diff --git a/.dockerignore b/.dockerignore
index 8db1dad..9902b39 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,53 +1,86 @@
-# Mirrors .gitignore, with one deliberate exception: .gitignore itself stays
-# in the build context, because prettier 3 reads it as a default ignore file
-# and dropping it would change what the lint phase's prettier check sees.
+# .dockerignore does NOT use .gitignore semantics. Docker matches with
+# moby/patternmatcher: filepath.Match plus `**`, so `*` does not cross
+# `/` and an unprefixed pattern is anchored at the context root. Every
+# depth-independent pattern therefore needs `**/`, or `config/.env` and
+# `certs/server.key` still ship while this file reads as solved. Only
+# genuinely root-anchored entries go unprefixed. Never transplant these
+# into .gitignore, where `**/` is wrong.
 #
-# .git is deliberately NOT excluded: the build derives the version it stamps
-# from it (script/version). It is sent without its config, which holds the
-# clone's remote URL and any credential in it, and which the build stage, the
-# final image, would otherwise carry. git describe does not need it.
-.git/config
+# Matching is case-sensitive, so secrets use character ranges rather
+# than an ALL-CAPS twin, which would still miss `Server.Key`.
+#
+# Extend with this repo's own host-built artifacts, written anchored:
+# `/myapp`, never `**/myapp`, which also matches `cmd/myapp/` and
+# deletes the package directory from the context.
 
-# OS
-.DS_Store
-Thumbs.db
+# .git is sent without its config. Without a VERSION build argument the
+# stage that compiles runs `git describe --tags --always` on .git, which
+# does not need .git/config; that file can hold a credential, such as a
+# password in a remote URL or the token the CI checkout step stores there.
+# Each submodule keeps a config with the same exposure in its git directory
+# under .git/modules/, nested again for a submodule's own submodules, or in
+# its own .git directory when it keeps one.
+# KNOWN GAP: a submodule whose name has a `config` segment (`config`,
+# `deploy/config`, `config/lib`) loses its whole git directory, because
+# `**/.git/modules/**/config` also matches that segment's directory
+# under .git/modules/. Go's version stamping then fails the build;
+# nothing leaks. Name such a submodule without that segment:
+# `git submodule add --name`.
+**/.git/config
+**/.git/modules/**/config
 
-# Editors
-*.swp
-*.swo
-*~
-*.bak
-.idea/
-.vscode/
-*.sublime-*
+# Agent scratch: one full checkout of the repo per in-flight agent.
+# Anchored because it occurs once where agents run at the repo root.
+# KNOWN GAP: a repo running agents in subdirectories still ships
+# `services/api/.claude/` and must add its own anchored entry.
+.claude
 
-# Node
-node_modules
+# Environment files. `*.env` covers bare `.env` and the `prod.env`
+# convention. Re-include a committed template with a negation if the
+# build needs one: `!docs/example.env`.
+**/*.[eE][nN][vV]
+**/.[eE][nN][vV].*
+**/.[eE][nN][vV][rR][cC]
 
-# TypeScript / build artifacts
-dist
-build
-*.tsbuildinfo
-coverage
-.nyc_output/
+# Private keys and the bundles carrying them. Public certificates
+# (*.crt, *.cer) are deliberately absent: they are legitimate inputs.
+**/*.[pP][eE][mM]
+**/*.[kK][eE][yY]
+**/*.[pP]12
+**/*.[pP][fF][xX]
+**/[iI][dD]_[rR][sS][aA]
+**/[iI][dD]_[dD][sS][aA]
+**/[iI][dD]_[eE][cC][dD][sS][aA]
+**/[iI][dD]_[eE][cC][dD][sS][aA]_[sS][kK]
+**/[iI][dD]_[eE][dD]25519
+**/[iI][dD]_[eE][dD]25519_[sS][kK]
 
-# Vitest
-.vitest-cache/
+# Dependencies: restored inside the image, never copied in.
+**/node_modules
 
-# Environment / secrets
-.env
-.env.*
-*.pem
-*.key
+# OS metadata.
+**/.DS_Store
+**/Thumbs.db
+
+# Editor state: never a build input, and it churns COPY.
+**/*.swp
+**/*.swo
+**/*~
+**/*.bak
+**/.idea
+**/.vscode
+**/*.sublime-*
+
+# TypeScript / build artifacts: the image compiles its own.
+/dist
+/build
+/*.tsbuildinfo
+/coverage
+/.nyc_output
+/.vitest-cache
 
 # Compiled binary (built by make build-bin); around 100 MB
-bin/quak
+/bin/quak
 
 # quak runtime data (in case anyone runs the CLI from inside the repo)
-.quak/
-
-# Local per-developer tool state, including agent worktrees. Correctness,
-# not context size: a worktree copied in here has its own test/ tree, which
-# vitest globs alongside the real one, so the containerised suite runs N+1
-# times over and still reports success.
-.claude/
+/.quak
diff --git a/.gitignore b/.gitignore
index 7820f68..ca2f6e2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,9 +11,41 @@ Thumbs.db
 .vscode/
 *.sublime-*
 
+# Agent scratch (worktrees of this repo, created and destroyed by
+# in-flight tooling). Unanchored: .gitignore patterns already match at
+# every depth, so no prefix is wanted here. This is not a .dockerignore
+# entry and must not be given a `**/` prefix on the way into one.
+.claude/
+
 # Node
 node_modules/
 
+# Secrets. Unanchored like every entry above, so each matches at every
+# depth. Matching is case-sensitive on Linux, so names use character
+# ranges rather than a lowercase form that misses `Server.Key`.
+
+# Environment files. `*.env` covers bare `.env` and the `prod.env`
+# convention. Only the templates `example.env` and `sample.env` are
+# re-included below. A repository that commits any other template adds
+# its own negation after these lines, for example `!.env.example`.
+*.[eE][nN][vV]
+.[eE][nN][vV].*
+.[eE][nN][vV][rR][cC]
+!example.env
+!sample.env
+
+# Private keys and the bundles carrying them.
+*.[pP][eE][mM]
+*.[kK][eE][yY]
+*.[pP]12
+*.[pP][fF][xX]
+[iI][dD]_[rR][sS][aA]
+[iI][dD]_[dD][sS][aA]
+[iI][dD]_[eE][cC][dD][sS][aA]
+[iI][dD]_[eE][cC][dD][sS][aA]_[sS][kK]
+[iI][dD]_[eE][dD]25519
+[iI][dD]_[eE][dD]25519_[sS][kK]
+
 # TypeScript / build artifacts
 dist/
 build/
@@ -24,18 +56,8 @@ coverage/
 # Vitest
 .vitest-cache/
 
-# Environment / secrets
-.env
-.env.*
-*.pem
-*.key
-
 # Compiled binary (built by make build-bin)
 bin/quak
 
 # quak runtime data (in case anyone runs the CLI from inside the repo)
 .quak/
-
-# Local per-developer tool settings and scratch state, including the
-# worktrees agents check out under this directory
-.claude/
diff --git a/.prettierignore b/.prettierignore
index ffce635..23d67fc 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -1,5 +1,2 @@
 node_modules/
 yarn.lock
-dist/
-build/
-coverage/
diff --git a/Dockerfile b/Dockerfile
index 03a95a3..f67c63b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -58,6 +58,8 @@ COPY --from=test /app/package.json /dev/null
 COPY script/ script/
 COPY package.json yarn.lock ./
 RUN script/bootstrap
+# A tar-stream context keeps the sender's file owners, which git refuses.
+RUN git config --system --add safe.directory /app
 
 COPY . .
 
diff --git a/README.md b/README.md
index 354c53d..dbd05f2 100644
--- a/README.md
+++ b/README.md
@@ -137,16 +137,15 @@ alpine. We provide:
 - `script/lint` — run eslint and a prettier check, by building the `lint` phase
   of the `Dockerfile`; requires docker (see Linting and testing below)
 - `script/fmt` — format all files with prettier (writes)
-- `script/fmt-check` — check formatting on the host (read-only); standalone, and
-  not called by `script/check` or `script/precommit`, because `script/lint`
-  already checks formatting in the container
-- `script/check` — run all checks: `test`, `lint` (our own extension)
+- `script/fmt-check` — check formatting on the host (read-only)
+- `script/check` — run all checks: `test`, `lint`, `fmt-check` (our own
+  extension)
 - `script/docker` — build the image, tagged via `script/projectname`
-- `script/cibuild` — build the image (what CI runs); its last stage depends on
-  the `lint` and `test` phases, so this one build lints, tests and compiles
+- `script/cibuild` — what CI runs: `script/bootstrap`, then `script/check`, then
+  the image build
 - `script/precommit` — run by the git pre-commit hook (our own extension); runs
-  `script/lint`, which checks both lint and formatting, but deliberately not the
-  tests, so the TDD red-phase commit can land
+  `script/lint` and `script/fmt-check` but deliberately not the tests, so the
+  TDD red-phase commit can land
 - `script/install-precommit` — installs the git pre-commit hook (our own
   extension); `make hooks` shims to it
 
@@ -162,22 +161,19 @@ script runs the tools on the host: docker is required, and that also works where
 the docker daemon is remote and bind mounts are impossible.
 
 The last stage of the `Dockerfile` compiles the package, and it copies a file
-from each phase, so it cannot be built unless lint and the tests pass. That is
-why `script/cibuild` is a single `docker build`: it runs lint and the tests once
-each and then compiles.
+from each phase, so it cannot be built unless lint and the tests pass. The image
+build in `script/cibuild` therefore runs lint and the tests a second time, after
+`script/check` has run them.
 
 Every `docker build` in `script/` passes `--no-cache`. On an unchanged tree
 Docker would otherwise serve the lint and test steps from cache, nothing would
 run, and the build would still exit 0.
 
-The formatting check is part of the `lint` phase, not a step beside it, so
-`script/check` and `script/precommit` do not call `script/fmt-check` as well;
-that would run prettier a second time over the same tree for the same verdict.
-`script/fmt-check` remains as a standalone entrypoint for asking the formatting
-question on the host. Its verdict matches the container's: prettier is pinned to
-an exact version, installed from `yarn.lock` under `--frozen-lockfile` in both
-places, and reads `.gitignore` as its default ignore file — which is why
-`.dockerignore` keeps `.gitignore` in the build context.
+`script/fmt-check` runs prettier on the host. Its verdict matches the `lint`
+phase's: prettier is pinned to an exact version, installed from `yarn.lock`
+under `--frozen-lockfile` in both places, and reads `.gitignore` as its default
+ignore file — which is why `.dockerignore` keeps `.gitignore` in the build
+context.
 
 ### Version
 
@@ -259,11 +255,10 @@ All work on quak is test-driven. No exceptions.
    history must still show tests landing before (or with) the matching
    implementation.
 8. The pre-commit hook installed by `make hooks` runs `script/precommit`, which
-   runs `script/lint` — eslint and the prettier check, in the container — but
-   not the tests, and so not the full `make check`. This is deliberate so the
-   TDD red-phase commit (failing tests, no implementation yet) can land. The
-   `test` phase is part of the image build, which is what CI executes via
-   `script/cibuild`, so a red branch still cannot reach `next`.
+   runs `script/lint` and `script/fmt-check` but not the tests, and so not the
+   full `make check`. This is deliberate so the TDD red-phase commit (failing
+   tests, no implementation yet) can land. CI executes `script/cibuild`, which
+   runs the tests, so a red branch still cannot reach `next`.
 
 ## Design
 
@@ -995,14 +990,12 @@ documents:
   before the implementation. Tests are the canonical API documentation and must
   be commented thoroughly. `main` and `next` are always green.
 
-- **Required checks before every commit:** `make lint` must pass — that is
-  eslint plus the prettier check, and it builds the `lint` phase of the
-  `Dockerfile`, so it needs docker. The pre-commit hook enforces exactly that.
-  `make check` (which also runs the tests) must pass before merging into `next`.
-  `make fmt-check` is available for a host-side formatting check on its own, but
-  it is not a separate requirement: `make lint` already covers it, and running
-  both would check formatting twice. Never invoke eslint or prettier directly;
-  linting runs in the container only.
+- **Required checks before every commit:** `make lint` and `make fmt-check` must
+  pass. `make lint` is eslint plus the prettier check, and it builds the `lint`
+  phase of the `Dockerfile`, so it needs docker. The pre-commit hook enforces
+  exactly that. `make check` (which also runs the tests) must pass before
+  merging into `next`. Never invoke eslint or prettier directly; linting runs in
+  the container only.
 
 - **Formatting:** prettier with 4-space indents and `proseWrap: always` for
   markdown. Use `make fmt` to format. Use `yarn` not `npm`.
diff --git a/REPO_POLICIES.md b/REPO_POLICIES.md
index 2256291..20382d1 100644
--- a/REPO_POLICIES.md
+++ b/REPO_POLICIES.md
@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-09-08
+last_modified: 2026-10-04
 ---
 
 This document covers repository structure, tooling, and workflow standards. Code
@@ -104,10 +104,14 @@ style conventions are in separate documents:
   `lint` phase and a `test` phase, with the final stage depending on both so the
   image cannot be built unless they pass. For non-server repos the final stage
   brings up a development environment; for server repos it is the runtime image.
-  Dockerfiles install development prerequisites by running `script/bootstrap`
-  rather than duplicating installs inline; COPY `script/` and the dependency
-  manifests (`package.json` + `yarn.lock`, `go.mod` + `go.sum`, etc.) before
-  running it.
+  The gate phases and the build stage start from their pinned base images and
+  install what those images lack either inline, as the canonical Go `Dockerfile`
+  below does for `git`, or by running `script/bootstrap`, as the `prompts`
+  repo's own `Dockerfile` does for its yarn packages. The development
+  environment stage installs development prerequisites by running
+  `script/bootstrap` rather than duplicating its installs inline. A stage that
+  runs `script/bootstrap` COPYs `script/` and the dependency manifests
+  (`package.json` + `yarn.lock`, `go.mod` + `go.sum`, etc.) before running it.
 
 - **Linting and testing run in Docker, as phases of the `Dockerfile`.** There is
   no separate lint file. `script/lint` and `script/test` each build one phase
@@ -156,11 +160,14 @@ style conventions are in separate documents:
   not evidence that anything ran: a sub-second build reporting success is a
   cache hit, not a result. Never invalidate by pruning — `docker builder prune`
   and friends destroy a build cache shared with every other build on the host.
+  When a check is added or changed, prove it works by planting a defect it must
+  catch and watching the run fail on it, then revert the defect. A green run
+  alone shows neither that the check ran nor that it covers what it should.
 
 - **The gate phases are separate stages, and the build stage depends on both.**
   The lint phase is based on the `golangci/golangci-lint` image (pinned by
   hash), so lint failures surface in seconds rather than after a full compile,
-  and the test phase is based on the Go image. The canonical Go repo
+  and the test phase is based on the Debian Go image. The canonical Go repo
   `Dockerfile`:
 
     ```dockerfile
@@ -173,8 +180,9 @@ style conventions are in separate documents:
     COPY . .
     RUN golangci-lint run --config .golangci.yml ./...
 
-    # Test phase
-    # golang:1.x-alpine, YYYY-MM-DD
+    # Test phase. -race needs cgo and so a C compiler, which the Debian Go
+    # image ships and the alpine one does not.
+    # golang:1.x, YYYY-MM-DD
     FROM golang@sha256:... AS test
     WORKDIR /src
     COPY go.mod go.sum ./
@@ -191,15 +199,29 @@ style conventions are in separate documents:
     FROM golang@sha256:... AS builder
     COPY --from=lint /src/go.sum /dev/null
     COPY --from=test /src/go.sum /dev/null
+    RUN apk add --no-cache git
+    # A tar-stream context keeps the sender's file owners, which git refuses.
+    RUN git config --system --add safe.directory /src
     WORKDIR /src
     COPY go.mod go.sum ./
     RUN go mod download
     COPY . .
 
-    ARG VERSION=dev
-    RUN CGO_ENABLED=0 go build -trimpath \
-        -ldflags="-s -w -X main.Version=${VERSION}" \
-        -o /app ./cmd/app/
+    # The VERSION build arg when one is given, otherwise
+    # `git describe --tags --always` on the .git in the build context. With
+    # .git present, a version that is still empty, dev or unknown fails the
+    # build: git is missing or could not read the checkout.
+    ARG VERSION
+    RUN VERSION="${VERSION:-$(git describe --tags --always)}"; \
+        if [ -e .git ]; then \
+            case "$VERSION" in ""|dev|unknown) \
+                echo "version is '$VERSION' although .git is present" >&2; \
+                exit 1 ;; \
+            esac; \
+        fi; \
+        CGO_ENABLED=0 go build -trimpath \
+            -ldflags="-s -w -X main.Version=${VERSION}" \
+            -o /app ./cmd/app/
 
     # Runtime stage, and the last one
     FROM alpine@sha256:...
@@ -221,10 +243,41 @@ style conventions are in separate documents:
       (e.g. a web frontend compiled in a separate stage), the lint phase must
       create placeholder files so the embed directives resolve. Example:
       `RUN mkdir -p web/dist && touch web/dist/index.html web/dist/style.css`.
-    - If the project requires CGO or system libraries for linting (e.g.
-      `vips-dev`), install them in the lint phase with `apk add`.
-    - `ARG VERSION=dev` is declared in the stage that compiles and supplied by
-      `script/docker` and `script/cibuild`; no stage may call `git describe`.
+    - If the project requires CGO or system libraries for linting, install them
+      in the lint phase. The `golangci/golangci-lint` image is Debian-based and
+      has no `apk`, so install with `apt-get` under the Debian package name
+      (`libvips-dev`, where alpine says `vips-dev`), and delete the package
+      lists in the same `RUN`, so the layer does not keep them:
+
+        ```dockerfile
+        RUN apt-get update \
+            && apt-get install -y --no-install-recommends libvips-dev \
+            && rm -rf /var/lib/apt/lists/*
+        ```
+
+    - `.dockerignore` lets `.git` into the build context. It keeps out every git
+      `config` at any depth (`**/.git/config`, `**/.git/modules/**/config`): the
+      repository's own, each submodule's under `.git/modules/`, and that of a
+      submodule keeping its own `.git` directory. `git describe` does not need
+      them, and each can hold a credential: a password in a remote URL, or the
+      token the CI checkout step stores there. A submodule whose name has a
+      `config` segment (`config`, `deploy/config`, `config/lib`) loses its whole
+      git directory to `**/.git/modules/**/config`, and Go's version stamping
+      then fails the build: give it a name without that segment
+      (`git submodule add --name`). The stage that compiles has `git` (the
+      Debian Go image has it; an alpine one needs `apk add --no-cache git`) and
+      takes the version from the `VERSION` build argument when one is given,
+      otherwise from `git describe --tags --always`. That gives the tag on a
+      tagged commit; on a later commit, the tag, the number of commits since it
+      and the short commit (`v1.2.3-4-gabc1234`); and the short commit when no
+      tag is reachable. The stage that compiles also marks its working directory
+      safe for git (`git config --system --add safe.directory /src`): a context
+      sent as a tar stream keeps the sender's file owners, and git refuses a
+      checkout owned by another user, so the version would come out empty.
+      `ARG VERSION` has no default, and the build fails if the context carries
+      `.git` and the version still comes out empty, `dev` or `unknown`. A plain
+      `docker build .` with no build arguments must succeed; a Dockerfile that
+      refuses an empty build argument drops that refusal and keeps the argument.
 
 - Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
   runs `script/cibuild` on push, and checks out the repo as its only other step.
@@ -233,7 +286,12 @@ style conventions are in separate documents:
   carry the same guarantee, because its gate phases may come from the cache. The
   image build is uncached and so runs the gate phases a second time. That is the
   price of the rule above, and it is worth paying: the image that ships is built
-  from a run of its own gates rather than from a cache entry.
+  from a run of its own gates rather than from a cache entry. A separate
+  workflow limited to `main` by a `branches` list under `on: push` cannot be
+  checked by review: to try a change to it, add the feature branch to that list
+  and push, then remove the branch from the list again before merging. Keep any
+  job in it that publishes behind `if: github.ref_name == 'main'`, so the run
+  from the feature branch publishes nothing.
 
 - Use platform-standard formatters: `black` for Python, `prettier` for
   JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
@@ -286,17 +344,19 @@ style conventions are in separate documents:
     ```
 
     `-count=1` is required on both invocations: it defeats Go's test _result_
-    cache, so the target cannot report a pass it did not earn, and the rerun
-    reproduces a failure instead of replaying it. It leaves the build cache
-    alone, so it costs the runtime of the suite and no recompilation.
+    cache, so neither run can report a stored pass in place of running the
+    tests. It leaves the build cache alone, so it costs the runtime of the suite
+    and no recompilation.
 
-    Note that this is a second, independent cache, stacked below the Docker
-    layer cache that [issue #26](https://git.eeqj.de/sneak/prompts/issues/26)
-    addresses. `CHECK_EPOCH` guarantees the `RUN make test` _step_ re-executes;
-    it does not guarantee `go test` inside that step does any work, because the
-    `GOCACHE` baked into earlier image layers survives into the re-executed
-    step. They are two separate defects requiring two separate fixes, and a fix
-    for one must not be recorded as covering the other.
+    That cache is Go's own, separate from Docker's layer cache. Go stores a
+    passing result in its cache directory (`GOCACHE`), and when the same tests
+    run again on unchanged code it prints that result, marked `(cached)`,
+    without running them. That matters on a developer's machine, where this
+    target runs and the directory lasts from one run to the next. The `test`
+    phase of the `Dockerfile` needs no `-count=1`: its base image holds no
+    result for this repo's tests and nothing before its `go test` step runs a
+    test, so there is nothing to replay. `--no-cache` (above) is what makes that
+    step run on an unchanged tree.
 
     Python example:
 
@@ -340,7 +400,7 @@ style conventions are in separate documents:
   — which is more dangerous than a short file with no secret patterns at all,
   because it reads as solved and stops anyone looking. Give every
   depth-independent pattern the `**/` prefix and leave only genuinely
-  root-anchored entries unprefixed: `.git`, and the repo's own host-built
+  root-anchored entries unprefixed: `.claude`, and the repo's own host-built
   binary, written `/myapp` and never `**/myapp`, which would also match
   `cmd/myapp/` and delete the package directory from the context. Matching is
   case-sensitive, and an ALL-CAPS twin per pattern still misses `Server.Key`, so
@@ -365,12 +425,13 @@ style conventions are in separate documents:
   directory, so a repo running agents in subdirectories still ships
   `services/api/.claude/` and must add its own anchored entry there.
 
-- **Excluding `.git` means `git describe` cannot run inside any build stage, and
-  it fails quietly there.** In a build stage there is no repository, so
-  `git describe` writes nothing to stdout, `-X main.Version=` comes out empty,
-  the binary reports no version at all, and the build still exits 0. Compute the
-  version on the host and thread it in as a build arg. `script/docker` and
-  `script/cibuild` do this, byte-identically across repos:
+- **A plain `docker build .` of a clone stamps the version that
+  `git describe --tags --always` gives**, derived from the `.git` in the build
+  context as the canonical `Dockerfile` above shows. Without its failure check,
+  a missing `git` or an unreadable checkout would leave `-X main.Version=` empty
+  and the build would still exit 0. `script/docker` and `script/cibuild` pass
+  the version they compute on the host; it takes precedence. They do this
+  byte-identically across repos:
 
     ```sh
     # Own line: a failing command substitution inside an argument does not
@@ -387,7 +448,7 @@ style conventions are in separate documents:
     fallback is applied — a live check that fires on a build from an export with
     no `.git` and on a repository with no commits yet. Do not fold it into the
     substitution as `|| echo unknown`, which makes the guard unreachable. The
-    Dockerfile's side is `ARG VERSION=dev` in the stage that compiles, declared
+    Dockerfile's side is `ARG VERSION` in the stage that compiles, declared
     there because `ARG` is stage-scoped; passing `VERSION` to a repo whose
     Dockerfile declares no such `ARG` is ignored and costs nothing, which is why
     the scripts stay byte-identical. One consequence for CI: the standard
@@ -426,12 +487,18 @@ style conventions are in separate documents:
   `test-support` depguard rule, where a repo names its own test-support packages
   by full import path. A repo adds entries there and changes nothing else, and a
   re-vendor carries its entries forward. The canonical golangci-lint version is
-  v2.12.2 (released 2026-05-06), pinned as the digest of the lint phase's base
+  v2.14.0 (released 2026-09-24), pinned as the digest of the lint phase's base
   image
-  (`golangci/golangci-lint@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240`,
-  which reports `2.12.2 built with go1.26.2 from c0d3ddc9`). That digest is the
-  only pin, since no repo installs golangci-lint on the host: bumping the
-  version means changing it and nothing else.
+  (`golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a92406b2fd3898faf0bf98f`,
+  which reports `2.14.0 built with go1.27.0 from 114493f9`). A module's `go`
+  directive must not name a newer Go minor version than the one golangci-lint
+  was built with, or golangci-lint refuses to lint it: this release lints
+  `go 1.27.1` but not `go 1.28`. That digest is the only pin, since no repo
+  installs golangci-lint on the host. A repo sets the lint phase digest to the
+  one named here and re-vendors `.golangci.yml` in the same commit, whichever of
+  the two prompted the change: the canonical copy can name linters that an older
+  golangci-lint rejects, and a newer golangci-lint can add linters that
+  `default: all` switches on until the canonical copy disables them.
 
 - **`script/bootstrap` installs a pinned tool by comparing versions, never by
   testing presence.** An `if ! command -v <tool>; then install; fi` guard tests
@@ -455,6 +522,11 @@ style conventions are in separate documents:
 
     Keep it POSIX sh: no arrays, no `[[`, no `grep -P`.
 
+    A Go tool a repo needs on the host is installed with `go install` pinned to
+    a commit hash (`go install <package>@<commit hash>`). It is never tracked as
+    a `go.mod` tool dependency or through a `tools.go` file, either of which
+    pulls the tool's own dependencies into the repo's `go.mod` and `go.sum`.
+
 - When pinning images or packages by hash, add a comment above the reference
   with the version and date (YYYY-MM-DD).
 
@@ -567,10 +639,10 @@ style conventions are in separate documents:
   settings.
 
 - Avoid putting files in the repo root unless necessary. Root should contain
-  only project-level config files (`README.md`, `Makefile`, `Dockerfile`,
-  `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`, and
-  language-specific config). Everything else goes in a subdirectory. Canonical
-  subdirectory names:
+  only project-level config files (`README.md`, `AGENTS.md`, `Makefile`,
+  `Dockerfile`, `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`,
+  and language-specific config). Everything else goes in a subdirectory.
+  Canonical subdirectory names:
     - `bin/` — executable scripts and tools
     - `cmd/` — Go command entrypoints; thin only: one `main.go` per binary whose
       body is a single call into `internal/` or `pkg/`, no project logic in
@@ -601,3 +673,7 @@ style conventions are in separate documents:
     - Go: `go.mod`, `go.sum`, `.golangci.yml`
     - JS: `package.json`, `yarn.lock`, `.prettierrc`, `.prettierignore`
     - Python: `pyproject.toml`
+
+- Guidance for coding agents lives in one `AGENTS.md` at the repository root. It
+  is never committed under a file or directory named after one agent tool, such
+  as `CLAUDE.md` or `.claude/`, and never split into separate memory files.
diff --git a/TODO.md b/TODO.md
index c8baf5c..59e3228 100644
--- a/TODO.md
+++ b/TODO.md
@@ -25,6 +25,14 @@ declares one.
 
 # Completed Steps
 
+- 2026-10-06: The files this repository copies from `sneak/prompts` are copied
+  again from its commit `dd4027b` (issue 171). `.gitignore` and `.dockerignore`
+  keep out more secret files, and this repository's build artifacts follow the
+  copied content. `script/check` runs `script/fmt-check` again, `script/cibuild`
+  runs `script/bootstrap` and `script/check` before the image build,
+  `script/fmt` and `script/fmt-check` find the pinned yarn under nvm, and the
+  image's last stage marks `/app` safe for git.
+
 - 2026-10-06: `quak backup` writes the account and album records
   `backup-metadata` writes (issue 166): `account.json` with the account's
   `email` and `userID`, and in each album's JSON its `ownerID`, `isShared`,
diff --git a/script/check b/script/check
index 1607369..92875f7 100755
--- a/script/check
+++ b/script/check
@@ -1,11 +1,8 @@
 #!/bin/sh
-# script/check: run all checks (test, lint). Our own extension to
-# scripts-to-rule-them-all. Both are Docker phases. Must not modify any
-# files.
-#
-# script/fmt-check is not called here, unlike the template: the lint
-# phase already runs `prettier --check .`, so calling it would run
-# prettier a second time over the same tree for the same verdict.
+# script/check: run all checks (test, lint, fmt-check). Our own
+# extension to scripts-to-rule-them-all. test and lint are Docker
+# phases; fmt-check is native, because a formatter writes the working
+# tree. Must not modify any files.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -13,6 +10,7 @@ SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 main() {
     "$SCRIPT_DIR/test"
     "$SCRIPT_DIR/lint"
+    "$SCRIPT_DIR/fmt-check"
 }
 
 main "$@"
diff --git a/script/cibuild b/script/cibuild
index 38fecf3..d8d3200 100755
--- a/script/cibuild
+++ b/script/cibuild
@@ -1,8 +1,7 @@
 #!/bin/sh
-# script/cibuild: run the CI build. The image's last stage depends on the
-# lint and test phases, so this one build runs eslint, prettier and the
-# suite once each and then compiles. Unlike the template it does not run
-# script/check first, which would run lint and the tests a second time.
+# script/cibuild: run the CI build. It bootstraps first: a CI runner
+# checks out and runs this and nothing else, and script/fmt-check runs
+# the formatter on the host, which a pristine checkout cannot do.
 # --no-cache for the same reason as script/docker: the gate phases the
 # final stage depends on are RUN steps, and a cached one is a check that
 # did not run.
@@ -13,11 +12,12 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
+    "$SCRIPT_DIR/bootstrap"
+    "$SCRIPT_DIR/check"
     # Own line: a failing command substitution inside an argument does
     # not trip `set -e`, so the inline form degrades silently to an
-    # empty constant. The version resolved here goes in as the VERSION
-    # build arg, which takes precedence over what the build would derive
-    # from the .git in its context.
+    # empty constant. The VERSION build argument takes precedence over
+    # the version a build stage derives from the .git in the context.
     version="$(git describe --tags --always --dirty 2>/dev/null || true)"
     [ -n "$version" ] || version="unknown"
     docker build --no-cache \
diff --git a/script/docker b/script/docker
index 940f456..07b626c 100755
--- a/script/docker
+++ b/script/docker
@@ -12,9 +12,8 @@ main() {
     cd "$ROOT"
     # Own line: a failing command substitution inside an argument does
     # not trip `set -e`, so the inline form degrades silently to an
-    # empty constant. The version resolved here goes in as the VERSION
-    # build arg, which takes precedence over what the build would derive
-    # from the .git in its context.
+    # empty constant. The VERSION build argument takes precedence over
+    # the version a build stage derives from the .git in the context.
     version="$(git describe --tags --always --dirty 2>/dev/null || true)"
     [ -n "$version" ] || version="unknown"
     docker build --no-cache \
diff --git a/script/fmt b/script/fmt
index 52825df..fe1b79a 100755
--- a/script/fmt
+++ b/script/fmt
@@ -4,9 +4,28 @@ set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
+# Must match the pin in script/bootstrap.
+NODE_VERSION="22.17.0"
+
+# script/bootstrap installs node and yarn under nvm and leaves neither
+# on the PATH of the shell that called it, so resolve the pinned
+# toolchain here the way bootstrap's own install step does. nvm is a
+# bash script, hence the subshell.
+run_yarn() {
+    if command -v yarn >/dev/null 2>&1; then
+        exec yarn "$@"
+    fi
+    if [ ! -s "$HOME/.nvm/nvm.sh" ]; then
+        echo "fmt: no yarn; run script/bootstrap first" >&2
+        exit 1
+    fi
+    exec bash -c '. "$HOME/.nvm/nvm.sh" && nvm use "$1" >/dev/null &&
+        shift && exec yarn "$@"' bash "$NODE_VERSION" "$@"
+}
+
 main() {
     cd "$ROOT"
-    yarn run prettier --write .
+    run_yarn run prettier --write .
 }
 
 main "$@"
diff --git a/script/fmt-check b/script/fmt-check
index adfaff4..0e164bd 100755
--- a/script/fmt-check
+++ b/script/fmt-check
@@ -4,9 +4,28 @@ set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
+# Must match the pin in script/bootstrap.
+NODE_VERSION="22.17.0"
+
+# script/bootstrap installs node and yarn under nvm and leaves neither
+# on the PATH of the shell that called it, so resolve the pinned
+# toolchain here the way bootstrap's own install step does. nvm is a
+# bash script, hence the subshell.
+run_yarn() {
+    if command -v yarn >/dev/null 2>&1; then
+        exec yarn "$@"
+    fi
+    if [ ! -s "$HOME/.nvm/nvm.sh" ]; then
+        echo "fmt-check: no yarn; run script/bootstrap first" >&2
+        exit 1
+    fi
+    exec bash -c '. "$HOME/.nvm/nvm.sh" && nvm use "$1" >/dev/null &&
+        shift && exec yarn "$@"' bash "$NODE_VERSION" "$@"
+}
+
 main() {
     cd "$ROOT"
-    yarn run prettier --check .
+    run_yarn run prettier --check .
 }
 
 main "$@"
diff --git a/script/precommit b/script/precommit
index e87c5c8..af98730 100755
--- a/script/precommit
+++ b/script/precommit
@@ -2,17 +2,17 @@
 # script/precommit: run by the git pre-commit hook; fails the commit if
 # checks fail. Our own extension to scripts-to-rule-them-all.
 #
-# Runs lint but deliberately NOT the tests, so the TDD red-phase commit
-# (failing tests, no implementation yet) can land. CI runs
-# script/cibuild, whose image build includes the test phase, and so
-# catches any branch that ships red. The lint phase includes the
-# prettier check, so a badly formatted tree still fails the commit.
+# Runs lint and fmt-check but deliberately NOT the tests, so the TDD
+# red-phase commit (failing tests, no implementation yet) can land. CI
+# runs script/cibuild, which runs the tests, and so catches any branch
+# that ships red.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 
 main() {
     "$SCRIPT_DIR/lint"
+    "$SCRIPT_DIR/fmt-check"
 }
 
 main "$@"
diff --git a/test/packaging/build-context.test.ts b/test/packaging/build-context.test.ts
index ea52581..8d9c103 100644
--- a/test/packaging/build-context.test.ts
+++ b/test/packaging/build-context.test.ts
@@ -29,18 +29,19 @@ const patterns = (name: string): string[] =>
 const dockerignore = patterns(".dockerignore");
 
 describe(".dockerignore", () => {
-    // Everything here is either generated, enormous, or secret. `.claude/` is
-    // the correctness one: see the header comment and issue #25.
+    // Everything here is either generated, enormous, or secret. `.claude` is
+    // the correctness one: see the header comment and issue #25. The leading
+    // `/` anchors an entry at the root of the context.
     it.each([
-        ".claude/",
-        ".quak/",
-        "bin/quak",
-        "node_modules",
-        "coverage",
-        "dist",
-        ".vitest-cache/",
-        ".nyc_output/",
-        "*.tsbuildinfo",
+        ".claude",
+        "/.quak",
+        "/bin/quak",
+        "**/node_modules",
+        "/coverage",
+        "/dist",
+        "/.vitest-cache",
+        "/.nyc_output",
+        "/*.tsbuildinfo",
     ])("keeps %s out of the build context", (pattern) => {
         expect(dockerignore).toContain(pattern);
     });
@@ -57,7 +58,7 @@ describe(".dockerignore", () => {
     // The build stage is the final image, so a .git/config sent in would
     // ship the clone's remote URL and any credential in it.
     it("sends .git without its config", () => {
-        expect(dockerignore).toContain(".git/config");
+        expect(dockerignore).toContain("**/.git/config");
     });
 
     // BuildKit lets a `Dockerfile.dockerignore` shadow the root one; such a