjs, state.mjs) to `stardust/scripts/stardust/`, the migrate
   skill's `../migrate/scripts/` (migrate.mjs) to `stardust/scripts/migrate/`,
   AND the whole
   `../diff/scripts/` dir to `stardust/scripts/diff/` (the diff scripts
   import diff-profiles.mjs, and ALL live-target hardening — including
   stitch-shot's — lives in its live-session.mjs; stitch-shot resolves it
   from `stardust/scripts/diff/` next to `stardust/scripts/replica/`, so
   keep the two dirs siblings). Never copy into the project-root
   `scripts/` — that is the EDS boilerplate's directory (master skill
   § Artifacts, the write boundary).

**Reading and inspection discipline — the context is the budget**
(`reference/reading-discipline.md`, read it once at Setup). Every byte a
step prints is re-read on every later model call (recorded: 750k characters
of tool output in one 77-minute session). The rules in one line each:
reference docs by section (`section.mjs <doc> --list`, then one heading, one
section per call); captured CSS through `css-rules.mjs`, capture JSON through
`json-query.mjs` (values that feed a command from `--tsv`/`--path`, never the
table), captured HTML through `html-slice.mjs`; instrument output through
`run-bg.mjs wait` and `log --grep`, never `cat`; live-vs-prototype boxes
through `measure.mjs`, never an authored probe; images one crop per fact,
never a stitched page or the live/build/diff triplet (the extract thumbnail,
`thumb.mjs`, is the one exception); script flags from
`../stardust/reference/scripts-index.md` first, then `--help`, never the
source. Write anything you will need again to a file under `stardust/` and
read it back by query.

## Procedure

Five phases. Phases 1 and 5 delegate to existing skills unchanged; phases
2–4 are owned by `replica`.

### Phase 1 — EXTRACT (delegate to `$stardust extract --prep --dynamics`)

Invoke `$stardust extract <URL> --prep`, unchanged. Prep mode is required —
replica consumes the full migration inventory, not the discovery cap:

- `stardust/current/pages/<slug>.json` — per-page structure + content
  (verbatim source of every string the prototypes will carry).
- `stardust/current/assets/screenshots/` — per-page captures (ground truth
  for recreation, alongside the gate's own stitched shots).
- `stardust/current/assets/` — fonts (network-intercepted woff2), logo, media.
- `stardust/current/PRODUCT.md`, `DESIGN.md`, `DESIGN.json` — the descriptive
  current state (Phase 2 promotes these verbatim).
- `state.json.pages[].type` — page types (each becomes one archetype).
- `DESIGN.json.extensions.modules[]` — module candidates (become blocks).

When extract's summary comes back, surface it with the flow line first —
"Flow: replica — the design is kept. Say `switch to redesign` now if it is
to change." — so the first thing the user sees in this flow is the choice
it rests on. `switch to redesign` runs `$stardust prepare-migration
--switch-flow`; the extract is reused, nothing else is.

**Bounded/single-page entry (one-page or pilot runs).** `--prep` is the
site-wide contract; it is NOT the only way in. When the ask is "replicate
just this page" — or the user wants to pilot one archetype before committing
to a full migration — invoke `$stardust extract <URL> --single --dynamics`
(or `--pages <slug,...> --dynamics` for a short list) instead. This is a first-class entry,
not an improvisation: the recreation phase needs, per page, the captured
page JSON (verbatim content), the per-page screenshot (ground truth), and
the captured fonts — all of which a bounded extract provides; the source-CSS
harvest and per-breakpoint computed styles come from Phase 3's CSS lifting
either way. What a bounded run skips is the prep-only inventory (page
typing, module detection), which is only needed when Phase 5 fans out to
siblings — a pilot that later grows to site scope re-runs Phase 1 with
`--prep`. **A bounded run also skips the descriptive synthesis**: crawl.mjs
alone writes `pages/<slug>.json`, screenshots, and `_crawl-log.json` — it
does NOT produce `current/PRODUCT.md` / `DESIGN.md` / `DESIGN.json`, so
Phase 2's verbatim promotion has nothing to promote. On this path Phase 2
takes the **bounded promotion branch** instead
(`reference/preserve-direction.md` § 1a): replica synthesizes a minimal
descriptive target spec from the captured page JSON + the Phase-3 CSS lift,
marked `provenance: bounded-single`.

Extract's failure modes apply as-is (bot-management headed fallback, consent
handling, no-synthesis rule). If extract had to fall back to headed Chrome,
expect the gate captures to need the same treatment.

### Phase 2 — PRESERVE DIRECTION (mechanical — never invoke the stardust `direct` skill)

Full contract: `reference/preserve-direction.md`. Summary:

1. **Promote** `stardust/current/PRODUCT.md`, `DESIGN.md`, `DESIGN.json`
   verbatim to the project root as the target spec. No divergence roll, no
   re-direction, no Mode A/B — the current state IS the target. **Bounded
   entry (`--single`/`--pages`): those files don't exist** — take the
   bounded promotion branch instead (`reference/preserve-direction.md`
   § 1a): synthesize a minimal descriptive spec from the captured page JSON
   + the Phase-3 CSS lift (palette, type ramp, container, buttons — exactly
   the values the lift produces anyway), provenance `bounded-single`. Never
   mix the branches: if `current/PRODUCT.md` exists, promotion is verbatim.
2. **Write `stardust/direction.md`** recording preserve mode: what was
   promoted, from where, provenance (verbatim `--prep` promotion vs
   `bounded-single` synthesis), and the register pointer. This is what
   tells downstream skills "the direction step happened".
3. **Build the inconsistency register** at
   `stardust/replica/inconsistency-register.md` — the ONLY permitted design
   deltas, the "almost" in almost-pixel-perfect. Sources: the stardust `audit` skill
   design findings (run audit only if the user wants improvement candidates)
   and/or user-supplied items (`--register`). Every entry needs captured
   evidence + the minimal change + a status. **Empty register = pure
   replica** — that is a valid and common outcome, not a failure.
4. **Target breakpoints (only with `--target-breakpoints`)**, before any
   CSS exists (`reference/preserve-direction.md` § 4): persist the list, map
   each source breakpoint to a step by intent in
   `stardust/replica/breakpoint-map.md`, seed the ONE register entry. Phase 3
   and C0 apply the map; they never decide it.

5. **Dynamic surface (migration gate — the stardust `dynamics` skill Phases 1–3).**
   Phase 1 must have run `extract --dynamics`. Run the detector on the
   archetypes, draft the triage (`--target-origin` when the EDS host is
   known), curate `stardust/dynamic-features.md` + `-plan.md`. Every row
   gets a disposition; the static recreation continues regardless. This is
   what surfaces modals, players, forms, search, tags and host-bound APIs
   that pixel gates certify as correct. Contract:
   `skills/dynamics/reference/triage.md`.

Anything not in the register is out of scope for change. When a recreation
choice would "improve" something not registered, it is a fidelity bug.

### Phase 3 — RECREATE (one archetype per page type)

Full method: `reference/recreation-procedure.md`. For each page type in the
inventory, author `stardust/prototypes/<slug>-proposed.html` (+ per-page CSS)
as **clean semantic HTML/CSS** from three sources, in this order:

(a) **Captured page JSON content — verbatim.** Headings, body, CTAs+hrefs,
    alt text, metadata from `current/pages/<slug>.json`. The migrate
    content-preservation rules (`../migrate/reference/content-preservation.md`)
    apply from the first line: no rewording, no fabrication.
(b) **Exact values lifted from the source site's own CSS.** Fetch the live
    stylesheets; lift the type ramp, button specs, section paddings, radii,
    shadows, hero heights. The container model is measured, not lifted —
    DESIGN.json `extensions.breakpoints` (extract's `cap-probe.mjs` run; a bounded
    entry runs `cap-probe.mjs <live-url> --write-design stardust/current/DESIGN.json` first).
    **Fidelity values come from the original site's CSS, not the eye** — this
    converts 3–4 guess-and-screenshot loops into one. Box-by-box comparison of
    the live page against the served prototype goes through the shipped
    `measure.mjs` (`node stardust/scripts/replica/measure.mjs <live-url>
    --against <prototype-url> --selectors "<css>,…"` — rect + computed values
    per selector per width, one delta line each), never through an authored
    probe.
(c) **The captured screenshot as ground truth** for everything CSS doesn't
    name (composition, image crops, paint effects).

**With a target set, every `@media` rule and JS width threshold
(`matchMedia`, `innerWidth`) is authored on the target steps from the first
line** per `breakpoint-map.md`, never fixed later (a retrofit costs a full
re-gate); `breakpoint-lint.mjs` exits 0 on a prototype before its gate.

**Every archetype gets its own standalone prototype — cumulative, never
skipped.** Never skip to direct platform authoring for a new archetype:
prototyped archetypes stayed the quality ceiling in the field (3.5%/5.6%)
while direct-authored pages plateaued at 8–16%. Each new prototype imports
the shared layers earlier ones already gated (shared canon CSS + a
per-archetype file) and iterates only on its NEW modules — full contract:
`reference/recreation-procedure.md` § Cumulative archetype prototypes.

**This is recreation, not redesign — do NOT delegate to impeccable craft.**
Impeccable's redesign gates (critique, anti-template, divergence) do not
apply; the source-fidelity gate (Phase 4) replaces them entirely. A
"tastefully improved" section is a failing section.

**Fonts:** use the same public source when available (extract's intercepted
woff2 for open/self-hostable faces). For licensed commercial kits: never
rehost on the new domain — pick a metric-matched substitute, keep the brand
family name first in the font stack so a licensed drop-in later wins, and
surface the substitution to the user. (Prior art: an earlier airport-site migration's improvement notes, §3.7.)

**CSS-portation is the per-section fallback only** — paint-level effects not
recoverable from computed styles, JS-hydrated commerce widgets, video or
animated heroes. Port the minimal source rules for that section, scoped;
never page-level. Criteria in `reference/recreation-procedure.md` § Fallback.

### Phase 4 — SOURCE-FIDELITY GATE (the heart — measured, per breakpoint)

Full contract: `reference/source-fidelity-gate.md`. Run per archetype, per
breakpoint (default 1440 AND 360), live URL as source vs served prototype:

```bash
PROTO="http://localhost:8791/<slug>-proposed.html"   # python3 -m http.server from the prototypes dir
# ONE server, ONE port — probe with curl first (gate doc § Per-breakpoint procedure): no answer →
# start yours; answers but not your file → foreign server, never kill it, take a per-project port
curl -sI localhost:8791/<slug>-proposed.html | head -1   # 200 = it serves YOUR dir: reuse it
LIVE="https://<site>/<path>"

# One command per round — gate.sh, through run-bg. The FIRST round of a breakpoint and the
# CONFIRMATION round after the last fix run `--full` (pixel probe — stitched captures, NEVER
# fullPage:true — plus content-diff, visual-diff and chrome-parity under deadlines, one verdict
# line each, reports in the gate dir); rounds in between are pixel rounds. Never hand-write a
# wrapper around the instruments (a recorded one lost the deadlines; a round took 15 minutes).
# content-diff inside --full compares --main AND the header/footer roots by default — no chrome flag.
node stardust/scripts/replica/run-bg.mjs start --name <slug>-1440-iter1 -- \
  stardust/scripts/replica/gate.sh <slug> "$LIVE" "$PROTO" 1440 iter1 --full --main "<content-root>"
node stardust/scripts/replica/run-bg.mjs start --name <slug>-360-iter1 -- \
  stardust/scripts/replica/gate.sh <slug> "$LIVE" "$PROTO" 360 iter1 --full --main "<content-root>"
node stardust/scripts/replica/run-bg.mjs wait      # verdict lines: pixel %, height delta, hot bands, structural 🔴, flags, chrome deltas

# Iteration inner loop (gate doc § Band breakdown): anchor probe + pixel round
G=stardust/replica/gates/<slug>-1440
node stardust/scripts/replica/anchor.mjs "$LIVE"  --width 1440 --cache $G/anchor-live.json   # live side: probed once, reused
node stardust/scripts/replica/anchor.mjs "$PROTO" --width 1440   # build-side runs are free
# Chrome: computed-style parity BEFORE any pixel round on header/footer/strips
node stardust/scripts/replica/chrome-parity.mjs "$LIVE" "$PROTO" --width 1440 --live-cache $G/chrome-live.json   # exit 0 = quiet, then crop-compare
# --headed anywhere in these instruments = the WINDOW-FREE real-Chrome stealth tier (live-session
# launchStealthHeaded, #125): it never opens a window; STARDUST_HEADED_WINDOW=1 is the only way to get one.
# gate.sh: live.png cached, every step under a deadline (exit 124 = re-run, not FAIL). Rounds run in
# the BACKGROUND: start every round at once (the slots pace the Chromiums — no `sleep N;` staggering),
# then `wait` prints verdict lines only; exit 75 = still going → `wait` again as your NEXT step, never
# in a shell loop, never after a `sleep` (gate doc § Iteration discipline). A propagation wait is a
# bounded inline poll (`curl -sf` ≤ 5 s apart, capped), never a fixed sleep.
node stardust/scripts/replica/run-bg.mjs start --name <slug>-1440-iter2 -- stardust/scripts/replica/gate.sh <slug> "$LIVE" "$PROTO" 1440 iter2
node stardust/scripts/replica/run-bg.mjs start --name <slug>-360-iter2  -- stardust/scripts/replica/gate.sh <slug> "$LIVE" "$PROTO" 360  iter2
node stardust/scripts/replica/run-bg.mjs wait      # returns within 100 s; full output: run-bg.mjs log <job> --grep <re>
# Content-cap row — once per archetype after the 1440 pass, at DESIGN.json's derived probeWidth (never a pinned 1920)
node stardust/scripts/replica/cap-probe.mjs "$LIVE" --against "$PROTO" --design DESIGN.json --slug <slug> --main "<content-root>"
```

`gate.sh --help` lists the flags and exit codes (124 = deadline, re-run, not
a verdict; 0 only when all four ran and passed).

**Pass bar (all four per breakpoint, plus the content-cap row):**
- content-diff: **0 structural 🔴** on the main root and the chrome roots — the default run covers both, each finding names its root (🟡/🟠 confirmed intended);
- visual-diff: flags none or justified;
- pixel diff: **≤ 10%** full-page, with no per-500px band left unexplained
  (the band breakdown is the navigation instrument — fix the first hot band,
  top-down; everything below it is offset-contaminated);
- height delta **|Δ| ≤ 8px** (pixel-compare's own warning bar);
- **content-cap row: `cap-probe.mjs … --against` prints `cap-probe: PASS`**
  (gate doc § Pass bar item 6 — every live cap held within ±20 px by kind,
  nothing capped only on the prototype; a ✗ names the sizing rule, no pixel iteration);
- **clip-probe: `Clipped: 0`** on the build side (a `--full` round runs it; cut or hidden
  text / controls fail the round like an over-threshold pixel diff — #125); a
  declared repeated-unit family (`stardust/replica/units.json`, gate doc item 7)
  within 4 px;
- and, outside the bar and outside the cap, the horizontal-overflow assert:
  `document.documentElement.scrollWidth` within 4 px of the viewport
  (integer rounding; `GATE_OVERFLOW_TOLERANCE`) at every breakpoint on the
  build side — gate.sh fails the round on more whatever the pixel number
  says; a `capture failed (exit 1)` round (after gate.sh's one
  retry) is re-queued, never counted.

**With a target set (#131):** gate widths add each target step; inside a
shifted band a pixel failure is **tier-shift** (logged against the register
entry, never iterated) or a **defect** (still fails) — gate doc § Target
breakpoints.

**Every prototype is a row (#125).** When the archetypes pass, one run per width
writes the prototype table — `node stardust/scripts/replica/gate-all.mjs --stage
prototype --proto-base "$PROTO_BASE" --width 1440` (then 360) through `run-bg.mjs`;
it reuses each archetype's cached `live.png`. `gate-evidence.mjs` reads it as the
source of record: a prototype without a row is ungated.

**Iteration discipline: hard cap 3 iterations per breakpoint.** Each
iteration's fixes come off the instruments, never off eyeballing. After 3,
log the residuals in the ledger and move on — a documented 2% residual beats
an undocumented fourth loop. **No single step waits longer than the context
cache lives:** long instruments go through `run-bg.mjs` (`start`, then `wait`
in ≤ 100-second slices), main agent and subagents alike — a long instrument
in the foreground, or two as parallel tool calls in one turn, is the same
blocked step (reference doc § Iteration discipline).

**Hardening (each is a recorded false-measurement trap — see the reference
doc for the full list):** real-Chrome UA **plus the standard request
headers** on every capture (built into the shared
`diff/scripts/live-session.mjs`); a challenge/blocked
interstitial **fails loud (exit 3)**, never measured — escalate with
`--headed`, and a site that still blocks needs crawl.mjs-class capture;
`domcontentloaded` on live targets, never `networkidle`;
symmetric `--main` scoping on both sides (`--main body` is never valid);
both overlay classes dismissed via `--dismiss` (consent AND timed marketing
modals); animations frozen for capture; the pointer parked after any
dismissal click; fixed/sticky chrome replicated fixed, with its
scroll-state morph, so seam repeats stay symmetric
(`reference/recreation-procedure.md` § Fixed and sticky chrome);
granularity-parity policy for JOIN/SPLIT false-reds (#87); capture-state
policy for CDN-403 images and hydration placeholders (replicate as captured
+ log). Two defect classes only the gate catches — DOM/style capture misses
them: rendered-face font forks on inner spans (width probe) and overlay
scrims invisible to computed styles (recover by per-row luminance fitting).

The live-target hardening ships as flags on the diff scripts (`--ua`,
`--wait-until`, `--dismiss`, `--headed`, `--locale`, visual-diff `--main`)
backed by `live-session.mjs` — copy the scripts and pass flags; a project
copy carrying hand-edits is a defect
(`reference/source-fidelity-gate.md` § Script adaptations).

**After the static gate passes, interaction parity is a REQUIRED gate
output per archetype — not a post-pass**
(`reference/recreation-procedure.md` § Interaction parity; optional, it was
skipped on 5 of 7 archetypes — all shipped static). Motion is OBSERVED,
never inferred from static classes or CSS: run
`stardust/scripts/replica/motion-observe.mjs` per archetype live URL →
`stardust/replica/motion/<slug>.json`, implement ONLY behaviors that
fired (dead classes = NOT implemented), then observe the served prototype
with the same `--click`/`--hover` pokes in the same order (→
`stardust/replica/motion/<slug>-build.json`) and compare the two files with
`stardust/scripts/replica/motion-compare.mjs` — one line per behavior
(parity / MISSING on build / EXTRA on build / timing delta / advisory) and a
summary line; it is a reporter, not a gate: a MISSING or EXTRA line is
confirmed on the class lines (the sampler misses class-toggled and
pseudo-element mechanics) and resolved in the prototype or recorded as dead.
Record
`motion: {observed, implemented, dead[]}` in `progress.json`, and re-run
pixel-compare — the number must return to the gated value.
Widgets are implemented, not justified away. Timer-driven media counts as
fired (`autoplay`/`loop` video, auto-advancing slides — the observe JSON's
`media` block): the capture freeze is logged as
`captureState[].restoreAtDelivery` and delivered, never shipped as the spec
("poster + paused" is not a deliverable). Fan-out briefs carry the
evidence rule + instrument invocation verbatim.

When all breakpoints pass, present the archetype + its gate metrics for
approval per the standard prototype approval flow (hands-off mode records
`approvedBy: "hands-off"` per `../stardust/reference/state-machine.md`).
Bookkeeping is one command each, never a hand-built JSON line or an inline
`node -e` edit of state.json: `node stardust/scripts/stardust/state.mjs advance <slug> --to
approved --by hands-off --prototype stardust/prototypes/<slug>-proposed.html`
and `node stardust/scripts/stardust/ledger.mjs replica source-fidelity-gate
end --detail "<per-breakpoint numbers>"`. Resuming a run starts with
`ledger.mjs tail` and `state.mjs summary --slugs`, not `cat`.
Every phase of this skill — extract and preserve-direction included — opens
with `node stardust/scripts/stardust/ledger.mjs replica <phase> start` as its
FIRST command, before any script of the phase runs (a recorded hands-off run
wrote a phase's `start` beside its `end` after 109 minutes of work and read
as idle to its supervisor; `ledger.mjs` refuses an `end` without an open
`start` under `--strict`), and closes with the `end` line plus a section in
`stardust/journal.md` headed `## <Phase name> — <what happened> (<date>)` —
the section is part of the phase `end`, and `ledger.mjs … end` warns when it
is missing (a recorded run's journal began at its second session; another's
had one section for the whole run).

### Phase 5 — HANDOFF (delegate — migrate → deploy → rollout, unchanged)

- **Read the contract card first: `reference/handoff-contract.md`** — the
  distilled migrate/deploy/rollout rules this phase needs, the exact rollout
  ledger phase strings (`A-inventory` … `I-dashboard`), one usage line per
  deploy and rollout script, and the bookkeeping commands. Never read the
  sibling SKILL.md files whole (one recorded session read 260k characters
  of them, then re-read the overflow, before its first Phase 5 output);
  fetch a cited section with `section.mjs` only when a step needs depth.
- **Pages beyond the archetypes** go through the stardust `migrate` skill at
  **sibling tier** (`../migrate/reference/fidelity-tiers.md`) — and only
  AFTER their archetype is live and gated at the published origin (contract
  § 3 row C, unit `C-archetype`; #126): structural clone as the encoder's
  input + content-fidelity + delivery-lint + media-reconcile; the sibling's
  only counting number is its gate row after PUT + preview (no local pixel
  bar). Siblings inherit the archetype's proven encoder — never re-author one. **Template constancy is measured, not
  assumed**: before cloning, run `stardust/scripts/replica/sibling-variance.mjs
  <archetype> <siblings…> --probe <block>=<sel> …` once per template and
  budget every delta as a block VARIANT class on the sibling's content (same
  file, § Sibling variance probe). Content-fidelity is
  **measured per page at import time** (same file, § Content-count
  acceptance) so importer bugs surface while cheap to fix.
- **Delivery** via the stardust `deploy` skill per page. Bias the decode tier toward
  **template-slotted** for fixed-composition sections (deploy #95): replica
  sections are fixed compositions matched to a live original.
  Repeat groups (cards, listings) stay reconstructive. **Blocks
  obey the Experience Workspace editability contract (deploy § 8, EW1–EW10:
  node-slotting, never value-slotting) and pass `block-roundtrip --ew`.**
- **Site-wide rollout** via the stardust `rollout` skill, unchanged — its block dedup
  is what implements "same blocks across the whole site".
- **Target breakpoints:** C0 authors the foundation and reused blocks on
  the target steps and wires `breakpoint-lint.mjs` into `npm run lint`
  (`reference/handoff-contract.md`), so every deploy and rollout lint pass
  enforces it.
- **C-deliver runs in units** (`reference/handoff-contract.md` § 3, row C +
  Fan-out discipline): C0 — ONE foundation subagent authors AND deploys the
  foundation; the main agent gates the shell on the published origin, then
  `foundation-freeze.mjs freeze` + commit; C-archetype — per template, the
  gated archetype is deployed and passes its full gate row on the preview URL
  (cap 3 fix rounds, then the re-prototype decision) BEFORE its siblings
  render; C1…Cn — one subagent per template
  cluster runs the whole chain, PUT → preview → published-origin gates
  included, with its own batch ledger (`deploy-batch.mjs --ledger …`,
  lock-safe) and reports one verdict line; the main agent only coordinates
  and records; C-final — `check`, the queued `foundation-requests.md` lines
  applied once, `C-deliver end`. Each unit is recorded in
  `stardust/rollout/progress.json` and committed — a safe resume point,
  never by itself a reason to end the session; no frozen file is edited
  mid-wave.
- **The final gate runs against the PUBLISHED origin — not the harness**
  (`reference/source-fidelity-gate.md` § The published-origin gate): deploy
  first (`PUT → preview`), then `gate.sh <slug> "$LIVE" "<preview-url>"
  <width> pub1 --full --marker "<brand or domain string>"` through
  `run-bg.mjs`, in the ordinary `gates/<slug>-<width>/` dir under the `pub<N>`
  label (a new dir would force a fresh live capture). Nothing pixel-shaped
  runs on the local harness — it feeds `qa-gate`/`block-roundtrip` only.
- **The delivery gate is the ALL-PAGES run, four criteria — not the pixel
  number alone** (`reference/source-fidelity-gate.md` § The all-pages
  published-origin gate, #125): `node stardust/scripts/replica/gate-all.mjs
  [--only <slug,…>] [--skip-existing] [--eds-host <host>]` through `run-bg.mjs`.
  DELIVERED = pixel % ≤ 10 AND |Δh| ≤ 5 % AND 0 clipped text / controls
  (`clip-probe`) AND 0 MISSING / HIDDEN links / headings (`content-presence`);
  a recorded page passed the pixel bar with all of its cards clipped. Evidence
  and sidecars: `stardust/replica/gates/all-<width>/`; with the Phase 4
  `prototypes-<width>/` table it is the pair `gate-evidence.mjs` reads (a page
  without a row is ungated). Each cluster subagent runs `--only` over its own
  pages inside the fan-out; C-final's roster run is the recorded unit
  `gate-all` (`--skip-existing`, captures reused) followed by
  `update-coverage.mjs --gate` (handoff contract § 3, row C).

**State:** replica writes its own state under `stardust/replica/` — the
inconsistency register, `progress.json` (per page type: archetype slug,
iterations used, per-breakpoint gate results, residuals, motion
inventory), `motion/<slug>.json`, and `gates/<slug>-<width>/` evidence.
The delivery gate (#125) adds `gates/all-<width>/` — one dir per deployed
page (`origin.png`, `eds.png`, `diff.png`, `pixel.json`, `content.json`,
`clip.json`, `units.json`), `summary.{json,md}`, `runs/` for `--only` runs and
the documented sidecars (`masks.json`, `overrides.json`, `clip-allow.json`,
`presence.json`, `units.json`).
Phase 5 adds three files under `stardust/rollout/`: `progress.json` (the
C-deliver unit ledger — status, gates and verdict per unit),
`foundation-freeze.json` (the sha256 manifest of the frozen foundation) and
`foundation-requests.md` (queued foundation change requests, applied once at
C-final). Pipeline status (extracted → prototyped →
approved → migrated) stays in the core `state.json` per the standard state
machine — replica never redefines it.

## What replica never does

- **No redesign.** No new palette, type, spacing, composition, motion. The
  target spec is the captured current state.
- **No content rewriting.** Captured strings are verbatim; placeholders and
  hydration states are replicated as captured, not "fixed".
- **No invented improvements.** A change without an inconsistency-register
  entry is a defect, however tasteful.
- **No DOM copying.** Never paste the live DOM or port page-level CSS as the
  prototype (that's the snowflake escape hatch, not this skill). Clean
  re-authoring is the point — byte-fidelity without re-implementation value
  defeats the migration.

## Outputs

```
stardust/
├── state.json                          ← core state machine (unchanged contract)
├── direction.md                        ← preserve-mode record (Phase 2)
├── current/                            ← from extract --prep
├── prototypes/<slug>-proposed.html     ← gated archetypes (one per page type)
├── replica/
│   ├── inconsistency-register.md       ← the ONLY permitted design deltas
│   ├── breakpoint-map.md               ← source → target breakpoint map (only with --target-breakpoints)
│   ├── progress.json                   ← per-page-type ledger: iterations, gate results, residuals, motion inventory
│   ├── motion/<slug>.json              ← motion-observe evidence
│   └── gates/<slug>-<width>/           ← live.png, proto.png, diff.png, probe outputs per iteration
├── migrated/                           ← from migrate (Phase 5)
└── rollout/                            ← from rollout (Phase 5); coverage/, plan.json … per its SKILL.md
    ├── progress.json                   ← C-deliver unit ledger: status, gates, verdict per unit
    ├── foundation-freeze.json          ← sha256 manifest of the frozen foundation (C0 → C-final)
    └── foundation-requests.md          ← queued foundation change requests, applied once at C-final

PRODUCT.md / DESIGN.md / DESIGN.json    ← promoted verbatim from current/ (Phase 2)
```

## References

- `reference/preserve-direction.md` — mechanical promotion contract +
  inconsistency-register entry schema.
- `reference/recreation-procedure.md` — CSS-lifting method (per gate
  breakpoint), fonts policy, scrim/luminance recovery, span-face forks,
  capture-state policy, wrap-junction margins, fixed/sticky chrome,
  granularity parity, role parity (mirror the live wrapping per string),
  interaction parity (motion observed, never inferred; Swiper-lock),
  CSS-portation fallback criteria.
- `reference/source-fidelity-gate.md` — full gate contract: commands,
  thresholds, per-breakpoint procedure, hardening rules, band-breakdown
  reading guide (+ the section-anchor inner loop), iteration discipline,
  the published-origin gate (EDS pipeline deltas), residual logging format.
- `../diff/SKILL.md` — the two probes replica reuses (`--profile generic`);
  reading content-diff output; the #87 JOIN/SPLIT limitation.
- `../extract/SKILL.md` § Prep mode — what Phase 1 provides.
- `reference/reading-discipline.md` — the reading and inspection rules in
  full: which helper reads what, the image rule, the evidence behind them.
- `reference/handoff-contract.md` — Phase 5 contract card: sibling-tier
  steps, deploy editability/decode/DA protocols, rollout phases A–I with
  their ledger phase strings, one usage line per deploy and rollout
  script, bookkeeping commands.
- `../stardust/scripts/ledger.mjs`, `../stardust/scripts/state.mjs` — the
  ledger and state writers (project copies under
  `stardust/scripts/stardust/`); `--help` on each.
- `../migrate/reference/fidelity-tiers.md` — archetype/sibling model Phase 5
  hands off to.
- `../deploy/SKILL.md` § decode tiers (#95) — template-slotted bias.
- `../stardust/reference/scripts-index.md` — every shipped script on one line
  (what it does, key flags); read it before any `--help`.

From adobe/skills at 940b879, shown as plain text under its license: Apache-2.0 (permissive). The license text is in plugins/stardust/skills/replica/SKILL.md.

• SKILL.md36 KB · 2a1097b3bbc2
• reference/
• handoff-contract.md61 KB · c6a6a20d579d
• preserve-direction.md11 KB · dc843c424295
• reading-discipline.md4.5 KB · 75b44ba7c379
• recreation-procedure.md43 KB · 17255e6e277c
• source-fidelity-gate.md58 KB · 63b01e81e089
• scripts/
• anchor.mjs11 KB · 9e49e06526a9
• breakpoint-lint.mjs13 KB · 6a518544994c
• cap-probe.mjs39 KB · c51808ef7a19
• chrome-parity.mjs19 KB · ec71485890be
• crop-compare.mjs7.7 KB · 80b65cb60e64
• css-rules.mjs9.6 KB · 908b90c93a00
• foundation-freeze.mjs11 KB · 939d2a711b69
• gate-all.mjs30 KB · 16b7d9894eb2
• gate-evidence.mjs42 KB · ca00cf7d26fa
• gate.sh23 KB · c90e17c3f3ad
• html-slice.mjs7.3 KB · b783ac54dbbf
• json-query.mjs13 KB · 4608419f41e6
• measure.mjs29 KB · 2ae5bd3b82f2
• motion-compare.mjs40 KB · 95e5a11c417b
• motion-observe.mjs22 KB · 525180f2f81b
• pixel-compare.mjs14 KB · 292194001866
• row-profile.mjs9.4 KB · db296b29c57e
• run-bg.mjs29 KB · 5770bb9ff9e5
• run-capped.mjs4.8 KB · f225916ab99c
• section.mjs7.2 KB · aa6ec82b14b6
• sibling-variance.mjs16 KB · ae7e6a77bf7b
• stitch-shot.mjs20 KB · 92cf9dfba5a8
• test/
• breakpoint-lint.test.mjs8.0 KB · f418845c5589
• cap-probe.test.mjs22 KB · f949c3a396e5
• foundation-freeze.test.mjs17 KB · 1d393ceeb372
• gate-all.test.mjs9.3 KB · 5c803d45c937
• gate-evidence.test.mjs50 KB · 51ff00d87c67
• gate.test.mjs24 KB · 6f3d0830a406
• inspect.test.mjs22 KB · 432004fd7902
• measure.test.mjs32 KB · 28ee991efe5a
• motion-compare.test.mjs27 KB · 74d9a545b9e7
• run-bg.test.mjs19 KB · 0aca0ac3f31f

38 files, 861 KB in total. Each file has a sha256 in the pin's manifest; the first 12 characters are shown.