docs(setup): register the container-gateway hook per machine

docs/setup/secure-agent-setup.md

@@ -2864,7 +2864,7 @@ records which main checkout it confirmed the first time, under
 sandbox-writable; a later session that derives a different one is refused
 until you delete that record (the log line names it).
 
-Wire it as a `SessionStart` / `SessionEnd` pair in `~/.claude/settings.json`, alongside any other hooks already there, **by its absolute path** (your real home, `/home/<you>` on Linux). A `~` in a hook command is expanded from `$HOME` by the launching shell, and a session environment that redirects `$HOME` would run another script:
+Wire it as a `SessionStart` / `SessionEnd` pair in your user settings, alongside any other hooks already there, **by its absolute path** (your real home, `/home/<you>` on Linux). A `~` in a hook command is expanded from `$HOME` by the launching shell, and a session environment that redirects `$HOME` would run another script. Because that path is per-machine, it goes in `~/.claude/settings.local.json` when your `~/.claude/settings.json` is [synced across machines](#syncing-user-scope-config-across-machines) — a `/Users/<you>/...` path synced to a Linux box points at nothing, and the gateway never starts there; otherwise `~/.claude/settings.json` is fine. Claude Code merges hooks from both files:
 
 ```jsonc
 {
@@ -2879,6 +2879,17 @@ Wire it as a `SessionStart` / `SessionEnd` pair in `~/.claude/settings.json`, al
 }
 ```
 
+**Fixing your other machines.** If the hook was registered in a synced `~/.claude/settings.json`, move it: delete the two `container-gateway-hook.sh` entries from the synced file (once, on any machine), then on **every** machine add them to its own `~/.claude/settings.local.json` with that machine's home:
+
+```bash
+jq --arg h "$(cd ~ && pwd -P)" '
+  .hooks.SessionStart += [{"hooks":[{"type":"command","command":($h+"/.claude/scripts/container-gateway-hook.sh start")}]}]
+  | .hooks.SessionEnd += [{"hooks":[{"type":"command","command":($h+"/.claude/scripts/container-gateway-hook.sh stop")}]}]
+' ~/.claude/settings.local.json > ~/.claude/settings.local.json.new && mv ~/.claude/settings.local.json.new ~/.claude/settings.local.json
+```
+
+`setup-isolated-setup-verify` (check 12a) and `setup-isolated-setup-update` flag a hook whose registered path does not exist on the machine they run on.
+
 Every setting that points something at a gateway socket needs that socket's **absolute** path, which is per-machine, so the whole project-settings block belongs in the gitignored `.claude/settings.local.json` — nothing is committed.
 Add it by hand, substituting your own project's absolute path for `<project>` — nothing writes it for you.
 The gateway serves from the `run/` directory of the personal config layer:
@@ -3214,6 +3225,8 @@ Three reasons make this non-negotiable:
 Public dotfile repos are fine for shell aliases and editor configs;
 they are the wrong shape for agent-runtime files.
 
+**Per-machine entries stay out of the synced file.** Anything that names an absolute path under your home — the container gateway's `SessionStart` / `SessionEnd` hooks above, a pinned interpreter, socket paths — differs between macOS (`/Users/<you>`) and Linux (`/home/<you>`). Keep those in each machine's `~/.claude/settings.local.json`, which is never synced; Claude Code merges hooks and settings from both files.
+
 ## Adopter setup
 
 If you are adopting the framework into your own tracker repo, copy
@@ -3601,11 +3614,13 @@ below and report ✓ done / ✗ missing / ⚠ partial, with the evidence
     and the `gh tofile` alias workaround).
 12. **Container gateway wired.** Only meaningful when `podman` or
     `docker` is on `PATH`; report n/a otherwise. Four things:
-    - User-scope `~/.claude/settings.json` has a `SessionStart`
-      hook running `container-gateway-hook.sh start` and a
-      `SessionEnd` hook running `container-gateway-hook.sh stop`,
-      and `~/.claude/scripts/container-gateway-hook.sh` exists and
-      is executable.
+    - User-scope `~/.claude/settings.json` or
+      `~/.claude/settings.local.json` has a `SessionStart` hook
+      running `container-gateway-hook.sh start` and a `SessionEnd`
+      hook running `container-gateway-hook.sh stop`, by an absolute
+      path that exists on this machine (✗ if it names another
+      machine's home), and `~/.claude/scripts/container-gateway-hook.sh`
+      exists and is executable.
     - The project `.claude/settings.json` or
       `.claude/settings.local.json` has `env.CONTAINER_HOST` and
       `env.DOCKER_HOST`, and both gateway sockets appear in

plugins/magpie-setup/skills/isolated-setup-install/optional-steps.md

@@ -177,13 +177,18 @@ until you delete that record (the log line names it).
 
 **L.2 — Hooks.** Wire a `SessionStart` hook running
 `container-gateway-hook.sh start` and a `SessionEnd` hook running
-`container-gateway-hook.sh stop` into `~/.claude/settings.json`, each
+`container-gateway-hook.sh stop` into the user settings, each
 **by the script's absolute path** with the home directory written out (a `~`
 there is expanded from `$HOME`, which the session environment can redirect),
 executed directly rather than through `bash`/`sh` (its `#!/bin/bash -p`
 shebang keeps `BASH_ENV` and exported functions out) —
 merging into existing arrays with a diff the operator approves,
-exactly as for K.2's touch-overlay hooks.
+exactly as for K.2's touch-overlay hooks. The file is
+`~/.claude/settings.local.json` when `~/.claude/settings.json` is a link
+into a synced config repo (the absolute path differs per machine;
+macOS `/Users/<you>`, Linux `/home/<you>`), and `~/.claude/settings.json`
+otherwise. If a synced file already carries the two entries, propose moving
+them, per the setup guide's "Fixing your other machines".
 
 **L.3 — Project wiring.** Propose the `env` block
 (`CONTAINER_HOST` / `DOCKER_HOST`) and the `allowUnixSockets` pair

plugins/magpie-setup/skills/isolated-setup-update/SKILL.md

@@ -18,7 +18,7 @@ when_to_use: >-
 capability: capability:platform
 surface_hash: sha256:1f327e069312dad2
 license: Apache-2.0
-measured_tokens: 6557
+measured_tokens: 6705
 ---
 
 <!-- Placeholder convention (see AGENTS.md#placeholder-convention-used-in-skill-files):
@@ -171,6 +171,9 @@ Walk each:
    - **`~/.local/share/uv` writable, or no host-only uv cache.**
      Earlier defaults put `~/.local/share/uv/` in `allowWrite`, where the interpreters and tool venvs that hooks, MCP servers and the excluded `uvx` / `uv run` commands run outside the sandbox live; and `uvx` ran from the shared, sandbox-writable `~/.cache/uv`.
      Report a write grant covering `~/.local/share/uv`, a `~/.config/uv/uv.toml` without an absolute host `cache-dir`, a missing `Read(~/.config/uv/uv.toml)` / `Edit(~/.config/uv/**)` / `Edit(~/.cache/prek/**)` deny, or an `env.PREK_HOME` that is missing or overlaps `~/.cache/prek`, as a **must-fix**; the remedy is `setup-isolated-setup-install` Step U ([Host-only uv state](../../../../docs/setup/secure-agent-setup.md#host-only-uv-state)).
+   - **A container-gateway hook registered for another machine.**
+     The `SessionStart` / `SessionEnd` hooks run `container-gateway-hook.sh` by its absolute path, which differs between macOS (`/Users/<you>`) and Linux (`/home/<you>`).
+     Report a registered path that does not exist on this machine as a **must-fix** (the gateway never starts), and one in a `~/.claude/settings.json` that links into a synced config repo as drift; the remedy is the setup guide's [Fixing your other machines](../../../../docs/setup/secure-agent-setup.md#container-gateway): move the entries into each machine's `~/.claude/settings.local.json`.
    - **`enableWeakerNetworkIsolation: true`.**
      It is not there for lychee, which runs offline.
      It lets native-TLS CLI tools verify TLS through the sandbox's TLS-terminating proxy — the mechanism the schema notes for `gh` / `gcloud` / `terraform`.

plugins/magpie-setup/skills/isolated-setup-verify/conditional-checks.md

@@ -259,10 +259,14 @@ reading this file; read the section for a check whose condition holds.
     for the whole check. Four sub-checks:
 
     - **12a — hooks wired.** User-scope `~/.claude/settings.json`
-      has a `SessionStart` hook running
-      `container-gateway-hook.sh start` and a `SessionEnd` hook
-      running `container-gateway-hook.sh stop`. Either missing is
-      ✗; a hook command naming the script through `~` or `$HOME`
+      or `~/.claude/settings.local.json` has a `SessionStart` hook
+      running `container-gateway-hook.sh start` and a `SessionEnd`
+      hook running `container-gateway-hook.sh stop`. Either missing is
+      ✗, and so is a registered absolute path that does not exist on
+      this machine (synced from another one, e.g. `/Users/...` on
+      Linux): point at the setup guide's "Fixing your other machines".
+      An absolute path in a `~/.claude/settings.json` that links into a
+      synced config repo is ◐: it breaks on the next machine; a hook command naming the script through `~` or `$HOME`
       rather than its absolute path is ◐ (the launching shell expands
       it from `$HOME`, which the session environment can redirect),
       and so is one that runs it through `bash`/`sh` rather than