<!-- AUTO-GENERATED from detector-install-offer.md.tmpl — do not edit directly --> <!-- Regenerate: bun run gen:skill-docs --> <!-- Derived in part from nothing third-party: gstack's own consent flow for downloading impeccable's engine (Apache-2.0, see NOTICE.md). -->

Design detector: the one-time install offer

Read this only when the Setup probe printed DESIGN_DETECTOR_INSTALL_OFFER. It is the same question /design-review asks; whichever design skill runs first asks it, and the answer is remembered.

Install offer (one question, asked once). If the probe printed DESIGN_DETECTOR_INSTALL_OFFER: version=<v> platform=<p> bytes=<n> dest=<path>, the user has never answered this. Ask now, before any other step, in an interactive session only: with SESSION_KIND: spawned or a headless run, never install and never ask; continue as if the answer were "not now". In Conductor, render the brief as prose and STOP. Use this skill's AskUserQuestion format:

D<N> — Install impeccable's design detector engine?
Project/branch/task: <one line from the current work>
ELI10: impeccable is a separate Apache-2.0 tool (Paul Bakaus). Its engine is one <n>-byte program that checks pages and CSS for 61 mechanical design mistakes. gstack can download that one file (version <v>, from github.com/pbakaus/impeccable releases) into <dest>, check it against a checksum recorded in gstack, and log the download in ~/.gstack/security/egress.jsonl. No impeccable skill, no editor hook; the engine never touches the network when gstack runs it. Without it this skill works as it does today.
Stakes if we pick wrong: yes puts a third-party binary on this machine; no leaves machine-catchable design mistakes to judgment alone.
Recommendation: A because the download is pinned, logged, and reversible (delete <dest>).
Note: options differ in kind, not coverage — no completeness score.
Pros / cons:
A) Install the engine now (recommended)
  ✅ Every design review opens with 61 deterministic checks, tagged by rule id
  ✅ One checksum-verified file under your home directory, logged, removable with rm
  ❌ A third-party binary you did not build runs over your project files in scans
B) Not now
  ✅ Nothing changes on this machine; the question returns next time a design skill runs
  ❌ Design reviews keep relying on judgment alone for mistakes a machine can catch
C) Never ask again
  ✅ Design skills stay silent about impeccable (reversible: gstack-config set design_detector_install_prompted false)
  ❌ An engine you install later is still used, but gstack never reminds you
D) Turn the detector off
  ✅ No probe, scan, or handoff line in any design skill (gstack-config set design_detector off)
  ❌ An engine installed later is ignored until design_detector is back to auto
Net: a pinned, logged 16 MB download for machine-checked findings, versus every design check staying a judgment call.

On A, run the install and read its first line (IMPECCABLE_INSTALLED: <path> then the fresh probe lines, or IMPECCABLE_INSTALL_REFUSED: <reason>, after which this skill continues without scans):

bun --no-env-file --config=/dev/null run $HOME/.claude/skills/gstack/bin/gstack-design-detect.ts install --host claude

On B, continue without scans. On C, run ~/.claude/skills/gstack/bin/gstack-config set design_detector_install_prompted true. On D, run ~/.claude/skills/gstack/bin/gstack-config set design_detector off. Never pass --sha256 or --base yourself: they exist for maintainers and mirrors. If the user also wants the /impeccable skill and its hook, they run npx impeccable install themselves; gstack never does.