Clones gbrain at a pinned commit (v0.18.2) and registers it via
`bun link`. Before any clone:
D5 detect-first — probes ~/git/gbrain, ~/gbrain, and the install
target for a valid pre-existing clone (package.json with name
"gbrain" and bin.gbrain set). If one is found, `bun link` runs
there instead of cloning a second copy. Prevents the day-one
duplicate-install footgun on the skill author's own machine.
After install:
D19 PATH-shadow guard — reads the install-dir's package.json
version, compares to `gbrain --version` on PATH. On mismatch:
exits 3, prints every gbrain binary on PATH via `type -a`, and
gives a remediation menu. Setup skills refuse broken environments
instead of warning and continuing.
Prereq checks (bun, git, https://github.com reachability) fail fast
with install hints. --dry-run and --validate-only flags let the
skill probe the plan without touching state; tests use them to
cover D5 and D19 without exercising real bun link.
Pin is a load-bearing version: setup-gbrain v1 verified against
gbrain v0.18.2. Updating requires re-running Pre-Impl Gate 1 to
verify gbrain's CLI + config shapes haven't drifted.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Garry Tan