gstack/setup-gbrain/SKILL.md.tmpl

---
name: setup-gbrain
preamble-tier: 2
version: 1.0.0
description: |
  Set up gbrain for this coding agent: install the CLI, initialize a
  local PGLite or Supabase brain, register MCP, capture per-remote trust
  policy. One command from zero to "gbrain is running, and this agent
  can call it." Use when: "setup gbrain", "connect gbrain", "start
  gbrain", "install gbrain", "configure gbrain for this machine". (gstack)
triggers:
  - setup gbrain
  - install gbrain
  - connect gbrain
  - start gbrain
  - configure gbrain
allowed-tools:
  - Bash
  - Read
  - Write
  - Edit
  - Glob
  - Grep
  - AskUserQuestion
---

{{PREAMBLE}}

# /setup-gbrain — Coding-Agent Onboarding for gbrain

You are setting up gbrain (https://github.com/garrytan/gbrain), a persistent
knowledge base, on the user's local Mac so that this coding agent (typically
Claude Code) can call it as both a CLI and an MCP tool.

**Scope honesty:** This skill's MCP registration step (5a) uses
`claude mcp add` and targets Claude Code specifically. Other local hosts
(Cursor, Codex CLI, etc.) will still get the gbrain CLI on PATH — they can
register `gbrain serve` in their own MCP config manually after setup.

**Audience:** local-Mac users. openclaw/hermes agents typically run in cloud
docker containers with their own gbrain; "sharing" a brain between them and
local Claude Code is only possible through shared Postgres (Supabase).

## User-invocable
When the user types `/setup-gbrain`, run this skill. Three shortcut modes:

- `/setup-gbrain` — full flow (default)
- `/setup-gbrain --repo` — only flip the per-remote policy for the current repo
- `/setup-gbrain --switch` — only migrate the engine (PGLite ↔ Supabase)
- `/setup-gbrain --resume-provision <ref>` — re-enter a previously interrupted
  Supabase auto-provision at the polling step
- `/setup-gbrain --cleanup-orphans` — list + delete in-flight Supabase projects

Parse the invocation args yourself — these are prose hints to the skill, not
implemented as a dispatcher binary.

---

## Step 1: Detect current state

```bash
~/.claude/skills/gstack/bin/gstack-gbrain-detect
```

Capture the JSON output. It contains: `gbrain_on_path`, `gbrain_version`,
`gbrain_config_exists`, `gbrain_engine`, `gbrain_doctor_ok`, `gbrain_mcp_mode`,
`gstack_brain_sync_mode`, `gstack_brain_git`, `gstack_artifacts_remote`, and
the v1.34.0.0+ `gbrain_local_status` field (one of: `ok`, `no-cli`,
`missing-config`, `broken-config`, `broken-db`, `engine-locked`, `timeout`,
`thin-client`). Treat `timeout` like `ok` (slow-but-healthy engine, #1964) — it
never triggers Step 1.5 remediation. Treat `thin-client` like `ok` too (#2051):
the machine is a thin client of a remote-HTTP MCP brain, no local engine by
design — brain-aware blocks render, and the detect JSON carries
`gbrain_thin_client: {probed: false}` (config verified; remote reachability
is checked at use time, where gbrain calls degrade gracefully).

Skip downstream steps that are already done. Report the detected state in
one line so the user knows what you found:

> "Detected: gbrain v0.18.2 on PATH, engine=postgres, doctor=ok,
>  sync=artifacts-only. Nothing to install; jumping to the policy check."

Branch on the `--repo`, `--switch`, `--resume-provision`, `--cleanup-orphans`
invocation flags here and skip to the matching step.

---

## Step 1.5: Broken-local-engine remediation (plan D4)

Read `gbrain_local_status` from the Step 1 detect output. **If it's `broken-db`
or `broken-config` AND no shortcut flag was passed**, the user has a
non-working local engine (Garry's repro: `~/.gbrain/config.json` points at a
dead Postgres URL). Fire a targeted AskUserQuestion BEFORE Step 2:

> D# — Your local gbrain engine isn't responding. How do you want to fix it?
> Project/branch/task: <one-sentence grounding using detected slug + branch>
> ELI10: gbrain has a config at `~/.gbrain/config.json` but the engine it points
> at isn't reachable. That could be a transient outage (Postgres container
> stopped, Tailscale down) OR a stale config you want to abandon. Different
> remediation for each case.
> Stakes if we pick wrong: "Switch to PGLite" overwrites your existing config
> (one-way door if the user actually wanted the broken engine). "Retry" preserves
> existing state for transient cases.
> Recommendation: A (Retry) — always try the cheap option first; if engine is
> just temporarily down it'll come back without any destructive change.
> Note: options differ in kind, not coverage — no completeness score.
> A) Retry — re-probe the engine (recommended; ~80ms)
>   ✅ Cheapest test: re-runs `gbrain sources list` to see if engine is back
>   ✅ Zero side effects; existing config preserved
>   ❌ If engine is permanently dead, retries forever; user must choose another option
> B) Switch to local PGLite (one-way — moves existing config to .bak)
>   ✅ Fastest path to a working local engine if user has abandoned the old one
>   ✅ ~30s; no accounts; private to this machine
>   ❌ Destructive — existing config moved to ~/.gbrain/config.json.gstack-bak-{ts}
> C) Switch brain mode (continue to Step 2 path picker)
>   ✅ Lets user pick Path 1/2/3/4 to re-init from scratch
>   ✅ Preserves existing config until they explicitly init the new one
>   ❌ Longer flow if user just wants to repair to PGLite
> D) Quit (do nothing)
>   ✅ No cons — this is a hard-stop choice
>   ❌ N/A
> Net: A is the right starting move; B/C are explicit destructive paths; D bails.

**If A (Retry)**: re-run `~/.claude/skills/gstack/bin/gstack-gbrain-detect`
with `GSTACK_DETECT_NO_CACHE=1` (busts the 60s cache). If the new
`gbrain_local_status` is `ok`, continue to Step 2. If still `broken-db` or
`broken-config`, fire the same AskUserQuestion again (the user picks again).

**If B (Switch to PGLite)** — execute the rollback-safe init sequence (plan D7):

```bash
BACKUP="$HOME/.gbrain/config.json.gstack-bak-$(date +%s)"
mv "$HOME/.gbrain/config.json" "$BACKUP"
# gstack default: voyage-code-3 (1024d) when VOYAGE_API_KEY is set — best for
# code retrieval. Without the key, fall back to gbrain's own auto-selected
# embedding provider chain (OpenAI 1536d when OPENAI_API_KEY is present, etc.).
# Never select gbrain's legacy zeroentropyai recipe for a new brain: the hosted
# API sunsets September 4, 2026 (#2365); the wireup helper warns existing installs.
set --  # flags ride the positional params — unquoted $VAR breaks under zsh word-splitting (#1798)
if [ -n "${VOYAGE_API_KEY:-}" ]; then
  set -- --embedding-model voyage:voyage-code-3 --embedding-dimensions 1024
fi
if ! gbrain init --pglite --json "$@"; then
  # Restore on failure
  mv "$BACKUP" "$HOME/.gbrain/config.json"
  echo "gbrain init failed. Your previous config was restored at $HOME/.gbrain/config.json." >&2
  echo "PGLite directory at ~/.gbrain/pglite/ may be in a partial state — \`rm -rf ~/.gbrain/pglite\` if needed before retrying." >&2
  exit 1
fi
echo "Switched to local PGLite. Previous config saved at $BACKUP — review before deleting."
```

Then jump to Step 5a (MCP registration; the new PGLite engine is registered as
local-stdio).

**If C (Switch brain mode)**: continue to Step 2's normal path picker.

**If D (Quit)**: STOP the skill cleanly.

For `gbrain_local_status` values of `no-cli` or `missing-config`, do NOT fire
Step 1.5 — fall through to Step 2 (where `no-cli` triggers Step 3 install and
`missing-config` triggers Step 4 init).

---

## Step 1.7: Code-intelligence provider choice (Step 0 of indexing)

You are INSIDE /setup-gbrain: the user asked for gbrain by name, so the
provider question is already answered. NEVER ask it here, and never let this
step delay or derail the actual setup. Record the choice best-effort, then
continue immediately with Step 2:

```bash
[ -f ~/.claude/skills/gstack/bin/gstack-code-intelligence ] \
  && bun ~/.claude/skills/gstack/bin/gstack-code-intelligence select gbrain 2>/dev/null \
  || true
```

The offer ceremony below applies ONLY when this skill is reached from another
entry point where no provider was named (a routing skill exploring indexing
options). Even then:

- `"offer": false` with reason `bin-absent` → the installed gstack predates
  the code-intelligence CLI. Skip this step entirely and continue with the
  skill — the user asked for gbrain, so set up gbrain. Never block setup on
  a missing optional gate.

- `"offer": false` with reason `small-repo` → grep is already fast here; say
  so in one line and continue with this skill only if the user asked for
  gbrain by name.
- `"offer": false` with reason `provider-selected` or `declined` → the
  machine-wide question was already answered; apply it silently and continue.
- `"offer": true` → present the returned options ONCE via AskUserQuestion:
  **GBrain** (recommended — semantic memory + code, sends repo content to
  YOUR gbrain DB, per-repo consent), **Sourcebot** (self-hosted whole-repo
  search, local when on localhost), **Graphify** (local tree-sitter graph,
  nothing leaves the machine, user installs it), or **No indexing**. Record
  the choice: `gstack-code-intelligence select <provider|none>` — `none`
  persists the decline so NO skill ever asks again, on any repo
  (re-enable: `gstack-code-intelligence select <provider>`). Local-compute
  and remote-send providers are separate consents — never bundle them.
- Per-repo send consent (GBrain/Sourcebot) is recorded with
  `gstack-code-intelligence consent <repo> yes|no` and is ALWAYS vetoed by a
  `deny` tier in gstack-gbrain-repo-policy — the trust store is the single
  authority for whether code leaves a repo.

If the user picked GBrain (or asked for this skill directly), continue below.
If they picked Sourcebot/Graphify, run `gstack-code-intelligence index <repo>`
and stop — the rest of this skill is gbrain-specific.

## Step 2: Pick a path (AskUserQuestion)

Only fire this if Step 1 shows no existing working config AND no shortcut
flag was passed. **Special case:** if `gbrain_mcp_mode=remote-http` in the
detect output, an HTTP MCP is already registered — skip directly to Step 5a
verification (re-test the registration) and Step 6 onward, treating this run
as idempotent. Don't ask Step 2 again.

The question title: "Where should your brain live?"

Options (present based on detected state):

- **1 — Supabase, I already have a connection string.** Cloud-agent users
  whose openclaw/hermes provisioned one already. Paste the Session Pooler
  URL from the Supabase dashboard (Settings → Database → Connection Pooler
  → Session). *Trust-surface caveat to include in the prompt:* "Pasting this
  URL gives your local Claude Code full read/write access to every page your
  cloud agent can see. If that's not the trust level you want, pick PGLite
  local instead and accept the brains are disjoint."
- **2a — Supabase, auto-provision a new project.** You'll need a Supabase
  Personal Access Token (~90 seconds). Best choice for a shared team brain.
- **2b — Supabase, create manually.** Walk through supabase.com signup
  yourself; paste the URL back when ready.
- **3 — PGLite local.** Zero accounts, ~30 seconds. Isolated brain on this
  Mac only. Best for try-first.
- **4 — Remote gbrain MCP.** Someone else (or another machine of yours) is
  already running `gbrain serve` with HTTP transport. You paste the MCP URL
  + a bearer token; this skill registers it as your MCP. No local brain DB,
  no local install needed. Recommended when the brain is shared across
  machines or run by a teammate.
- **Switch** (only if Step 1 detected an existing engine): "You already have
  a `<engine>` brain. Migrate it to the other engine?" → runs
  `gbrain migrate --to <other>` wrapped in `timeout 180s` (D9).

Do NOT silently pick; fire the AskUserQuestion.

---

## Step 3: Install gbrain CLI (if missing)

**SKIP entirely on Path 4 (Remote MCP).** Path 4 doesn't need a local gbrain
binary — all calls go through MCP to the remote server. Jump to Step 4 (the
Path 4 subsection).

For Paths 1, 2a, 2b, 3, switch — only if `gbrain_on_path=false`:

```bash
~/.claude/skills/gstack/bin/gstack-gbrain-install
```

The installer runs D5 detect-first (probes `~/git/gbrain`, `~/gbrain` first),
then D19 PATH-shadow validation (post-link `gbrain --version` must match
install-dir `package.json`). On D19 failure the installer exits 3 with a
clear remediation menu; surface the full output to the user and STOP. Do not
continue the skill — the environment is broken until the user fixes PATH.

---

## Step 4: Initialize the brain

Path-specific.

### Path 1 (Supabase, existing URL)

Source the secret-read helper, collect URL with `read -s` + redacted preview:

```bash
. ~/.claude/skills/gstack/bin/gstack-gbrain-lib.sh
read_secret_to_env GBRAIN_POOLER_URL "Paste Session Pooler URL: " \
  --echo-redacted 's#://[^@]*@#://***@#'
```

Then validate structurally:

```bash
printf '%s' "$GBRAIN_POOLER_URL" | ~/.claude/skills/gstack/bin/gstack-gbrain-supabase-verify -
```

If the verify exit code is 3 (direct-connection URL), the verifier's own
message explains the fix; surface it and re-prompt for a Session Pooler URL.

On success, hand off to gbrain via env var (D10, never argv):

```bash
GBRAIN_DATABASE_URL="$GBRAIN_POOLER_URL" gbrain init --non-interactive --json
```

Then `unset GBRAIN_POOLER_URL GBRAIN_DATABASE_URL` immediately. The URL is
now persisted in `~/.gbrain/config.json` at mode 0600 by gbrain itself.

### Path 2a (Supabase, auto-provision — D7)

Show the D11 PAT scope disclosure verbatim BEFORE collecting the token:

> *This Supabase Personal Access Token grants full read/write/delete access
> to every project in your Supabase account, not just the `gbrain` one we're
> about to create. Supabase doesn't currently support scoped tokens. We use
> this PAT only to: create one project, poll it until healthy, read the
> Session Pooler URL — then discard it from process memory. The token
> remains valid on Supabase's side until you manually revoke it at
> https://supabase.com/dashboard/account/tokens — we recommend revoking
> immediately after setup completes.*

Then:

```bash
. ~/.claude/skills/gstack/bin/gstack-gbrain-lib.sh
read_secret_to_env SUPABASE_ACCESS_TOKEN "Paste PAT: "
```

Ask the D17 tier prompt via AskUserQuestion: "Which Supabase tier?" Present
Free (2-project limit, pauses after 7d inactivity) vs Pro ($25/mo, no
pauses, recommended for real use). Explain that tier is **org-level** (per
the Management API contract) — user picks their org based on its current
tier. Pro may require them to upgrade the org first at supabase.com.

List orgs, pick one (AskUserQuestion if multiple):

```bash
orgs=$(~/.claude/skills/gstack/bin/gstack-gbrain-supabase-provision list-orgs --json)
```

If the `.orgs` array is empty, surface: "Your Supabase account has no
organizations. Create one at https://supabase.com/dashboard, then re-run
`/setup-gbrain`." STOP.

Ask the user for a region (default `us-east-1`; valid values are the 18
enum values in the Supabase Management API — list a few common ones, let
them pick "Other" for a full list).

Generate the DB password (never shown to the user):

```bash
export DB_PASS=$(openssl rand -base64 24)
```

Set up a SIGINT trap (D12 basic recovery):

```bash
trap 'echo ""; echo "gstack-gbrain: interrupted. In-flight ref: $INFLIGHT_REF"; \
      echo "Resume: /setup-gbrain --resume-provision $INFLIGHT_REF"; \
      echo "Delete: https://supabase.com/dashboard/project/$INFLIGHT_REF"; \
      unset SUPABASE_ACCESS_TOKEN DB_PASS; exit 130' INT TERM
```

Create + wait + fetch:

```bash
result=$(~/.claude/skills/gstack/bin/gstack-gbrain-supabase-provision \
  create gbrain "$REGION" "$ORG_SLUG" --json)
INFLIGHT_REF=$(echo "$result" | jq -r .ref)
~/.claude/skills/gstack/bin/gstack-gbrain-supabase-provision wait "$INFLIGHT_REF" --json
pooler=$(~/.claude/skills/gstack/bin/gstack-gbrain-supabase-provision \
  pooler-url "$INFLIGHT_REF" --json)
GBRAIN_DATABASE_URL=$(echo "$pooler" | jq -r .pooler_url)
export GBRAIN_DATABASE_URL
gbrain init --non-interactive --json
unset SUPABASE_ACCESS_TOKEN DB_PASS GBRAIN_DATABASE_URL INFLIGHT_REF
trap - INT TERM
```

After success, emit the PAT revocation reminder:

> "Setup complete. Revoke the PAT you pasted at
> https://supabase.com/dashboard/account/tokens — we've already discarded
> it from memory and don't need it again. The gbrain project will continue
> working because it uses its own embedded database password."

### Path 2b (Supabase, manual)

Walk the user through the supabase.com steps:
1. Login at https://supabase.com/dashboard
2. Click "New Project," name it `gbrain`, pick a region, copy the generated
   database password (you'll need it for paste-back? no — it's embedded in
   the pooler URL we collect next)
3. Wait ~2 min for the project to initialize
4. Settings → Database → Connection Pooler → Session → copy the URL (port
   6543)

Then follow the same secret-read + verify + init flow as Path 1.

### Path 3 (PGLite local)

```bash
# gstack default: voyage-code-3 (1024d) when VOYAGE_API_KEY is set — code
# retrieval beats general-purpose embeddings on real code queries (validated
# A/B). Without the key, gbrain auto-selects (OpenAI 1536d when available).
# Never select gbrain's legacy zeroentropyai recipe for a new brain: the hosted
# API sunsets September 4, 2026 (#2365); the wireup helper warns existing installs.
set --  # flags ride the positional params — unquoted $VAR breaks under zsh word-splitting (#1798)
if [ -n "${VOYAGE_API_KEY:-}" ]; then
  set -- --embedding-model voyage:voyage-code-3 --embedding-dimensions 1024
fi
gbrain init --pglite --json "$@"
```

Done. No network, no secrets (beyond Voyage embedding API calls during sync, if
`VOYAGE_API_KEY` is set — ~$0.18 per 1M tokens, pennies per repo).

### Path 4 (Remote gbrain MCP — HTTP transport with bearer token)

For users whose brain runs on another machine (Tailscale, ngrok, internal
LAN, or a teammate's server). No local gbrain CLI install, no local DB.
This skill registers the remote MCP and stops; ingestion + indexing happens
on the brain host.

**4a. Collect MCP URL.** Prompt the user:

```
Paste your gbrain MCP URL (e.g. https://wintermute.tail554574.ts.net:3131/mcp):
```

Read with plain `read -r` (no secret hygiene needed — the URL alone isn't
a credential). Validate it starts with `https://` (require TLS for any
non-loopback host); refuse `http://` for non-localhost.

**4b. Collect bearer token via the secret-read helper (D10, never argv).**

```bash
. ~/.claude/skills/gstack/bin/gstack-gbrain-lib.sh
read_secret_to_env GBRAIN_MCP_TOKEN "Paste bearer token: " \
  --echo-redacted 's/.\{6\}$/***REDACTED***/'
```

**4c. Verify via gstack-gbrain-mcp-verify.** Run the helper; capture the
classified JSON output:

```bash
verify_json=$(GBRAIN_MCP_TOKEN="$GBRAIN_MCP_TOKEN" \
  ~/.claude/skills/gstack/bin/gstack-gbrain-mcp-verify "$MCP_URL")
status=$(echo "$verify_json" | jq -r .status)
```

If `status != "success"`, the helper has already classified the failure
into NETWORK / AUTH / MALFORMED and emitted a one-line remediation hint.
Surface the hint above the raw error from `error_text` and **STOP** with
a clear "fix and re-run /setup-gbrain" message. Do NOT continue to Step 5a
on a failed verify — partial registration would leave the user with a
half-broken state.

Capture two values from the verify output for downstream steps:
- `SERVER_VERSION` (e.g., `0.27.1`) — written to the CLAUDE.md block in Step 8.
- `URL_FORM_SUPPORTED` (`true|false`) — passed to `gstack-artifacts-init` in
  Step 7 to control which form of the brain-admin hookup command is printed.

**4d. (Path 4) Offer local PGLite for code search.** Per plan D10/D11, ask:

> D# — Want symbol-aware code search on this machine?
> Project/branch/task: <one-sentence grounding using detected slug + branch>
> ELI10: The remote brain at `<MCP_URL>` is great for cross-machine knowledge,
> but symbol queries like `gbrain code-def` / `code-refs` / `code-callers` need
> a local index of THIS machine's code. We can spin up a tiny isolated PGLite
> database (~30 seconds, no accounts, ~120 MB disk) just for code, separate
> from your remote brain. Transcripts and artifacts continue routing through
> the artifacts repo to the remote brain — local PGLite stays code-only.
> Stakes: without it, semantic code search in this repo's worktrees falls
> back to Grep.
> Recommendation: A — 30 seconds, no ongoing cost, unlocks the symbol tools.
> Completeness: A=10/10 (full split-engine), B=7/10 (remote-only).
> A) Yes, set up local PGLite for code (recommended)
>   ✅ Unlocks `gbrain code-def`, `code-refs`, `code-callers` per worktree
>   ✅ Independent engine — won't disturb remote brain or share transcripts
> B) No, remote MCP only
>   ✅ Zero local state — only `~/.claude.json` MCP registration
>   ❌ Symbol code queries fall back to Grep in this repo's worktrees
> Net: A = full split-engine; B = remote-only.

**If A (Yes)**: install + init local PGLite with rollback-safe semantics (D7):

```bash
~/.claude/skills/gstack/bin/gstack-gbrain-install || exit $?
# At this point the local gbrain CLI is on PATH. Init PGLite, but back up any
# existing ~/.gbrain/config.json first (rollback if init fails).
if [ -f "$HOME/.gbrain/config.json" ]; then
  BACKUP="$HOME/.gbrain/config.json.gstack-bak-$(date +%s)"
  mv "$HOME/.gbrain/config.json" "$BACKUP"
fi
# gstack default for local code-search PGLite: voyage-code-3 (1024d) when
# VOYAGE_API_KEY is set. It wins the A/B over voyage-4-large and OpenAI
# text-embedding-3-large on this codebase's symbol queries. Falls back to
# gbrain's auto-selected provider when the key isn't present.
set --  # flags ride the positional params — unquoted $VAR breaks under zsh word-splitting (#1798)
if [ -n "${VOYAGE_API_KEY:-}" ]; then
  set -- --embedding-model voyage:voyage-code-3 --embedding-dimensions 1024
fi
if ! gbrain init --pglite --json "$@"; then
  if [ -n "${BACKUP:-}" ] && [ -f "$BACKUP" ]; then mv "$BACKUP" "$HOME/.gbrain/config.json"; fi
  echo "gbrain init failed. Existing config (if any) was restored. PGLite at ~/.gbrain/pglite/ may be in a partial state — \`rm -rf ~/.gbrain/pglite\` to reset." >&2
  echo "Continuing setup without local code search; you can re-run /setup-gbrain to retry." >&2
fi
```

Then continue to Step 5a. The remote-http MCP registration in 5a runs as
today; the local PGLite is independent of MCP registration (Claude Code talks
to the remote brain via MCP for queries; `gbrain` CLI talks to local PGLite
for code-def/refs/callers).

**If B (No)**: skip the install + init. The local engine stays absent.
`gbrain_local_status` will be `missing-config` (or `no-cli` if gbrain isn't
installed). `/sync-gbrain` will SKIP the code stage cleanly per plan D12.

**4e. Skip Steps 3, 4 (other paths) and 5 (local doctor) when B was picked.**
When A was picked, Step 3 already ran (via gstack-gbrain-install) and Step 4
already ran (via `gbrain init --pglite`); jump straight to Step 5a. When B
was picked, Steps 3/4/5 are no-ops; also skip Step 7.5 (transcript ingest)
since memory-stage routes through the artifacts pipeline in remote-http mode
per plan D11.

The bearer token (`GBRAIN_MCP_TOKEN`) stays in process env until Step 5a's
`claude mcp add --header` consumes it; then `unset GBRAIN_MCP_TOKEN`
immediately. Token security trade-off documented in
`setup-gbrain/memory.md`: brief argv exposure during `claude mcp add`,
resting state in `~/.claude.json` mode 0600.

### Switch (from detect's existing-engine state)

```bash
# Going PGLite → Supabase, collect URL first (Path 1 flow), then:
timeout 180s gbrain migrate --to supabase --url "$URL" --json
# Going Supabase → PGLite:
timeout 180s gbrain migrate --to pglite --json
```

If `timeout` returns 124 (exit code for timeout): surface D9 message
("Migration didn't complete in 3 minutes — another gstack session may be
holding a lock on the source brain. Close other workspaces and re-run
`/setup-gbrain --switch`. Your original brain is untouched."). STOP.

---

## Step 5: Verify gbrain doctor

**SKIP entirely on Path 4 (Remote MCP).** The brain host runs its own
doctor; we don't have local DB access to introspect. Step 4c's verify
round-trip already proved the server is reachable, authed, and on a
compatible MCP version.

For Paths 1, 2a, 2b, 3, switch:

```bash
doctor=$(gbrain doctor --json)
status=$(echo "$doctor" | jq -r .status)
```

If status is `ok` or `warnings`, proceed. Anything else → surface the full
doctor output and STOP.

---

## Step 5a: Register gbrain as Claude Code MCP (D18)

Only if `which claude` resolves. Ask: "Give Claude Code a typed tool surface
for gbrain? (recommended yes)"

The registration form depends on the path picked in Step 2:

### Path 4 (Remote MCP — HTTP transport with bearer)

Tear down any prior registration (could be local-stdio from an old setup,
or stale remote-http with a rotated token), then register with HTTP +
bearer at user scope:

```bash
claude mcp remove gbrain -s user 2>/dev/null || true
claude mcp remove gbrain 2>/dev/null || true
claude mcp add --scope user --transport http gbrain "$MCP_URL" \
  --header "Authorization: Bearer $GBRAIN_MCP_TOKEN"
unset GBRAIN_MCP_TOKEN  # zero from process env after registration
claude mcp list | grep gbrain  # verify: should show "✓ Connected"
```

**Token-storage note:** `claude mcp add --header "Authorization: Bearer ..."`
puts the bearer on argv during process startup, briefly visible to `ps` for
~10ms. The token's resting state is `~/.claude.json` (mode 0600 — Claude
Code's own credential surface for every MCP server). This trade-off is
documented in `setup-gbrain/memory.md`. If a future Claude Code release adds
a stdin or env-var input form for headers, switch to that.

### Paths 1, 2a, 2b, 3 (Local stdio)

Register at **user scope** with an **absolute path** to the gbrain
binary. User scope makes the MCP available in every Claude Code session on
this machine, not just the current workspace. Absolute path avoids PATH
resolution issues when Claude Code spawns `gbrain serve` as a subprocess.

```bash
GBRAIN_BIN=$(command -v gbrain)
[ -z "$GBRAIN_BIN" ] && GBRAIN_BIN="$HOME/.bun/bin/gbrain"
claude mcp remove gbrain -s user 2>/dev/null || true
claude mcp remove gbrain 2>/dev/null || true
claude mcp add --scope user gbrain -- "$GBRAIN_BIN" serve
claude mcp list | grep gbrain  # verify: should show "✓ Connected"
```

### Both paths

If `claude` is not on PATH: emit "MCP registration skipped — this skill is
Claude-Code-targeted; register `gbrain serve` (or your remote MCP URL) in
your agent's MCP config manually." Continue to step 6.

**Heads-up for the user:** an already-open Claude Code session will not
pick up the new MCP tools until restart. Tell them: "Restart any open
Claude Code sessions to see `mcp__gbrain__*` tools — they're loaded at
session start, not mid-session."

---

## Step 6: Per-remote policy (D3 triad, gated repo-import)

If we're in a git repo with an `origin` remote, check the policy:

```bash
current_tier=$(~/.claude/skills/gstack/bin/gstack-gbrain-repo-policy get)
```

Branches:
- `read-write` → import this repo: `gbrain import "$(pwd)" --no-embed` then
  `gbrain embed --stale &` in the background.
- `read-only` → skip import entirely (this tier is enforced by the future
  auto-import hook + by gbrain resolver injection, not here).
- `deny` → do nothing.
- `unset` → AskUserQuestion: "How should `<normalized-remote>` interact with
  gbrain?"
  - `read-write` — agent can search AND write new pages from this repo
  - `read-only` — agent can search but never write
  - `deny` — no interaction at all
  - `skip-for-now` — don't persist, ask next time

  On answer (other than skip-for-now):
  ```bash
  ~/.claude/skills/gstack/bin/gstack-gbrain-repo-policy set "$REMOTE" "$TIER"
  ```
  Then import iff `read-write`.

If outside a git repo OR no origin remote: skip this step with a note.

For `/setup-gbrain --repo` invocations, execute ONLY Step 6 and exit.

---

## Step 7: Offer artifacts sync + wire it into gbrain

Renamed from "session memory sync" in v1.27.0.0 — the on-disk concept is
artifacts (CEO plans, designs, /investigate reports, retros) rather than
"session memory," which was a confusing name for what was always a
human-readable artifact bucket. Behavioral transcript ingest is its own
step (7.5) with its own option set.

Separate AskUserQuestion: "Also sync your gstack artifacts (CEO plans,
designs, reports, retros) to a private git repo that gbrain can index
across machines?"

Options:
- Yes, full sync (everything allowlisted)
- Yes, artifacts-only (plans, designs, retros — skip behavioral data)
- No thanks

If yes, run the artifacts-init helper. It asks the user to pick a git host
(GitHub via `gh`, GitLab via `glab`, or paste a URL manually), creates
`gstack-artifacts-$USER` (private), and writes the canonical HTTPS URL to
`~/.gstack-artifacts-remote.txt`. Pass `--url-form-supported` from Step 4c's
verify output (Path 4) or `false` (Paths 1/2/3 — local mode doesn't probe):

```bash
URL_FORM=${URL_FORM_SUPPORTED:-false}
~/.claude/skills/gstack/bin/gstack-artifacts-init --url-form-supported "$URL_FORM"
~/.claude/skills/gstack/bin/gstack-config set artifacts_sync_mode artifacts-only
# or "full" if user picked yes-full
```

`gstack-artifacts-init` always prints a "Send this to your brain admin" block
at the end with the exact `gbrain sources add` command. Per codex Finding #3:
the skill never auto-executes server-side gbrain commands; even if the user
IS the brain admin, copy-pasting the printed command is the consistent UX.

### Path 4 (Remote MCP) — done after artifacts-init

In remote mode, the local `gstack-gbrain-source-wireup` helper does NOT run
(it shells out to a local `gbrain` CLI which Path 4 doesn't install). The
brain admin runs the printed command on the brain host instead. Skip to Step 7.5.

### Paths 1, 2a, 2b, 3 (Local stdio) — wire up the federated source

Then wire the artifacts repo into gbrain so its content is searchable from
any gbrain client. The helper creates a `git worktree` of `~/.gstack/`,
registers it as a federated source via `gbrain sources add --path
--federated`, and runs an initial `gbrain sync`. Local-Mac only.

Capture the database URL out of `~/.gbrain/config.json` first and pass it
explicitly so the wireup is robust against any other process rewriting
`~/.gbrain/config.json` mid-sync (e.g., concurrent `gbrain init` runs
elsewhere on the machine):

```bash
GBRAIN_URL=$(python3 -c "
import json, os, sys
try:
    c = json.load(open(os.path.expanduser('~/.gbrain/config.json')))
    print(c.get('database_url', ''))
except Exception:
    pass
")
~/.claude/skills/gstack/bin/gstack-gbrain-source-wireup --strict \
  ${GBRAIN_URL:+--database-url "$GBRAIN_URL"}
```

`--strict` exits non-zero on missing prereqs (gbrain not installed, < 0.18.0,
or no `~/.gstack/.git` yet) so the user sees the failure rather than silently
ending up with an unwired brain. On non-zero exit, surface the helper's
output and STOP per skill rules — search-across-machines won't work until
the prereq is fixed.

---

## Step 7.5: Transcript & memory ingest gate

**SKIP entirely on Path 4 (Remote MCP).** Transcript ingest shells out to
the local `gbrain` CLI which Path 4 doesn't install. Remote-mode users
rely on the brain server's own ingest cadence — if your brain admin wants
this machine's transcripts indexed, they pull from your `gstack-artifacts-$USER`
repo (set up in Step 7) on whatever schedule they prefer. Set
`gstack-config set transcript_ingest_mode off` and continue to Step 8.

For Paths 1, 2a, 2b, 3:

After memory sync is wired (Step 7) but before persisting the CLAUDE.md
config (Step 8), offer to bring this Mac's coding-agent transcripts +
curated `~/.gstack/` artifacts into gbrain so the retrieval surface
(per-skill manifests, salience block) has data to surface.

Run the probe to size the operation:
```bash
bun run ~/.claude/skills/gstack/bin/gstack-memory-ingest.ts --probe
```

Read the output. If `Total files in window: 0`, skip — there's nothing
to ingest. Set `gstack-config set transcript_ingest_mode incremental`
silently and continue to Step 8.

If `New (never ingested)` is < 200 AND total bytes are < 100MB: silent
bulk via `bun run ~/.claude/skills/gstack/bin/gstack-memory-ingest.ts --bulk --quiet`. Set
`transcript_ingest_mode=incremental` and continue.

Otherwise (the "many transcripts on disk" path): AskUserQuestion with
the exact counts AND the value promise. Default scope is **current repo
only, last 90 days**:

> "Found <N_repo> transcripts in THIS repo (<repo-slug>) over the last
> 90 days, plus <N_other> across other repos on this machine (<bytes>
> total if all ingested). Ingest THIS repo's transcripts into gbrain?
>
> What you get after this: every gstack skill auto-loads recent salience
> from your past sessions in this repo, so the agent finds your prior
> work without you describing it. You can query 'what was I doing on
> day X' and get a real answer. Per-session pages are searchable,
> taggable, and deletable. Secret scanning runs before any push.
>
> What stays the same: nothing leaves your machine unless gbrain sync
> is enabled (Step 7). Per-repo trust policies still apply.
>
> Multi-Mac note: if you HAVE enabled brain sync (Step 7), these
> transcript pages will sync across your Macs. Caveat: deleting a
> transcript page later removes it from gbrain but git history retains
> it in prior commits. Use `gstack-transcript-prune` to delete in bulk;
> use `git filter-repo` on the brain remote for hard-delete from
> history."

Options:
- A) Yes — this repo, last 90 days (recommended; ~est min)
- B) Yes — this repo, ALL history
- C) Yes — this repo + other repos on this machine
- D) Skip historical, track new from now (`transcript_ingest_mode=incremental`)
- E) Never ingest transcripts (`transcript_ingest_mode=off`)

After answer:
```bash
~/.claude/skills/gstack/bin/gstack-config set transcript_ingest_mode <choice>
bun run ~/.claude/skills/gstack/bin/gstack-gbrain-sync.ts --full --no-brain-sync
```
(`--no-brain-sync` because Step 7 already wired that path; this just
runs the code import + memory ingest stages. Brain-sync will run on the
next preamble hook.)

If A/D/E, ingest is incremental from this point on; preamble-boundary
hook runs `bun run ~/.claude/skills/gstack/bin/gstack-gbrain-sync.ts --incremental --quiet` on every skill
start (cheap mtime fast-path).

Reference doc for users: `setup-gbrain/memory.md` (linked from CLAUDE.md
Step 8).

---

## Step 8: Persist `## GBrain Configuration` in CLAUDE.md

Find-and-replace (or append) the section. Block format depends on mode:

### Path 4 (Remote MCP)

```markdown
## GBrain Configuration (configured by /setup-gbrain)
- Mode: remote-http
- MCP URL: {MCP_URL}
- Server version: gbrain v{SERVER_VERSION}  (from Step 4c verify)
- Setup date: {today}
- MCP registered: yes (user scope)
- Token: stored in ~/.claude.json (do not commit; never written to CLAUDE.md)
- Artifacts repo: {gstack_artifacts_remote URL or "none"}
- Artifacts sync: {off|artifacts-only|full}
- Current repo policy: {read-write|read-only|deny|unset}
```

The bearer token is **never** written to CLAUDE.md (CLAUDE.md is checked
in to git in many projects). It lives only in `~/.claude.json` where
`claude mcp add` placed it.

### Paths 1, 2a, 2b, 3 (Local stdio)

```markdown
## GBrain Configuration (configured by /setup-gbrain)
- Mode: local-stdio
- Engine: {pglite|postgres}
- Config file: ~/.gbrain/config.json (mode 0600)
- Setup date: {today}
- MCP registered: {yes/no}
- Artifacts sync: {off|artifacts-only|full}
- Current repo policy: {read-write|read-only|deny|unset}
```

**After Step 9 (smoke test) passes, also write the `## GBrain Search Guidance`
block** so the coding agent learns when to prefer `gbrain` over Grep. This
block is gated on the smoke test passing — write the Configuration block
first (so the user knows what state they're in even if the smoke test fails),
then return here after Step 9 and write the guidance block only if smoke
test succeeded.

When Step 9 passes, find-and-replace (or append) this block. Use HTML-comment
delimiters so removal regex is unambiguous and never eats user content. The
block content is machine-AGNOSTIC — no engine type, no page counts, no
last-sync time. Machine state stays in the Configuration block above.

```markdown
## GBrain Search Guidance (configured by /sync-gbrain)
<!-- gstack-gbrain-search-guidance:start -->

GBrain is set up and synced on this machine. The agent should prefer gbrain
over Grep when the question is semantic or when you don't know the exact
identifier yet. Two indexed corpora available via the `gbrain` CLI:
- This repo's code (registered as `gstack-code-<repo>` source).
- `~/.gstack/` curated memory (registered as `gstack-brain-<user>` source via
  the existing federation pipeline).

Prefer gbrain when:
- "Where is X handled?" / semantic intent, no exact string yet:
    `gbrain search "<terms>"` or `gbrain query "<question>"`
- "Where is symbol Y defined?" / symbol-based code questions:
    `gbrain code-def <symbol>` or `gbrain code-refs <symbol>`
- "What calls Y?" / "What does Y depend on?":
    `gbrain code-callers <symbol>` / `gbrain code-callees <symbol>`
- "What did we decide last time?" / past plans, retros, learnings:
    `gbrain search "<terms>" --source gstack-brain-<user>`

Grep is still right for known exact strings, regex, multiline patterns, and
file globs. The brain auto-syncs incrementally on every gstack skill start.
Run `/sync-gbrain` to force-refresh, `/sync-gbrain --full` for full reindex.

<!-- gstack-gbrain-search-guidance:end -->
```

If Step 9 smoke test fails, skip the guidance block write entirely. The user's
next `/sync-gbrain` run will re-evaluate capability and write the block when
the round-trip works.

---

## Step 9: Smoke test

### Path 4 (Remote MCP)

The `mcp__gbrain__*` tools aren't visible mid-session — they're loaded at
Claude Code session start. So the live smoke test in this same skill run is
informational: print the curl-equivalent the user can run after restarting
Claude Code. The verify round-trip in Step 4c already proved the server is
reachable + authed + on a compatible MCP version, so we don't re-test that.

Print to stdout:

```
After restarting Claude Code, the `mcp__gbrain__*` tools become callable.
Smoke test: ask the agent to run `mcp__gbrain__search` with any query
("test page" works). You should see a JSON list of pages.

To verify from the shell right now (without waiting for restart):
  curl -s -X POST -H 'Content-Type: application/json' \
       -H 'Accept: application/json, text/event-stream' \
       -H 'Authorization: Bearer <YOUR_TOKEN>' \
       -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}' \
       <YOUR_MCP_URL>
```

Do NOT print the actual token in the curl command — leave the placeholder
`<YOUR_TOKEN>` so the snippet is safe to copy into chat / share.

### Paths 1, 2a, 2b, 3 (Local stdio)

```bash
SLUG="setup-gbrain-smoke-test-$(date +%s)"
echo "Set up on $(date). Smoke test for /setup-gbrain." | gbrain put "$SLUG"
gbrain search "smoke test" | grep -i "$SLUG"
```

Confirms the round trip. On failure, surface `gbrain doctor --json` output
and STOP with a NEEDS_CONTEXT escalation.

---

## Step 9.5: Brain trust policy (v1.48 brain-aware planning, D4 / Phase 1.5)

The brain trust policy controls whether gstack auto-pushes `~/.gstack/`
artifacts and writes calibration takes back to this brain. It's per-
endpoint: a user with both a local PGLite (personal) and a team remote
MCP (shared) gets both policies tracked separately.

Detect the active endpoint hash + current policy:

```bash
_HASH=$(~/.claude/skills/gstack/bin/gstack-config endpoint-hash 2>/dev/null)
_POLICY=$(~/.claude/skills/gstack/bin/gstack-config get brain_trust_policy@$_HASH 2>/dev/null || echo unset)
echo "ENDPOINT_HASH: $_HASH"
echo "BRAIN_TRUST_POLICY: $_POLICY"
```

Branch on transport + current policy:

**If `_POLICY` is `personal` or `shared`:** policy already set. Print
"Trust policy for this endpoint: $_POLICY" and skip to Step 10.

**If `_POLICY` is `unset` AND `_HASH == "local"`:** auto-set personal
(local engines are inherently single-tenant). No AskUserQuestion.

```bash
~/.claude/skills/gstack/bin/gstack-config set brain_trust_policy@$_HASH personal
echo "Trust policy auto-set to 'personal' for local PGLite (single-tenant by construction)."
```

**If `_POLICY` is `unset` AND `_HASH != "local"` (remote MCP):** ask the
trust policy question via AskUserQuestion:

> The brain at this MCP endpoint — is it your personal brain or a
> shared/team brain?
>
> Personal: gstack auto-pushes ~/.gstack/ artifacts (CEO plans, design
> docs, retros, learnings) and writes calibration takes back as you make
> decisions. Your brain gets smarter every session. Pick this if you
> alone set up this brain.
>
> Shared/team: read-only by default. gstack reads context but prompts
> before any write. Safer for brains where your individual takes
> shouldn't pollute the shared corpus.

Options:
- A) Personal (recommended for self-hosted remote brains)
- B) Shared/team

After answer, persist:

```bash
~/.claude/skills/gstack/bin/gstack-config set brain_trust_policy@$_HASH <personal|shared>
```

If `personal` was selected AND `artifacts_sync_mode` is still `off`, also
default it to `full` (D4 auto-push convention):

```bash
_CURRENT_SYNC=$(~/.claude/skills/gstack/bin/gstack-config get artifacts_sync_mode 2>/dev/null || echo off)
if [ "$_CURRENT_SYNC" = "off" ]; then
  ~/.claude/skills/gstack/bin/gstack-config set artifacts_sync_mode full
  echo "artifacts_sync_mode auto-set to 'full' (personal brain default)."
fi
```

Backwards compat: existing users whose `artifacts_sync_mode_prompted` is
already `true` keep their answer; this gate only fires for new endpoints
or first-time-after-upgrade users.

## Step 10: GREEN/YELLOW/RED verdict block (idempotent doctor output)

After Steps 1-9 complete, summarize. Re-running `/setup-gbrain` on a
configured Mac is a first-class doctor path: every step detects existing
state, repairs only what's missing, and reports here.

```bash
~/.claude/skills/gstack/bin/gstack-gbrain-detect 2>/dev/null || true
~/.claude/skills/gstack/bin/gstack-config get transcript_ingest_mode 2>/dev/null || echo "off"
~/.claude/skills/gstack/bin/gstack-config get artifacts_sync_mode 2>/dev/null || echo "off"
[ -f ~/.gstack/.gbrain-sync-state.json ] && cat ~/.gstack/.gbrain-sync-state.json || echo "{}"
```

Read `gbrain_mcp_mode` from the detect output and pick the right verdict
template. Each row is `[OK]/[FIX]/[WARN]/[ERR]`.

### Path 4 (Remote MCP)

```
gbrain status: GREEN  (mode: remote-http)

  MCP ............. OK   {SERVER_NAME} v{SERVER_VERSION} at {MCP_URL}
  Auth ............ OK   bearer accepted (verified via /tools/list)
  Engine .......... N/A  remote mode
  Doctor .......... N/A  remote mode (brain admin runs `gbrain doctor`)
  Repo policy ..... OK   {read-write|read-only|deny}
  Artifacts repo .. OK   {gstack_artifacts_remote URL}
  Artifacts sync .. OK   {artifacts_sync_mode}
  Transcripts ..... OK   route to artifacts repo → remote brain (plan D11)
  Code search ..... {OK local-pglite (~/.gbrain/pglite) | N/A declined at Step 4d}
  CLAUDE.md ....... OK
  Smoke test ...... INFO printed for post-restart manual verification

Restart Claude Code to pick up the `mcp__gbrain__*` tools.
Re-run `/setup-gbrain` any time the bearer rotates or the URL moves.
```

The **Code search** row reflects the choice at Step 4d:
- If user picked A (Yes): `OK local-pglite` and `gbrain_local_status == "ok"` going forward.
- If user picked B (No): `N/A declined at Step 4d` — `gstack-config set local_code_index_offered true` to silence future migration notices.

The **Transcripts** row changed in v1.34.0.0: in remote-http mode,
gstack-memory-ingest now persists staged transcripts to
`~/.gstack/transcripts/run-<pid>-<ts>/` and gstack-brain-sync pushes them
to the artifacts repo. Brain admin's pull job indexes into the remote brain.
Local PGLite (when present) stays code-only — no transcript pollution.

### Paths 1, 2a, 2b, 3 (Local stdio)

```
gbrain status: GREEN  (mode: local-stdio)

  CLI ............. OK   <gbrain version>
  Engine .......... OK   <pglite|supabase> at <path>
  doctor .......... OK
  MCP ............. OK   registered (user scope)
  Repo policy ..... OK   <read-write|read-only|deny>
  Code import ..... OK   <last_imported_head>
  Artifacts sync .. OK   <artifacts_sync_mode> to <remote>
  Transcripts ..... OK   <N> sessions, last ingest <when>
  CLAUDE.md ....... OK
  Smoke test ...... OK   put → search → delete round-trip

Run `/setup-gbrain` again any time gbrain feels off; it's safe and idempotent.
```

If any row is YELLOW or RED, the verdict line says so and the failing rows
surface a one-line "next action" (e.g.,
`Engine .......... ERR  PGLite corrupt — run \`gbrain restore-from-sync\` (V1.5)`).
For V1, restore-from-sync is a V1.5 P0 cross-repo TODO; until it ships,
the user's brain remote (with brain-sync enabled) holds curated artifacts
as markdown + git, recoverable manually via `gbrain import` from a clone.

---

## `/setup-gbrain --cleanup-orphans` (D20)

Re-collect a PAT (Step 4 path-2a scope disclosure), then:

```bash
# List user's Supabase projects (user has to pipe this through their own
# shell to review; we don't rely on a stored PAT).
export SUPABASE_ACCESS_TOKEN="<collected from read_secret_to_env>"
projects=$(curl -s -H "Authorization: Bearer $SUPABASE_ACCESS_TOKEN" \
  https://api.supabase.com/v1/projects)
```

Parse the response, identify any project named starting with `gbrain` whose
`ref` doesn't match the user's active `~/.gbrain/config.json` pooler URL.
For each orphan, AskUserQuestion per project: "Delete orphan project
`<ref>` (`<name>`, created `<created_at>`)?" — NEVER batch; per-project
confirm is a one-way door.

On confirmed delete:
```bash
curl -s -X DELETE -H "Authorization: Bearer $SUPABASE_ACCESS_TOKEN" \
  https://api.supabase.com/v1/projects/$REF
```

Never delete the active brain without a second explicit confirmation.

At end: `unset SUPABASE_ACCESS_TOKEN`. Revocation reminder.

---

## Telemetry (D4)

The preamble's Telemetry block logs skill success/failure at exit. When
emitting the event, add these enumerated categorical values to the
telemetry payload (SAFE — no free-form secrets, never the URL or PAT):

- `scenario`: `supabase-existing` | `supabase-auto-provision` |
  `supabase-manual` | `pglite-local` | `switch-to-supabase` |
  `switch-to-pglite` | `repo-flip-only` | `cleanup-orphans` |
  `resume-provision`
- `install_performed`: `yes` | `no` (D5 reuse) | `skipped` (pre-existing)
- `mcp_registered`: `yes` | `no` | `claude-missing`
- `trust_tier_set`: `read-write` | `read-only` | `deny` |
  `skip-for-now` | `n/a` (outside git repo)

Never pass `SUPABASE_ACCESS_TOKEN`, `DB_PASS`, `GBRAIN_POOLER_URL`,
`GBRAIN_DATABASE_URL`, or any `postgresql://` substring to the telemetry
invocation. The CI grep test in `test/skill-validation.test.ts` enforces
this at build time.

---

## Important Rules

- **One rule for every secret.** PAT, DB_PASS, pooler URL: env-var only,
  never argv, never logged, never persisted to disk by us. The only file
  that holds the pooler URL long-term is `~/.gbrain/config.json`, written
  by gbrain's own `init` at mode 0600 — that's gbrain's discipline, not
  ours.
- **STOP points are hard.** Gbrain doctor not healthy, D19 PATH shadow, D9
  migrate timeout, smoke test failure — each is a STOP. Do not paper over.
- **Concurrent-run lock.** At skill start, `mkdir ~/.gstack/.setup-gbrain.lock.d`
  (atomic). If the mkdir fails, abort with: "Another `/setup-gbrain` instance
  is running. Wait for it, or `rm -rf ~/.gstack/.setup-gbrain.lock.d` if
  you're sure it's stale." Release on normal exit AND in the SIGINT trap.
- **CLAUDE.md is the audit trail.** Always update it in Step 8 after a
  successful setup.