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Cross-machine memory with GBrain sync
gstack writes a lot of useful state to ~/.gstack/ — learnings, retros, CEO
plans, design docs, developer profile. By default, all of that dies when you
switch laptops. GBrain sync pushes a curated subset to a private git
repo so your memory follows you across machines and becomes indexable by
GBrain.
What you get
- Work on machine A, pick up seamlessly on machine B.
- Your learnings, plans, and designs are visible in GBrain (if you use it).
- A clean off-ramp (
gstack-brain-uninstall) that never touches your data. - No daemon, no system service, no background process.
What does NOT leave your machine
By design, these stay local even when sync is on:
- Credentials:
.auth.json,auth-token.json,sidebar-sessions/,security/device-salt - Machine-specific state: Chromium profiles, ONNX model weights,
caches, eval-cache, CDP-profile, one-time prompt markers
(
.welcome-seen,.telemetry-prompted,.vendoring-warned-*, etc.) - Question-preferences: per-machine UX preferences
(
question-preferences.json,question-log.jsonl,question-events.jsonl).
The exact allowlist lives in ~/.gstack/.brain-allowlist. The CLI manages
it; you can append your own entries below the marker line.
First-run setup (30–90 seconds)
gstack-artifacts-init
The command:
- Turns
~/.gstack/into a git repo. - Asks for a remote URL (default:
gh repo create --private gstack-artifacts-$USER). Any git remote works — GitHub, GitLab, Gitea, self-hosted. - Pushes an initial commit with just the config.
- Writes
~/.gstack-artifacts-remote.txt(URL-only, no secrets — safe to copy to another machine). - Prints the
gbrain sources addhookup command for the brain host (never auto-executed — run it yourself, or on your own machinebin/gstack-gbrain-source-wireupdoes the same wiring) sogbrain searchcan index your synced learnings, plans, and designs. The oldgstack-brain-reader add --ingest-url ...HTTP path was removed in v1.15.1.0 — it depended on a/ingest-repoendpoint gbrain never shipped.
After init, the next skill you run will ask you ONE question about privacy mode:
- Everything allowlisted (recommended): learnings, reviews, plans, designs, retros, timelines, and developer profile all sync.
- Only artifacts: plans, designs, retros, learnings — skip behavioral data (timelines, developer profile).
- Decline: keep everything local. You can turn sync on later with
gstack-config set artifacts_sync_mode full.
Your answer is persisted. You won't be asked again.
Cross-machine workflow
On machine A: run gstack-artifacts-init once. That's it — every skill
invocation now drains the sync queue at its start and end boundaries
(~200–800 ms network pause per skill).
On machine B:
- Copy
~/.gstack-artifacts-remote.txtfrom machine A to machine B (password manager, dotfile repo, USB stick — your call; the legacy~/.gstack-brain-remote.txtname is still recognized). - Run any gstack skill. The preamble sees the URL file and prints:
BRAIN_SYNC: brain repo detected: <url> BRAIN_SYNC: run 'gstack-brain-restore' to pull your cross-machine memory - Run
gstack-brain-restore. That clones the repo, rehydrates your learnings/plans/retros, and re-registers the git merge drivers. - Next skill: your yesterday-on-machine-A learning surfaces. That's the magical moment.
Status, health, and queue depth
gstack-brain-sync --status
Shows: last successful push, pending queue depth, any sync blocks, and the current privacy mode.
Every skill run prints a BRAIN_SYNC: line near the top of the preamble
output. Scan it for problems.
Privacy modes in detail
| Mode | What syncs |
|---|---|
off |
Nothing (default). |
artifacts-only |
Plans, designs, retros, learnings, reviews. Skips timelines + developer-profile. |
full |
Everything in the allowlist, including behavioral state. |
Change anytime with:
gstack-config set artifacts_sync_mode full
gstack-config set artifacts_sync_mode off
Secret protection
Every commit is scanned for credential-shaped content before it leaves your machine. Blocked patterns include:
- AWS access keys (
AKIA…) - GitHub tokens (
ghp_,gho_,ghu_,ghs_,ghr_,github_pat_) - OpenAI keys (
sk-…) - PEM blocks (
-----BEGIN …-----) - JWTs (
eyJ…) - Bearer tokens in JSON (
"authorization": "…","api_key": "…", etc.)
If a scan hits, sync stops, the queue is preserved, and your preamble prints:
BRAIN_SYNC: blocked: <pattern-family>:<snippet>
To remediate:
- Review the offending file.
- If the match is a false positive on content you explicitly want to
sync, run
gstack-brain-sync --skip-file <path>to permanently exclude that path. - Otherwise, edit the file to remove the secret and re-run any skill.
There's a defense-in-depth hook at ~/.gstack/.git/hooks/pre-commit that
runs the same scan if you manually git commit against the repo.
Separately (v1.63.0.0+), every push writes a tamper-evident receipt to the
egress ledger (~/.gstack/security/egress.jsonl) before anything is
sent, fail-closed: if the receipt can't be written, the push is refused
and the queue is preserved. Inspect the ledger with gstack-egress list
and verify its hash chain with gstack-egress verify.
Two-machine conflicts
If you write on machine A and machine B the same day, both will push
append commits. Git's default would conflict at the file tail, but the
.jsonl and markdown files are registered with custom merge drivers:
- JSONL files use a sort-and-dedup driver that orders appends by ISO timestamp (falls back to SHA-256 hash of each line for determinism).
- Markdown artifacts (retros, plans, designs) use a union merge driver that concatenates both sides.
You shouldn't see conflict prompts. If you do (a real semantic conflict, like two machines editing the same plan), git will stop and prompt.
Cross-machine pull cadence
The preamble runs git fetch + git merge --ff-only once per 24 hours
(cached via ~/.gstack/.brain-last-pull). You don't need to think about
this — it happens automatically at the first skill invocation each day.
Uninstall
gstack-brain-uninstall
This:
- Removes
~/.gstack/.git/and all.brain-*config files. - Clears
artifacts_sync_modeingstack-config. - Does NOT touch your learnings, plans, retros, or developer profile.
Add --delete-remote to also delete the private GitHub repo (GitHub only,
uses gh repo delete).
Re-init anytime with gstack-artifacts-init.
Troubleshooting
See gbrain-sync-errors.md for an index of every error message gstack-brain may print, with problem / cause / fix for each.
Under the hood
The architectural decisions behind this feature: allowlist over denylist (unknown files stay local by default), preamble-boundary sync over a daemon (no background process to babysit), a JSONL merge driver so concurrent machines union their queues instead of conflicting, and a privacy stop-gate that asks once before anything syncs.