diff --git a/docs/solutions/architecture-patterns/git-sync-secret-exposure-and-tracked-file-boomerang.md b/docs/solutions/architecture-patterns/git-sync-secret-exposure-and-tracked-file-boomerang.md
new file mode 100644
index 0000000..451a3ac
--- /dev/null
+++ b/docs/solutions/architecture-patterns/git-sync-secret-exposure-and-tracked-file-boomerang.md
@@ -0,0 +1,243 @@
+---
+title: "Secret exposure under bidirectional Grav git-sync: gitignore is the only boundary (and the tracked-file boomerang trap)"
+date: 2026-07-05
+module: git-sync
+problem_type: architecture_pattern
+component: tooling
+severity: high
+category: architecture-patterns
+applies_when:
+  - "Enabling bidirectional Grav git-sync (direction: both, on_save: true) so prod can push content back to Gitea"
+  - "Auditing whether the server can leak secrets (tokens, password hashes, signing salts) off the production host"
+  - "A per-install runtime-generated value is being persisted into a tracked config file that also carries functional config"
+  - "Deciding where a per-install secret must live so it never round-trips"
+  - "A config value keeps ping-ponging or re-committing itself across environments after each sync"
+tags:
+  - git-sync
+  - secret-exposure
+  - gitignore
+  - grav
+  - popularity-salt
+  - config-boundary
+  - bidirectional-sync
+  - per-install-secret
+  - env-tree-leak
+---
+
+# Secret exposure under bidirectional Grav git-sync: gitignore is the only boundary (and the tracked-file boomerang trap)
+
+> **Correction (2026-07-05):** An earlier version of this doc claimed the sync
+> add-set was *scoped to the configured `folders`*, and concluded that
+> `accounts/` and `user/env/` were "safe by construction" because they sit
+> outside `pages/config/themes`. **That model is wrong and caused a live secret
+> leak.** git-sync's auto-commit stages files **outside** the configured folders;
+> the only reliable exclusion is `.gitignore`. The corrected model is below.
+
+## Context
+
+The intotheeast.com Grav site runs the `git-sync` plugin on production in
+**bidirectional** mode: `direction: both`, `on_save: true`, a webhook at
+`/_git-sync`, and configured `folders: pages, config, themes`. Bidirectional
+means the server both *pulls* content authored elsewhere **and** *pushes*
+content authored on the server (Admin edits, `/post` submissions, uploads) back
+to the shared Gitea repo.
+
+The operator's question was: **"Can I safely enable bidirectional prod → Gitea
+sync without leaking secrets?"** Production holds things that must never reach a
+shared repo — API tokens, JWT signing secrets, CSRF salts, the git-sync token
+itself.
+
+The dangerous, tempting answer is "the plugin only syncs `pages/config/themes`,
+so anything outside those folders is safe." **This is false, and acting on it
+leaked secrets.** See the incident below.
+
+## The incident (what actually happened)
+
+Production's git-sync auto-commit `9337003` ("(Grav GitSync) Automatic Commit
+...") pushed the **entire `user/env/intotheeast.com/config/` tree** to Gitea —
+including `api-private.php` (JWT secret), `security-private.php` (CSRF salt), and
+`git-sync.yaml` (the sync **token + webhook secret**) — plus `accounts/mischa.yaml`
+(password hash), `system.yaml`, and `post-form.md`.
+
+**None of those paths is under the configured `folders: pages, config, themes`.**
+`user/env/` is a sibling of `user/config/`, not a subfolder of it. Yet git-sync
+staged and pushed them anyway. That single fact refutes the "folders scope the
+add-set" model empirically: **the `folders` setting does not scope what the
+auto-commit stages.** Whatever git-sync's exact `git add` invocation, the
+operational truth is that its commit sweeps the whole `user/` working tree.
+
+Remediation: disable sync → `.gitignore` `/env/` and `git rm --cached` it →
+`reset --hard` prod to the gitignored state → regenerate the leaked JWT/CSRF
+salts (delete the `*-private.php` files; Grav regenerates them) → **rotate the
+Gitea token and webhook secret** (they were exposed in `git-sync.yaml`). Rotation
+is what actually neutralizes the leak; the history rewrite is optional for a
+private repo.
+
+## Guidance
+
+The safety question reduces to one predicate — but **not** the one the original
+doc used:
+
+> **A file round-trips to the shared repo if and only if it is NOT gitignored.**
+> The configured `folders` setting does **not** narrow this. Treat the
+> round-trippable set as *everything under `user/` that git will track* — i.e.
+> everything not matched by `user/.gitignore`.
+
+Consequences, corrected:
+
+1. **`.gitignore` is the only reliable boundary.** Do not rely on a file being
+   "outside the synced folders." If it is under `user/` and not gitignored, a
+   bidirectional sync can push it. Design exclusions with `.gitignore`, and
+   verify with `git -C user status` / `git -C user check-ignore <path>`.
+
+2. **`accounts/` is NOT structurally excluded.** `user/accounts/*.yaml` (bcrypt
+   password hashes) is a *tracked* content folder and is not gitignored, so it
+   **does** round-trip — `accounts/mischa.yaml` was in the leak commit. If you
+   need an account file to stay server-local, it must be gitignored explicitly
+   (as `accounts/testrunner.yaml` already is). The earlier "password hashes never
+   leave the server" claim was wrong.
+
+3. **The per-environment tree `user/env/<host>/` MUST be gitignored** — it is
+   **not** inherently safe. It holds the live git-sync token, JWT secret, and
+   CSRF salt (Grav writes all server-side Admin config there once the env dir
+   exists). Because it is not under `user/config/` people assumed it was outside
+   the sync scope; the incident proved it is not. It is now gitignored
+   (`/env/` in `user/.gitignore`, commit `6e8eadb`). Keep it that way.
+
+   > Side effect worth remembering: once `user/env/<host>/` exists, Grav's Admin
+   > writes **all** config changes there (system and plugin), not into
+   > `user/config/`. So server-side Admin edits are server-only — but "server-only"
+   > now depends entirely on `/env/` being gitignored, not on folder scope. When
+   > auditing, check **both** `user/config/...` and `user/env/<host>/config/...`
+   > (env wins at runtime). See `docs/working/git-sync-notes.md`.
+
+4. **Per-install secrets go in gitignored companion files.** Grav's convention
+   splits a per-install secret out of the functional YAML into a sibling that is
+   gitignored: the JWT secret in `api-private.php`, the CSRF/nonce + rate-limit
+   salt in `security-private.php`, plus `security.yaml` and `versions.yaml`.
+   These are safe **because they are gitignored**, not because of where they sit.
+
+Run every secret through predicate #1 (is it gitignored?) and the answer falls
+out — but you must actually enumerate what is *not* gitignored, not what is
+"outside the folders."
+
+### The tracked-file boomerang (a separate trap)
+
+Independently of the folder-scope error above, there is a second trap that the
+original doc got right and that still holds: **a per-install value that a plugin
+regenerates at runtime and persists into a tracked, functional config file.**
+
+The concrete case: the `api` plugin's *popularity* feature generates
+`popularity.salt` and writes it **into `user/config/plugins/api.yaml`** — a file
+that also carries must-be-shared functional config. That file is tracked, so on
+prod the popularity feature regenerates the salt, git-sync stages the change,
+commits, and **pushes prod's salt back to the shared repo**. Another environment
+pulls it, regenerates *its own* salt, pushes again. The value **ping-pongs across
+installs**, producing endless noise commits.
+
+The critical realization: **you cannot gitignore a single key inside a file that
+also carries functional config.** `.gitignore` operates on whole files. `api.yaml`
+must be tracked because the rest of it must be shared; therefore the salt inside
+it is tracked too; therefore it boomerangs.
+
+### The rules
+
+For any per-install runtime-generated value, pick one of exactly three
+resolutions — and do **not** reach for the fourth (stripping the line), which
+cannot work under sync:
+
+- **Isolate the value into a gitignored companion `<name>-private.php`** — the
+  pattern Grav uses for the JWT secret via `api-private.php`.
+- **Disable the feature that generates it** (e.g. `popularity.enabled: false`).
+- **Consciously accept the churn** when the value is genuinely low-stakes
+  (`popularity.salt` is an IP-hashing salt, not a credential).
+
+Do **not** keep stripping the value from the tracked file — bidirectional sync
+brings it right back on the next save.
+
+### Before / after: what sticks and what doesn't
+
+**A standalone file gitignored + untracked sticks.** For `security-private.php`
+(a file that contains *only* the secret) or the whole `user/env/` tree:
+
+```bash
+git -C user rm --cached -r config/security-private.php   # or: rm --cached -r env
+printf '/config/security-private.php\n/env/\n' >> user/.gitignore
+```
+
+This works permanently. The path is no longer tracked, so the sync's add-set
+skips it forever. The fix sticks because the secret owns its own gitignored path.
+
+**A key inside a tracked functional file — stripping the line does NOT stick.**
+For `popularity.salt` inside `api.yaml`, deleting just the `salt:` line and
+committing looks clean locally, but Grav re-appends it at runtime and the next
+sync re-commits and re-pushes it. The only durable fixes are the
+companion-private-file pattern or disabling the feature.
+
+## Why This Matters
+
+Two quiet, cross-environmental failure modes:
+
+1. **The folder-scope illusion.** Assuming "only `pages/config/themes` sync" is a
+   security control leads you to leave secrets in `env/` or `accounts/` unignored
+   — and a single Admin save on prod pushes them to a shared repo. This actually
+   happened here. The only defensible mental model is *gitignore is the boundary*;
+   enumerate the un-ignored set, not the "un-foldered" set.
+
+2. **The boomerang.** A "cleanup" commit that strips a secret from a *tracked*
+   file looks done locally but silently reappears upstream on the next content
+   save, because the plugin regenerates it and the sync re-commits it.
+
+Getting both right is what lets you answer "is bidirectional sync safe?" honestly.
+The answer is **yes, once `user/.gitignore` actually excludes every sensitive
+path** — `env/`, the per-install `*-private.php` files, `security.yaml`,
+`versions.yaml`, and any account file that must stay server-local — and once every
+runtime-regenerated value either lives in its own gitignored file or is a
+consciously-accepted low-stakes churn. It is emphatically **not** safe on the
+strength of folder scoping alone.
+
+## When to Apply
+
+- **Enabling or auditing bidirectional git-sync** on a server that authors
+  content. Enumerate the round-trippable set as *everything under `user/` not
+  matched by `.gitignore`* — then confirm no secret is in it.
+- **Deciding where a new secret or per-install generated value should live.**
+  Standalone gitignored file for anything sensitive; never a key inside a shared
+  functional YAML; never "outside the folders" as the sole justification.
+- **Reviewing a "stop tracking this secret" cleanup** for whether it will stick:
+  is the secret in its own gitignored path (holds) or a line inside a tracked
+  functional file that something regenerates (boomerangs)?
+
+## Examples
+
+**The leak (what "folder scope is safe" cost).** With `folders: pages, config,
+themes` and `/env/` **not** gitignored, prod's auto-commit `9337003` pushed
+`user/env/intotheeast.com/config/**` (JWT, CSRF salt, git-sync token + webhook
+secret), `accounts/mischa.yaml`, `system.yaml`, and `post-form.md` to Gitea —
+all outside the configured folders. Fix: gitignore + untrack `/env/`, regenerate
+the JWT/CSRF salts, **rotate the token and webhook secret**.
+
+**Safe after remediation.** Same bidirectional config, but now `user/.gitignore`
+excludes `/env/`, `config/plugins/git-sync.yaml`, `config/plugins/api-private.php`,
+`config/security.yaml`, `config/security-private.php`, `config/versions.yaml`.
+Running each secret through *is-it-gitignored*: all sensitive paths are excluded →
+none is in the round-trippable set. Verified: prod's `git status` shows only the
+intended tracked content, and no boomerang/secret commit lands on the remote.
+
+**Boomerang example.** `popularity.salt` in the tracked `api.yaml` regenerates
+per-install and re-commits under sync. The fix that *sticks* is the
+companion-private-file pattern or `popularity.enabled: false` — **not** stripping
+the `salt:` line.
+
+## Related
+
+- `docs/solutions/conventions/grav-plugin-config-must-be-tracked-override.md` — the
+  origin of the "functional plugin config in tracked `user/config/plugins/`,
+  secrets/per-install values in gitignored `*-private.php`" rule. That doc covers
+  *where config must live to deploy*; this doc covers *why gitignore — not folder
+  scope — is the sync boundary, and why a runtime-written tracked value boomerangs*.
+- `docs/working/git-sync-notes.md` — operational notes on git-sync's synced
+  folders and the per-environment tree. Corrected in the same 2026-07-05 pass to
+  drop the "env/ is outside the sync scope so it's safe" claim.
+- `docs/solutions/integration-issues/stale-grav-version-blocks-api-plugin-install.md`
+  — adjacent context from the same Grav production cutover, different failure mode.
diff --git a/docs/solutions/conventions/grav-plugin-config-must-be-tracked-override.md b/docs/solutions/conventions/grav-plugin-config-must-be-tracked-override.md
index 36df1f7..731d0b0 100644
--- a/docs/solutions/conventions/grav-plugin-config-must-be-tracked-override.md
+++ b/docs/solutions/conventions/grav-plugin-config-must-be-tracked-override.md
@@ -82,4 +82,5 @@ The failure is silent and per-environment: it works on the developer's machine (
 
 - `docs/solutions/integration-issues/stale-grav-version-blocks-api-plugin-install.md` — the config gap documented here was the *other* latent problem surfaced in that same investigation: the `api` plugin also had to be *installed* first before any config could take effect. The install gap (GPM version floor) and this config-tracking gap compounded each other on the fresh prod environment.
 - `docs/working/git-sync-notes.md` — the related third config location: on prod, Grav Admin saves config into the per-environment tree `user/env/<host>/config/`, which is *also* untracked. Same "config that doesn't reach the repo" family.
+- `docs/solutions/architecture-patterns/git-sync-secret-exposure-and-tracked-file-boomerang.md` — the sync-boomerang consequence of this rule: a per-install value that a plugin regenerates into a *tracked* functional config file (e.g. `popularity.salt` in `api.yaml`) re-commits itself and ping-pongs across environments under bidirectional git-sync. The `*-private.php` companion pattern this doc establishes is exactly the durable fix.
 - **CLAUDE.md §0 (plugin-management model):** only `pages/`, `config/`, `accounts/`, `themes/` are tracked in the `user/` repo; `plugins/` and `data/` are gitignored and GPM-managed. That tracking boundary is exactly why functional config must live under `config/plugins/`, not in the plugin's own folder.
diff --git a/docs/working/git-sync-notes.md b/docs/working/git-sync-notes.md
index b1c5045..473a427 100644
--- a/docs/working/git-sync-notes.md
+++ b/docs/working/git-sync-notes.md
@@ -16,12 +16,17 @@ user/config/plugins/git-sync.yaml                       ← NOT here
 
 Why this matters:
 
-- **Server-only, not synced, not committed.** `user/env/` is outside the
-  content repo's tracked folders (`pages`/`config`/`accounts`/`themes`) and is
-  not one of git-sync's synced folders (`pages`/`config`/`themes`). So config
-  saved via Admin *on the server* never reaches Gitea or local. This is ideal
-  for the git-sync token (it stays server-only) but means **prod Admin config
-  edits silently diverge** — author durable config in the repo, not prod Admin.
+- **⚠️ `user/env/` is NOT safe unless gitignored — it is NOT scoped out by the
+  `folders` setting.** An earlier version of this note claimed `user/env/`
+  "never reaches Gitea" because it is outside git-sync's synced folders. **That
+  is wrong and caused a live secret leak (2026-07-05).** git-sync's auto-commit
+  stages files *outside* the configured `folders`; on prod it pushed the whole
+  `user/env/intotheeast.com/config/` tree — JWT secret, CSRF salt, **and the
+  git-sync token + webhook secret** — to Gitea. The fix was to **gitignore
+  `/env/`** (commit `6e8eadb`). So: prod Admin config edits stay server-only
+  *only because `/env/` is now gitignored*, not because of folder scope. Author
+  durable config in the repo, not prod Admin. Full analysis:
+  `docs/solutions/architecture-patterns/git-sync-secret-exposure-and-tracked-file-boomerang.md`.
 - **Look in both places.** When inspecting/toggling server config, check
   `user/config/plugins/<name>.yaml` **and**
   `user/env/<host>/config/plugins/<name>.yaml` (env wins).
@@ -48,19 +53,25 @@ If you see the comma-string form on an older version, fix it by editing
 `git-sync.yaml` directly (at whichever path it lives — see above); do not
 re-save folders via the Admin UI on the buggy version.
 
-## Per-install / secret files — must be gitignored (never synced)
+## Per-install / secret files — must be gitignored (gitignore is the boundary)
 
-git-sync syncs the `config/` folder, so any per-install or secret file tracked
-there would get pushed to Gitea and pollute every environment. Keep these out
-of the content repo (all in `user/.gitignore`):
+git-sync's auto-commit stages **everything under `user/` that is not
+gitignored** — the `folders` setting does *not* scope the commit add-set (a
+2026-07-05 leak proved this by pushing `user/env/**`, outside the configured
+folders). So `.gitignore` — not folder scope — is the only thing keeping a
+per-install or secret file off Gitea. Keep all of these gitignored in
+`user/.gitignore`:
 
-| File | Why |
+| Path | Why |
 |---|---|
+| `env/` | **whole per-host env tree** — holds the live git-sync token, JWT secret, CSRF salt + all server-side Admin config. Gitignored + untracked 2026-07-05 (commit `6e8eadb`) after it leaked to Gitea. NOT safe on folder scope alone. |
 | `config/plugins/git-sync.yaml` | encrypted token; server-specific (also lives at env path on prod) |
 | `config/plugins/api-private.php` | API JWT secret |
 | `config/security.yaml` | Grav nonces/salts (legacy location) |
 | `config/versions.yaml` | per-install Grav schema-migration state — differs per env (dev 2.0.4, prod 2.0.7); Grav regenerates it. Untracked 2026-07-04. |
-| `config/security-private.php` | **TODO:** committed salt secret; should be gitignored like `api-private.php` (deferred — untracking resets server sessions) |
+| `config/security-private.php` | CSRF/nonce + admin rate-limit signing salt; gitignored + untracked 2026-07-05 (commit 2840018). Each env keeps its own; untracking regenerates prod's salt (one-time admin re-login). |
+
+> **Why a key inside a *tracked* config file (e.g. `popularity.salt` in `api.yaml`) can't just be stripped** — it regenerates at runtime and boomerangs back via git-sync's `git add -A`. See `docs/solutions/architecture-patterns/git-sync-secret-exposure-and-tracked-file-boomerang.md` for the full round-trippable-set model.
 
 ## git-sync config summary (prod, 2026-07-04)