feat: bake shellcheck and add a client-side pre-push lint gate

v1.8.14 made shell lint a RELEASE gate (scripts/lint-shell.sh, shared by lint.yml
and the new lint-gate job that resolve-versions depends on), and that script
correctly exits 2 when shellcheck is absent -- "a gate that cannot run must not
pass". Measured on v1.8.14 on 2026-09-09 by three routes (command -v, dpkg -l, a
filesystem search): shellcheck was NOT IN THE IMAGE AT ALL. So the gate could not
be run by a developer in any container, only in CI, and the loop stayed
write-shell -> push -> wait for CI -> discover. That is the loop the gate was
added to shorten, after v1.8.14's first attempt burned ~46 min on a tree whose
lint had already been red for 24 hours.

shellcheck 0.10.0-1 added to the Dockerfile.base apt block: ~39 MB installed
(Installed-Size 40112 KB), measured to pull ZERO additional packages under
--no-install-recommends because libc6/libffi8/libgmp10 are already present.
NOTE this forces one full base rebuild -- base-decide hashes Dockerfile.base +
rootfs/, so unlike a scripts/ change it cannot reuse the existing base- layer.

hooks/pre-push is opt-in per clone (git config core.hooksPath hooks), bypassable
with --no-verify, and execs scripts/lint-shell.sh rather than reimplementing it
-- one copy, because a duplicated check that drifts is the failure this repo
keeps paying for. Matches the idiom skillset/ and myconfigs/ already use.

WHY THIS REPO HAD NO HOOKS, since it was reported as drift and is not: a peer
asked tor-ms22 for core.hooksPath per clone on the premise that unset meant the
gates were unverified there. Measured: pi-devbox unset, skillset hooks, myconfigs
common/hooks, pi-toolkit unset -- but `git ls-files | grep -i hook` is EMPTY in
both pi-devbox and pi-toolkit, so there was nothing to point at on any machine
and unset was the only correct value. This closes the real half for pi-devbox;
pi-toolkit still ships none.

Verified, expected result written down before each check:
  * refusal paths -- shellcheck absent => rc 2 with the remedy named; linter
    missing => rc 2. Never waved through on the assumption CI will catch it.
  * the hook is IN the scan set -- "Checking 14 shell file(s)" with it present,
    13 with it moved aside, so the extensionless file is found by the shebang
    half of the linter's two-signal union. This check exists because the first
    attempt was ambiguous: a planted `[ $UNSET_VAR = "x" ]` was not reported,
    which could equally have meant "not scanned" or "below -S error". It was the
    latter. A count that moves is unambiguous; a clean run is not.
  * it catches the REAL v1.8.14 defect -- planting `echo 'the fleet\'s thing'`
    in hooks/pre-push yields SC1073/SC1072 at severity error, rc=1.

And the gate earned its keep inside this commit: the first version of the
smoke-test assertion carried a comment beginning "# shellcheck is a GATE
DEPENDENCY", and a comment whose first word is the tool's name is parsed as a
DIRECTIVE, not a comment. The new gate failed it with SC1073/SC1072 before the
push -- same family as the v1.8.14 apostrophe, a line that reads as prose to a
human and as syntax to the parser.

.env.example

@@ -87,6 +87,35 @@ SSH_KEY_PATH=~/.ssh
 # MEMPALACE_PI_REMOTE_PATH=/data/feed
 # MEMPALACE_PI_DEVICE=
 
+# ── Mailbox notification: MUST BE NAMED, auto-detect CANNOT work here ──
+# The mempalace extension polls the logstream for fleet asks addressed to this
+# device and queues them into the next turn. That part needs no config. The
+# NOTIFICATION that tells the human it happened does, and unset means SILENT
+# outside the pi TUI.
+#
+# Why there is no working default: terminal identity lives in env vars set by
+# the emulator (KITTY_WINDOW_ID, TERM_PROGRAM) and `docker exec` does NOT
+# forward them — inside the container pi sees only TERM=xterm-256color no matter
+# what is rendering it. So "desktop" auto-detection always falls through to
+# OSC 777, which Kitty does not implement, and the notification silently does
+# nothing: the worst outcome for a feature whose only job is to break a silence.
+# Naming the protocol is what makes it fire.
+#
+#   kitty    OSC 99 desktop notification (correct for Kitty, incl. over SSH)
+#   osc777   OSC 777 (tmux/iTerm2/foot and others)
+#   desktop  OSC 99 if KITTY_WINDOW_ID is visible, else OSC 777 — inside a
+#            container that means effectively always OSC 777, so prefer naming
+#   0 / off  suppress entirely (in-TUI notify still shows)
+# MEMPALACE_MAILBOX_NOTIFY=kitty
+#
+# Cadence, if the delivery ever feels late: the poll is coupled to session
+# activity (it runs when the agent settles), NOT to a wall clock.
+# MEMPALACE_MAILBOX_POLL_MS is therefore a FLOOR BETWEEN POLLS (default 300000),
+# not a promise of one every 5 minutes — an idle session polls zero times, and
+# session start does the first look.
+# MEMPALACE_MAILBOX_POLL_MS=300000
+# MEMPALACE_MAILBOX_RESURFACE_MS=3600000
+
 # ── LAN access from the container (host-OS-agnostic) ─────────────────
 # On VM-backed hosts (macOS OrbStack / Docker Desktop) the container can't
 # reach the host's directly-attached LAN peers by default. The entrypoint

.gitea/workflows/docker-publish.yml

@@ -157,7 +157,41 @@ jobs:
   # buildcache silently reuses the layer from whatever pi version was
   # current when the cache was first populated. Same class of bug as
   # pi-devbox v0.74.0..v0.75.5 (fixed in v0.75.5b 2026-05-23).
+  # ── release gate ──────────────────────────────────────────────
+  # Refuse to spend a base build on a tree whose own shell scripts do not lint.
+  #
+  # v1.8.14's first attempt is why this exists. smoke and smoke-studio both failed
+  # at scripts/smoke-test.sh:770 AFTER build-base had already spent ~46 minutes,
+  # on a defect shellcheck had flagged as SC2289 (severity error) a day earlier:
+  # the lint workflow went red on the very push that introduced it (run 186) and
+  # stayed red for runs 187 and 188, unread.
+  #
+  # lint.yml deliberately does not run on tag pushes, and its reasoning is sound
+  # (the tagged tree was already linted on main; a tag-ref lint run sorts above
+  # the publish run and makes a release look finished before anything ships). The
+  # missing invariant was never "lint the tag" -- it was "do not RELEASE a tree
+  # whose lint failed", and only a job inside THIS workflow can enforce that.
+  #
+  # ~40 s, ahead of everything expensive, and it runs scripts/lint-shell.sh --
+  # the same file lint.yml calls, not a second copy that drifts.
+  lint-gate:
+    runs-on: ubuntu-latest
+    container:
+      image: catthehacker/ubuntu:act-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install shellcheck
+        run: |
+          apt-get update
+          apt-get install -y --no-install-recommends shellcheck
+
+      - name: "Shellcheck + syntax-check repository scripts (severity: error)"
+        run: bash scripts/lint-shell.sh
+
   resolve-versions:
+    # Gated: a defective tree must not reach a 46-minute base build.
+    needs: [lint-gate]
     runs-on: ubuntu-latest
     container:
       image: catthehacker/ubuntu:act-latest
@@ -543,7 +577,12 @@ jobs:
         env:
           EXPECTED_PI_VERSION: ${{ needs.resolve-versions.outputs.pi_version }}
           EXPECTED_MEMPALACE_VERSION: ${{ needs.resolve-versions.outputs.mempalace_version }}
-        run: bash scripts/smoke-test.sh pi-devbox:smoke
+        run: |
+          # Single source of truth for the node major is Dockerfile.base's ARG.
+          # Asserting the BUILT image matches it also catches a stale cached layer.
+          EXPECTED_NODE_MAJOR=$(sed -n 's/^ARG NODE_VERSION=\([0-9][0-9]*\).*/\1/p' Dockerfile.base)
+          export EXPECTED_NODE_MAJOR
+          bash scripts/smoke-test.sh pi-devbox:smoke
 
   # ── Phase 3b: amd64 smoke for the studio variant ────────────────────
   # Additive + independent of the core `smoke` job: gates ONLY
@@ -606,7 +645,12 @@ jobs:
         env:
           EXPECTED_PI_VERSION: ${{ needs.resolve-versions.outputs.pi_version }}
           EXPECTED_MEMPALACE_VERSION: ${{ needs.resolve-versions.outputs.mempalace_version }}
-        run: bash scripts/smoke-test.sh pi-devbox:smoke-studio
+        run: |
+          # Single source of truth for the node major is Dockerfile.base's ARG.
+          # Asserting the BUILT image matches it also catches a stale cached layer.
+          EXPECTED_NODE_MAJOR=$(sed -n 's/^ARG NODE_VERSION=\([0-9][0-9]*\).*/\1/p' Dockerfile.base)
+          export EXPECTED_NODE_MAJOR
+          bash scripts/smoke-test.sh pi-devbox:smoke-studio
 
   # ── Phase 4: multi-arch publish ─────────────────────────────────────
   build-variant:

.gitea/workflows/lint.yml

@@ -75,31 +75,11 @@ jobs:
         # are shell scripts with no extension. -print0/mapfile -d '' so a path
         # with a space cannot silently split, and the file count is asserted
         # non-zero — a green tick over an empty file set is not a check.
-        run: |
+        #
-          # Union of two signals, because either alone misses a real case:
+        # The implementation moved to scripts/lint-shell.sh on 2026-09-08 so the
-          # a shebang scan misses a sourced fragment with no shebang, and a
+        # release gate in docker-publish.yml runs the SAME code rather than a
-          # *.sh glob misses the extensionless tools in rootfs/usr/local/bin/.
+        # second copy that drifts. Edit the script, not a copy of it.
-          # Silent skipping is precisely the failure mode this gate exists to
+        run: bash scripts/lint-shell.sh
-          # prevent, so err toward over-collecting.
-          mapfile -d '' -t all_files < <(find . -not -path './.git/*' -type f -print0)
-          sh_files=()
-          for f in "${all_files[@]}"; do
-            case "$f" in *.sh) sh_files+=("$f"); continue;; esac
-            if head -n1 "$f" 2>/dev/null | grep -qE '^#!.*\b(bash|sh)\b'; then
-              sh_files+=("$f")
-            fi
-          done
-          echo "Checking ${#sh_files[@]} shell file(s)"
-          if [ "${#sh_files[@]}" -eq 0 ]; then
-            echo "::error::no shell files found — the shebang scan or the checkout is wrong"
-            exit 1
-          fi
-          shellcheck -S error -f gcc "${sh_files[@]}"
-          rc=0
-          for f in "${sh_files[@]}"; do
-            bash -n "$f" || { echo "::error file=$f::bash -n failed"; rc=1; }
-          done
-          exit "$rc"
 
       - name: Gitea shell guard (catches the actionlint blind spot)
         # actionlint models GitHub Actions, where the default run shell is

CHANGELOG.md

@@ -11,6 +11,250 @@ Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
 
 ---
 
+## Unreleased
+
+**`shellcheck` is now in the image, because the release gate it depends on could
+not be run by anyone.** v1.8.14 made shell lint a release gate: `scripts/lint-shell.sh`
+became the single source of truth for `lint.yml` and a new `lint-gate` job that
+`resolve-versions` depends on, and it deliberately exits 2 when `shellcheck` is
+absent — *a gate that cannot run must not pass*. Measured on v1.8.14 on
+2026-09-09, by three routes (`command -v`, `dpkg -l`, a filesystem search):
+**`shellcheck` was not in the image at all.** So `bash scripts/lint-shell.sh`
+exited 2 in every devbox container, and the only place the gate could ever run
+was CI. The developer loop was therefore write-shell → push → wait for CI →
+discover — which is the loop the gate was added to shorten, after v1.8.14's first
+attempt burned ~46 minutes on a tree whose lint had already been red for 24
+hours. Added to the `apt-get` block in `Dockerfile.base`: `shellcheck 0.10.0-1`,
+~39 MB installed (`Installed-Size` 40112 KB), and measured to pull **zero**
+additional packages under `--no-install-recommends` because its three deps
+(`libc6`, `libffi8`, `libgmp10`) are already present. **This forces one full base
+rebuild** — `base-decide` hashes `Dockerfile.base` + `rootfs/`, so unlike a
+`scripts/` change it cannot reuse the existing `base-` layer.
+
+**A client-side pre-push lint gate: `hooks/pre-push`.** Opt-in per clone with
+`git config core.hooksPath hooks`, bypass with `git push --no-verify`, matching
+the idiom the `skillset` and `myconfigs` repos already use. It is a thin wrapper
+that `exec`s `scripts/lint-shell.sh` — the same script CI runs, one copy, because
+a duplicated check that drifts is the failure this repo keeps paying for (the
+`pi-extensions` skill mirror sat 9579 B behind for weeks; the shell-lint logic
+was extracted to one file for exactly this reason).
+
+> **Why this repo had no hooks at all, which is worth stating because it was
+> reported as drift and is not.** A fleet peer asked `tor-ms22` to report
+> `git config core.hooksPath` per clone on the premise that an unset value meant
+> "no secret-scan and no shell-lint hook locally", leaving the drift/secret gates
+> unverified. Measured: `pi-devbox` **unset**, `skillset` `hooks`, `myconfigs`
+> `common/hooks`, `pi-toolkit` **unset**. But `git ls-files | grep -i hook` is
+> **empty** in both `pi-devbox` and `pi-toolkit` — neither repo tracked a single
+> hook file, so there was nothing for `core.hooksPath` to point at on any machine
+> and unset was the only correct value. The two repos that do ship hooks were
+> already wired correctly. This entry closes the real half of that gap for
+> `pi-devbox`; `pi-toolkit` still ships none.
+
+**The hook is verified to catch the defect that motivated it, not merely to
+exist.** Three measurements, each with the expected result written down first:
+
+- **Refusal paths.** With `shellcheck` absent (the state of every container built
+  before this change) the hook exits **2** and names the remedy; with
+  `scripts/lint-shell.sh` missing it also exits **2**. It never waves a push
+  through on the assumption that CI will catch it.
+- **The hook is actually in the scan set.** `lint-shell.sh` reports `Checking 14
+  shell file(s)` with `hooks/pre-push` present and **13** with it moved aside — so
+  the extensionless file is discovered by the shebang half of the linter's
+  two-signal union, rather than being silently skipped. This check exists because
+  the first attempt at it was ambiguous: a planted `[ $UNSET_VAR = "x" ]` was not
+  reported, which could equally have meant "file not scanned" or "defect below
+  `-S error`". It was the latter. A count that moves is unambiguous; a clean run
+  is not.
+- **It catches the real v1.8.14 defect.** Planting the exact failing shape — an
+  apostrophe inside a single-quoted string, `echo 'the fleet\'s thing'` — in
+  `hooks/pre-push` produces `SC1073`/`SC1072` at severity **error** and `rc=1`.
+  That is the defect that closed a string, truncated an `exec_test` body, sent its
+  tail to the runner's shell, and cost a 46-minute build.
+
+**The gate earned its keep inside the commit that added it.** The first version of
+the `smoke-test.sh` assertion above carried a comment beginning `# shellcheck is a
+GATE DEPENDENCY…`. A comment whose first word is the tool's name is parsed as a
+**shellcheck directive**, not a comment, so the new gate immediately failed with
+`SC1073`/`SC1072` at severity error — on the change that introduced it. Same family
+as the v1.8.14 apostrophe: a line that reads as prose to a human and as syntax to
+the parser. Before this change that defect would have been discovered in CI.
+
+**Also queued, not yet pinned:** the `mempalace-toolkit` owed-set derivation now
+honours a requester withdrawing its *own* ask (`isWithdrawn`, RFC 003 §3.3
+clause 4, with `scripts/test-owed-withdrawal.sh`) — toolkit commit **`e2b060a`**,
+which is the minimum revision for the behaviour. This image still pins `e45f6b4`.
+Until an image bakes `e2b060a` or later, a sender must assume its withdrawal has
+no effect on the recipient's mailbox — measured cost of the gap: a withdrawn
+v1.8.13 rollout ask was still being reported as owed on `tor-ms22` 41 hours later,
+for a release that device never installed. The same commit also anchors the
+derivation's `mine` query at the newest end (`order: "desc"`); with the previous
+default `asc` + `limit: 100`, a device passing 100 authored events would have its
+recent replies fall out of the join window and see answered asks resurface.
+
+---
+
+## v1.8.14 — 2026-09-08
+
+> **First release attempt failed; fixed in this same entry.** The `smoke` and
+> `smoke-studio` jobs both failed at `scripts/smoke-test.sh:770` with
+> `agent-browser: command not found`, after `build-base` had already succeeded
+> (~46 min spent). Root cause was in the agent-browser execution guard added the
+> day before: the explanatory comment inside the **single-quoted** `exec_test`
+> body contained an apostrophe (`the fleet\'s`). Inside `'...'` bash treats a
+> backslash literally, so `\'` does not escape — it **closes the string**. The
+> body silently truncated (measured: `exec_test` received **12** arguments
+> instead of 2), and the remaining lines, including the `agent-browser --version`
+> assertion, were parsed by the **runner's** shell instead of executing inside
+> the image — and the runner has no agent-browser. The prose now lives above the
+> call, where an apostrophe is harmless.
+>
+> **The lint job had already caught this, and it went unread for 24 hours.**
+> `shellcheck` flagged it as `SC2289` at severity *error*, so the `actionlint`
+> job went red at run 186 on 2026-09-07 21:21 — the exact push that introduced
+> the guard — and stayed red for runs 187 and 188. `lint.yml` deliberately
+> excludes tag pushes (documented: the tagged tree was already linted on main,
+> and a tag-ref lint run would sort above the publish run), which is sound; the
+> broken assumption was different, namely that a tree whose lint FAILED would not
+> then be released. `docker-publish.yml` has no dependency on lint, so it built
+> for 50 minutes on a tree known to be defective.
+>
+> **Fixed, then gated.** The prose moved above the `exec_test` call so an
+> apostrophe cannot terminate anything, and the shell-lint logic moved out of
+> `lint.yml` into **`scripts/lint-shell.sh`** — now called by both `lint.yml` and
+> a new `lint-gate` job here that `resolve-versions` depends on. A release with a
+> lint error refuses in ~40 s instead of failing after fifty minutes. One copy,
+> not two: a duplicated check that drifts is the failure this repo keeps paying
+> for. The script also refuses to pass when `shellcheck` is absent, inheriting
+> the existing principle that a gate which cannot run must not pass.
+>
+> **`v1.8.14` was re-pointed** from `601fc98` to the fix commit. Nothing had
+> consumed the original tag — no `v1.8.14` image was ever published, only the
+> content-addressed `base-a365dd24de21`. `scripts/` does not feed the base hash,
+> so the re-run reuses that base and skips the 46-minute rebuild.
+
+**A test that was quietly checking nothing, and a version number that was wrong.**
+Both found by delegating a read-only audit of this repo to a headless worker
+(`pi-toolkit` `bin/pi-task`) and then spot-checking its pointers from the
+filesystem — 5 of 5 held, and it also corrected a false premise planted in its
+own brief.
+
+**The node major is now asserted, not merely printed.**
+`scripts/smoke-test.sh` ran `run "node" "node --version"`, which asserts only
+that the binary exists and exits 0 — the printed version was compared to
+nothing. The line above it has always used `run_expect` against
+`$EXPECTED_PI_VERSION` for `pi`, so the suite *looked* like it covered node.
+**A node major bump would have passed the whole smoke suite silently.** Worse,
+this is where the "node v22.23.2 verified" line in the v1.8.13 recreate notes
+came from: printed output, not an assertion — an expectation stated up front and
+then falsified by the check.
+
+Now gated on `EXPECTED_NODE_MAJOR`, which CI derives from `Dockerfile.base`'s
+`ARG NODE_VERSION` — the single source of truth, and the *only* hard node pin in
+the repo (`Dockerfile.variant` has no node install at all, so the two Dockerfiles
+cannot disagree). That also catches a stale cached layer whose node disagrees
+with the declared ARG. Unset ⇒ previous behaviour, so nothing breaks for anyone
+running the suite by hand.
+
+Verified two-sided, because a silent failure here reintroduces the exact bug it
+fixes: the `sed` derivation yields `22` (an empty result would disable the
+assertion silently); `grep -Fq "v22."` matches `v22.23.2`; `"v24."` does **not**
+match, so a wrong major is caught; `"v2."` does not prefix-collide. The workflow
+YAML was re-parsed after editing (9 jobs).
+
+**v1.8.13's agent-browser version was wrong.** That entry said "the image's own
+0.35.2". The image ships **0.36.0** — `/usr/lib/node_modules/agent-browser` at
+0.36.0 with `engines.node >=24.0.0`, and no 0.35.2 exists anywhere in the image.
+The sentence was also internally incoherent, contrasting 0.36.0 against a version
+that is not present. Corrected in place with a visible note, since that entry is
+already released. **The reasoning survives untouched**: the engines floor really
+is vestigial, because `/usr/bin/agent-browser` is a prebuilt aarch64 ELF invoked
+directly and never through node — which is exactly why 0.36.0 runs fine on
+22.23.2, consistent with the runtime proof collected on 2026-09-07 and with the
+retraction of the earlier false "0.36.0 requires node >= 24" alert.
+
+No image content changes: `NODE_VERSION` still 22, no pins moved. This is a test
+and a docs correction only.
+
+**The same bug class, twice in one file — and the second one was throwing away a
+proof the fleet cannot obtain any other way.** `scripts/smoke-test.sh`'s
+agent-browser guard captured the version *inside an `echo`, with `2>/dev/null`*:
+
+```sh
+echo "resolved=[$r] version=[$(agent-browser --version 2>/dev/null | head -n1)]" >&2
+```
+
+The exit code was discarded, so a binary that could not execute at all still
+**passed**, printing `version=[]`. Verified two-sided: a stub exiting 127 passes
+the old form and is caught by the new one.
+
+Why that exit code matters more than most: smoke runs `platforms: linux/amd64` on
+an x86 runner, i.e. **native amd64**, making this line the fleet's only recurring
+amd64 runtime proof for agent-browser's `linux-x64` ELF. **No devbox can ever
+supply one** — every machine in the pi fleet is an Apple Silicon Mac
+(`mbp-m1-2020`; `tor-ms22` = Mac Studio `Mac13,1` M1 Max, verified 2026-08-17 by
+`system_profiler`; `emb-7kj4vr4g` = Apple Silicon, verified 4 ways 2026-09-07).
+The "amd64 runtime proof still needed" item that was sent to two devices was
+therefore asking for the impossible, while CI already had the answer and was
+discarding it. `Dockerfile.base:607` does assert it (`agent-browser --version &&`),
+but only when the base actually rebuilds — and v1.8.13's base was cached.
+
+**The mailbox now announces replies that CLOSE your own asks.** `mempalace-toolkit`
+`21023e7` → `e45f6b4`, which adds `deriveClosed()` alongside `deriveOwed()`. The old
+path queried `status: open` and joined for a reply, which by construction can only
+surface asks *you owe someone else*; a terminal reply carries `status: applied`
+(or `blocked`/`failed`), so **the answer to your own question was structurally
+invisible** — the one notification a human actually wants. Measured: `emb-7kj4vr4g`
+closed the v1.8.13 rollout ask at 18:31Z with `status=applied`, the operator
+reasonably expected to hear about it, and the mailbox stayed silent while being
+correct by its own definition. Nine closed correlations were sitting unannounced.
+Shares the 1-hour resurface floor, so a close is announced once and is news rather
+than a nag.
+
+This lands **because the base rebuilds**, which is worth stating explicitly: the
+CI-resolved `mempalace-toolkit` SHA is folded into the content-addressed base tag
+(`base-decide`), precisely so a toolkit-only fix cannot silently fail to land
+behind an unchanged `Dockerfile.base`. The floating `main` ref was left alone on
+purpose — the toolkit moving *forces* the rebuild rather than waiting for one.
+
+**A consequence worth noting for the amd64 item above: this release actually
+collects that proof.** v1.8.13's base was cached, which is why
+`Dockerfile.base:607`'s `agent-browser --version &&` never ran. v1.8.14's base is
+not cached, so both that assertion and the new `EXPECTED_NODE_MAJOR` gate execute
+on a native `linux/amd64` runner. The fleet's first *kept* amd64 runtime proof for
+the `linux-x64` ELF should be an artefact of this build rather than something
+asked of a device that cannot supply it.
+
+**Subtask delegation is documented — including the rung nobody built.** The image
+picks these up through their resolved refs (`pi-toolkit` `adfb553`,
+`pi-extensions` `c64c122`, the latter also refreshing the baked fallback skill):
+
+- an operator-facing decision guide in pi-toolkit's `README.md`, built on the
+  L0–L4 context ladder — how much of the parent session a child can see is the
+  axis that explains nearly every observed good and bad behaviour;
+- the canonical `pi-extensions` skill gains the same ladder next to *Boundary
+  discipline*, which until now diagnosed why an inherited transcript defeats a
+  brief without offering any alternative to "don't fork that";
+- one bullet in the global `AGENTS.md`, so the choice is visible without loading
+  a skill, and naming `pi-task` as a **CLI** — an agent hunting for a `pi_task`
+  tool finds none and concludes it is unavailable.
+
+What the ladder records: **L0/L1/L2 exist** in `pi-task` (`context.facts` /
+`.files` / `.commands`), **L4** is `fork`'s only behaviour (`getHeader()` +
+`getBranch()`, no offset or limit anywhere in the call chain), and **L3** — a
+truncated branch — **is not implemented by anything**, which is now written down
+instead of being a design idea somebody remembers.
+
+Also recorded, found while writing the above: `pi-fork/src/runner.ts:188` reads
+`if (extensions !== null) args.push("--no-extensions")`. So `extensions: []` turns
+the capability floor **on** and `null` turns it **off** — and `null` is the
+documented way to "restore normal extension loading", so tidying `[]` to `null`
+as a no-op re-arms palace writes inside every fork child. `pi-task` hardcodes the
+flag and cannot drift this way. Documented in three places because the edit that
+triggers it looks harmless.
+
+---
+
 ## v1.8.13 — 2026-09-06
 
 **Version audit + three pins moved, one deliberately not moved.** `pi`
@@ -56,9 +300,15 @@ identically to the 0.84.4 control, so "alive" could be distinguished from
 safe: all five prebuilt native addons in pi use NAPI (ABI-stable, no
 NODE_MODULE_VERSION lock, no binding.gyp), nothing in the image declares a node
 CEILING, and the install is one token (`setup_${NODE_VERSION}.x`). agent-browser
-0.36.0 declares `engines.node >=24`, but that field is vestigial for the
+0.36.0 declares `engines.node >=24.0.0`, but that field is vestigial for the
-artifact actually shipped: the image's own 0.35.2 declares the same floor and
+artifact actually shipped: `/usr/bin/agent-browser` is the prebuilt aarch64 ELF
-runs fine on 22.23.2 as a prebuilt aarch64 ELF. The reason to wait is
+`bin/agent-browser-linux-arm64`, invoked directly and never through node, so npm's
+engines floor is never enforced at runtime — verified running under 22.23.2 in
+this image. (Corrected 2026-09-07: this paragraph originally said "the image's own
+0.35.2 declares the same floor". That was wrong and incoherent — it contrasted
+0.36.0 against a 0.35.2 that does not exist in the image. There is exactly one
+agent-browser present, `/usr/lib/node_modules/agent-browser` at 0.36.0. The
+argument is unaffected; only the version was wrong.) The reason to wait is
 attribution, not compatibility — this release already moves pi a minor,
 mempalace a minor and bakes a Studio RC, so adding a node major would leave four
 suspects if the image misbehaves. Worth doing as its own release with the smoke

Dockerfile.base

@@ -101,6 +101,27 @@ ENV DEBIAN_FRONTEND=noninteractive
 #                  container: `ss` lands at /usr/bin/ss, `ip` at /usr/sbin/ip
 #                  (both already on the developer PATH), and `portcheck --all`
 #                  then correctly identifies the socat listener on 8765.
+#   shellcheck   — shell linter. Added 2026-09-09 to close a CAPABILITY gap, not
+#                  a style preference. `scripts/lint-shell.sh` is the release
+#                  GATE (the `lint-gate` job that `resolve-versions` depends
+#                  on), and it correctly refuses to pass when shellcheck is
+#                  missing — "a gate that cannot run must not pass". Measured on
+#                  v1.8.14: shellcheck was absent from this image by all three
+#                  routes (PATH, dpkg, filesystem), so `bash
+#                  scripts/lint-shell.sh` exited 2 in EVERY devbox container and
+#                  no developer could run the release gate locally at all. The
+#                  loop was therefore write-shell → push → wait for CI → discover,
+#                  which is the loop the gate was added to shorten: v1.8.14's
+#                  first attempt burned ~46 min on a tree whose lint had already
+#                  been red for 24 h. This is also what makes a client-side
+#                  pre-push hook possible (see hooks/pre-push); without the
+#                  binary that hook would refuse every push. ~39 MB installed
+#                  (Installed-Size 40112 KB, shellcheck 0.10.0-1) and measured
+#                  to pull ZERO additional packages under
+#                  --no-install-recommends: its deps (libc6, libffi8, libgmp10)
+#                  are already present. NOTE this file feeds the base-decide
+#                  hash (Dockerfile.base + rootfs/), so adding it forces one
+#                  full base rebuild.
 RUN apt-get update && \
     apt-get upgrade -y --no-install-recommends && \
     apt-get install -y --no-install-recommends \
@@ -120,6 +141,7 @@ RUN apt-get update && \
     make \
     patch \
     diffutils \
+    shellcheck \
     git-crypt \
     age \
     file \

hooks/pre-push

@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+# Pre-push gate for pi-devbox: shellcheck every shell script before it leaves
+# this clone. Thin wrapper — all logic lives in scripts/lint-shell.sh, which is
+# the SAME script the CI release gate runs. One copy, not two: a duplicated
+# check that drifts is the failure this repo keeps paying for.
+#
+# Install per clone:  git config core.hooksPath hooks
+# Bypass this gate:   git push --no-verify   (a guard, not a wall)
+#
+# WHY THIS HOOK EXISTS
+#   v1.8.14's first release attempt died at scripts/smoke-test.sh:770 after
+#   build-base had already spent ~46 minutes. shellcheck had ALREADY caught the
+#   defect — SC2289 at severity error, on the very push that introduced it — and
+#   the lint job stayed red for 24 hours, unread, across three runs. The fix at
+#   the time was to gate the release on the same script (the `lint-gate` job).
+#   This hook is the cheaper end of that: the same finding, before the push,
+#   in seconds rather than after a 40 s CI gate or a 46 min build.
+#
+# WHY IT COULD NOT EXIST UNTIL NOW
+#   Measured on v1.8.14 (2026-09-09): shellcheck was absent from the devbox
+#   image by all three routes — PATH, dpkg and a filesystem search. So
+#   lint-shell.sh exited 2 in every container, and a hook calling it would have
+#   refused EVERY push rather than gating anything. `shellcheck` was added to
+#   Dockerfile.base in the same change that added this file; on an image built
+#   before that, enable this hook and you will simply be told the gate cannot
+#   run. That is the correct behaviour, but it is not a working hook — so do not
+#   set core.hooksPath on a container older than the release that bakes it.
+#
+# NOTE ON SCOPE: this lints the WORKING TREE, not the exact commit range being
+# pushed. That is deliberate and matches what the CI gate does to the tagged
+# tree. It means a defect you have staged-but-not-committed is also reported,
+# which is noisy in the safe direction.
+set -euo pipefail
+
+HOOK_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "$HOOK_DIR/.." && pwd)"
+LINTER="$REPO_ROOT/scripts/lint-shell.sh"
+tag="[lint-shell]"
+
+# Same rule the gate itself applies, applied one level up: a missing check is
+# not a pass. If the script is gone, the push is refused rather than waved
+# through on the assumption that CI will catch it.
+if [ ! -r "$LINTER" ]; then
+    echo "$tag refusing the push: $LINTER is missing, so the gate cannot" >&2
+    echo "$tag run. A gate that cannot run must not pass." >&2
+    exit 2
+fi
+
+# Point the message at the actual remedy when the binary is absent, because the
+# linter's own message ("install it or run this in CI") is written for a CI
+# runner and is misleading inside a container the developer cannot apt-install
+# into persistently.
+if ! command -v shellcheck >/dev/null 2>&1; then
+    echo "$tag refusing the push: shellcheck is not installed, so the gate" >&2
+    echo "$tag cannot run. A gate that cannot run must not pass." >&2
+    echo "$tag" >&2
+    echo "$tag This container predates the image that bakes shellcheck." >&2
+    echo "$tag Either recreate onto an image that has it, or unset the hook:" >&2
+    echo "$tag   git config --unset core.hooksPath" >&2
+    echo "$tag To push this once without the gate: git push --no-verify" >&2
+    exit 2
+fi
+
+exec bash "$LINTER" "$REPO_ROOT"

scripts/lint-shell.sh

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+# Shellcheck + syntax-check every shell script in this repo. Severity: error.
+#
+# SINGLE SOURCE OF TRUTH for two callers:
+#   .gitea/workflows/lint.yml         — advisory, every branch push and PR
+#   .gitea/workflows/docker-publish.yml — the release GATE (lint-gate job)
+# Extracted from lint.yml on 2026-09-08 rather than copied, because a second
+# copy is exactly the drift this repo has been bitten by (see skillset's
+# pi-extensions mirror, refreshed the same evening after sitting 9579 B behind).
+#
+# WHY THIS CHECK EXISTS AT ALL
+#   actionlint shellchecks workflow `run:` steps only. The repo's own scripts —
+#   entrypoint.sh, scripts/*.sh, and the extensionless tools under
+#   rootfs/usr/local/bin/ — were never shellchecked. A sibling repo with the same
+#   gap shipped a broken `echo "$json" | python3 <<'EOF' ... json.load(sys.stdin)`
+#   for two months: with no script argument python reads its SCRIPT from stdin,
+#   so the heredoc IS stdin and json.load hits EOF. shellcheck flags that at
+#   severity error (SC2259); nothing ever ran it.
+#
+# WHY THE RELEASE GATES ON IT (added 2026-09-08, the expensive way round)
+#   v1.8.14's first attempt failed after build-base had already spent ~46 min:
+#   scripts/smoke-test.sh had an apostrophe inside a single-quoted exec_test body
+#   ("the fleet\'s"), which CLOSES the string, so the body truncated and its tail
+#   ran on the CI runner instead of inside the image. shellcheck had already
+#   caught it as SC2289 at severity error — the lint job went red on the very
+#   push that introduced it and stayed red for 24 hours, unread. lint.yml
+#   deliberately does not run on tag pushes (sound: the tagged tree was linted on
+#   main, and a tag-ref lint run sorts above the publish run and makes a release
+#   look finished early). The gap was never "lint the tag" — it was that a tree
+#   whose lint FAILED could still be released. Hence a gate inside the publish
+#   workflow, ~40 s, ahead of everything expensive.
+#
+# SEVERITY CHOICE
+#   -S error is 0 findings across this repo when clean, so it is free to add.
+#   -S warning is NOT free here (19x SC2088 tilde-in-quotes in
+#   recreate-sanity-check.sh, plus assorted SC2016 — both intentional), and a
+#   noisy gate trains people to ignore it. Error-only, matching the
+#   SHELLCHECK_OPTS philosophy in lint.yml.
+#
+# Usage:  bash scripts/lint-shell.sh [root]     (default root: repo top level)
+set -uo pipefail
+
+root="${1:-}"
+if [ -z "$root" ]; then
+    root="$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
+fi
+cd "$root" || { echo "::error::cannot cd to $root"; exit 2; }
+
+# A gate that cannot run must not pass. Without this, a machine (or a CI job
+# whose install step was reordered away) without shellcheck would sail through
+# printing nothing, which is the failure mode this whole file exists to prevent.
+if ! command -v shellcheck >/dev/null 2>&1; then
+    echo "::error::shellcheck not found — the gate cannot run, so it must not pass" >&2
+    echo "         install it (apt-get install -y shellcheck) or run this in CI" >&2
+    exit 2
+fi
+
+# Union of two signals, because either alone misses a real case: a shebang scan
+# misses a sourced fragment with no shebang, and a *.sh glob misses the
+# extensionless tools in rootfs/usr/local/bin/. Silent skipping is precisely the
+# failure mode this gate exists to prevent, so err toward over-collecting.
+# -print0/mapfile -d '' so a path containing a space cannot silently split.
+mapfile -d '' -t all_files < <(find . -not -path './.git/*' -type f -print0)
+sh_files=()
+for f in "${all_files[@]}"; do
+    case "$f" in *.sh) sh_files+=("$f"); continue;; esac
+    if head -n1 "$f" 2>/dev/null | grep -qE '^#!.*\b(bash|sh)\b'; then
+        sh_files+=("$f")
+    fi
+done
+
+echo "Checking ${#sh_files[@]} shell file(s) with $(shellcheck --version | awk '/version:/{print $2}')"
+# A green tick over an empty file set is not a check.
+if [ "${#sh_files[@]}" -eq 0 ]; then
+    echo "::error::no shell files found — the shebang scan or the checkout is wrong"
+    exit 1
+fi
+
+rc=0
+shellcheck -S error -f gcc "${sh_files[@]}" || rc=1
+
+# bash -n catches a different class than shellcheck (unbalanced constructs it
+# declines to parse), so both run and both count.
+for f in "${sh_files[@]}"; do
+    bash -n "$f" || { echo "::error file=$f::bash -n failed"; rc=1; }
+done
+
+if [ "$rc" -eq 0 ]; then
+    echo "OK: ${#sh_files[@]} shell file(s) clean at severity error"
+fi
+exit "$rc"

scripts/smoke-test.sh

@@ -5,6 +5,7 @@
 #
 # Verifies:
 #   - pi binary present and (if EXPECTED_PI_VERSION set) matches CI's resolved version
+#   - node MAJOR matches Dockerfile.base's ARG NODE_VERSION (if EXPECTED_NODE_MAJOR set)
 #   - mempalace core matches the audited pin (if EXPECTED_MEMPALACE_VERSION set)
 #   - new v1.0.0 base additions (pandoc, graphviz, imagemagick, yq, tealdeer)
 #   - typst PDF engine for pandoc (v1.4.0) — `pandoc --pdf-engine=typst`
@@ -91,8 +92,31 @@ if [ -n "${EXPECTED_PI_VERSION:-}" ]; then
 else
   run "pi"              "pi --version"
 fi
-run "node"            "node --version"
+# Until 2026-09-07 this was a bare `run "node" "node --version"`, which asserts
+# only that the binary exists and exits 0 — the printed version was never
+# compared to anything. A node major bump would therefore have passed this suite
+# SILENTLY, while a reader skimming it would reasonably assume node regressions
+# were covered. EXPECTED_NODE_MAJOR closes that: CI derives it from
+# Dockerfile.base's ARG NODE_VERSION (the single source of truth), so this also
+# catches a stale cached layer whose node does not match the declared ARG.
+if [ -n "${EXPECTED_NODE_MAJOR:-}" ]; then
+  run_expect "node major matches Dockerfile ARG" "node --version" "v${EXPECTED_NODE_MAJOR}."
+else
+  run "node"            "node --version"
+fi
 run "git"             "git --version"
+# NOTE: the shellcheck binary is a GATE DEPENDENCY, not a convenience.
+# scripts/lint-shell.sh is the release gate (the lint-gate job resolve-versions
+# depends on) and it exits 2 when the binary is missing, by design — "a gate that
+# cannot run must not pass". Measured on v1.8.14: it was absent from the image, so
+# that gate could not be run by a developer in ANY container, only in CI.
+# Asserted here so its absence fails a build instead of being discovered by a hook
+# that then refuses every push (hooks/pre-push).
+#
+# This comment must not BEGIN with the tool's name: a line starting with
+# `# shellcheck` is parsed as a DIRECTIVE, not a comment (SC1073/SC1072). The
+# gate added in this same change caught that here, before the push.
+run "shellcheck (lint gate dependency)" "shellcheck --version | grep -qE '^version: [0-9]'"
 run "aws"             "aws --version"
 run "uv"              "uv --version"
 run "nvim"            "nvim --version"
@@ -739,10 +763,33 @@ exec_test "pi-atelier registered from /opt, not npm: (volume-shadowing guard)" \
 # shadows it. The check that actually bites lives in
 # recreate-sanity-check.sh, which runs where the volume is real — that is
 # where a 7-week-old 0.27.0 was caught shadowing 0.35.2 on 2026-09-06.
+# EXECUTION is ASSERTED here, not printed. Until 2026-09-07 the version was
+# captured inside an echo with 2>/dev/null, so a binary that could not run at all
+# still PASSED and simply printed version=[] -- the same failure class as the bare
+# `node --version` two hundred lines up: a value displayed rather than compared.
+#
+# Why this exit code matters more than most: smoke runs `platforms: linux/amd64`
+# on an x86 runner, i.e. NATIVE amd64, so this is the fleet's only recurring
+# amd64 runtime proof for the linux-x64 ELF. No devbox can supply one -- every
+# machine in the pi fleet is an Apple Silicon Mac (mbp-m1-2020; tor-ms22 = Mac
+# Studio Mac13,1 M1 Max, verified 2026-08-17 by system_profiler; emb-7kj4vr4g =
+# Apple Silicon, 4 routes 2026-09-07). Asking a device for that proof is asking
+# for the impossible; CI already had it and was discarding it.
+#
+# KEEP PROSE OUT OF THE QUOTED BODY BELOW. On 2026-09-07 this explanation lived
+# INSIDE the single-quoted argument and contained an apostrophe ("the fleet's").
+# Inside '...' bash treats a backslash literally, so \' does not escape -- it
+# CLOSES the string. The body silently truncated, the remaining lines were parsed
+# by the RUNNER's shell instead of the container's, and `agent-browser --version`
+# ran on a host that has no agent-browser: "line 770: command not found", release
+# v1.8.14's smoke job failed after the base had already built. shellcheck caught
+# it as SC2289 the same day and the red lint job went unread for 24h.
 exec_test "agent-browser resolves under /usr (volume-shadowing guard, build-time half)" '
   p=$(command -v agent-browser) || { echo "agent-browser not on PATH" >&2; exit 1; }
   r=$(readlink -f "$p")
-  echo "resolved=[$r] version=[$(agent-browser --version 2>/dev/null | head -n1)]" >&2
+  v=$(agent-browser --version) || { echo "agent-browser did not EXECUTE" >&2; exit 1; }
+  test -n "$v" || { echo "agent-browser --version produced no output" >&2; exit 1; }
+  echo "resolved=[$r] version=[$(printf %s "$v" | head -n1)]" >&2
   case "$r" in /usr/*) ;; *) exit 1 ;; esac
   test ! -d "$HOME/.pi/npm-global/lib/node_modules/agent-browser" || exit 1
   echo ok