diff --git a/Dockerfile b/Dockerfile
index 424ee87..bb0a459 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,42 +1,53 @@
-# Lint stage
-# Same image as Dockerfile.lint: change both pins together.
-# golangci/golangci-lint:v2.12.2-alpine, 2026-08-07
-FROM golangci/golangci-lint:v2.12.2-alpine@sha256:91b27804074a0bacea298707f016911e60cf0cdbc6c7bf5ccacb5f0606d18d60 AS lint
+# Lint phase. script/lint builds it alone. The linter is run directly:
+# `make lint` and script/lint are themselves a docker build.
+# golangci/golangci-lint:v2.12.2, 2026-10-04
+FROM golangci/golangci-lint@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240 AS lint
+
+# The linter compiles every package, and govips needs the libvips
+# headers for that. This image is Debian and has no apk, so they come
+# from apt-get rather than script/bootstrap.
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends libvips-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+RUN golangci-lint run --config .golangci.yml ./...
+
+# Test phase. script/test builds it alone.
+# golang:1.25.4-alpine, 2026-02-25
+FROM golang:1.25.4-alpine@sha256:d3f0cf7723f3429e3f9ed846243970b20a2de7bae6a5b66fc5914e228d831bbb AS test
 
 WORKDIR /src
 
-# script/bootstrap installs the build dependencies and downloads the Go
-# modules. Only script/, go.mod and go.sum are copied first, so this
-# layer is reused until one of them changes.
+# script/bootstrap installs the build dependencies (a C compiler and the
+# libvips and libheif headers) and downloads the Go modules.
 COPY script/ ./script/
 COPY go.mod go.sum ./
 RUN script/bootstrap
 
-# Copy source code
 COPY . .
 
-# Tells script/lint it is inside a container, so it runs the linter.
-ENV container=docker
+# Without -v first; on a failure, again with -v for the details, and
+# the step fails even if the second run passes.
+RUN go test -count=1 -timeout 90s -race -cover ./... || \
+    { echo "--- Rerunning with -v for details ---"; \
+      go test -count=1 -timeout 90s -race -v ./...; exit 1; }
 
-# Run formatting check and linter. script/cibuild and script/docker pass
-# a new CHECK_EPOCH on every run, and each check step names it in its
-# command, so a new value reruns the step instead of reusing a cached
-# success that checked nothing. A plain `docker build .` leaves it empty
-# and reuses the check steps only for an identical build context.
-ARG CHECK_EPOCH
-RUN echo "check epoch: ${CHECK_EPOCH}" && make fmt-check
-RUN echo "check epoch: ${CHECK_EPOCH}" && make lint
-
-# Build stage
+# Build stage. Nothing is wanted from the two phases above: these copies
+# make BuildKit build them first, so this stage runs only when lint and
+# test passed.
 # golang:1.25.4-alpine, 2026-02-25
 FROM golang:1.25.4-alpine@sha256:d3f0cf7723f3429e3f9ed846243970b20a2de7bae6a5b66fc5914e228d831bbb AS builder
 
-# Depend on lint stage passing
 COPY --from=lint /src/go.sum /dev/null
+COPY --from=test /src/go.sum /dev/null
 
 WORKDIR /src
 
-# Build dependencies and Go modules, as in the lint stage
+# Build dependencies and Go modules, as in the test phase
 COPY script/ ./script/
 COPY go.mod go.sum ./
 RUN script/bootstrap
@@ -44,12 +55,8 @@ RUN script/bootstrap
 # Copy source code
 COPY . .
 
-# Run tests; a new CHECK_EPOCH reruns them, as in the lint stage.
-ARG CHECK_EPOCH
-RUN echo "check epoch: ${CHECK_EPOCH}" && make test
-
 # VERSION is declared here, not earlier: a new value reruns only the
-# build, not script/bootstrap or the tests. Given none, the version is
+# build, not script/bootstrap. Given none, the version is
 # `git describe --tags --always` of the .git in the build context (git
 # comes from script/bootstrap): the tag on a tagged commit, tag-N-gHASH
 # after one, the short commit when no tag is reachable. A context that
@@ -68,7 +75,8 @@ RUN version="${VERSION:-$(git describe --tags --always)}"; \
         -ldflags "-s -w -X main.Version=${version}" \
         -o /pixad ./cmd/pixad
 
-# Runtime stage
+# Runtime stage, and the last one: a plain `docker build .` builds this
+# stage and what it depends on, and nothing else.
 # alpine:3.21, 2026-02-25
 FROM alpine:3.21@sha256:c3f8e73fdb79deaebaa2037150150191b9dcbfba68b4a46d70103204c53f4709
 
diff --git a/Dockerfile.lint b/Dockerfile.lint
deleted file mode 100644
index 41e350b..0000000
--- a/Dockerfile.lint
+++ /dev/null
@@ -1,34 +0,0 @@
-# Dockerfile.lint: the container script/lint builds to run golangci-lint,
-# which is never installed on the host. Pinned to the same image as the
-# Dockerfile lint stage: change both pins together, or the two run
-# different linter versions.
-#
-# golangci/golangci-lint:v2.12.2-alpine, 2026-08-07
-FROM golangci/golangci-lint:v2.12.2-alpine@sha256:91b27804074a0bacea298707f016911e60cf0cdbc6c7bf5ccacb5f0606d18d60
-
-WORKDIR /src
-
-# pixa is CGO/libvips: the type-aware linters compile every package, so
-# this image needs the same C libraries the build does. script/bootstrap
-# installs them and downloads the Go modules. Only script/, go.mod and
-# go.sum are copied first; they settle this layer's result, so it may
-# safely be reused between runs.
-COPY script/ ./script/
-COPY go.mod go.sum ./
-RUN script/bootstrap
-
-COPY . .
-
-# Tells script/lint it is inside a container, so it runs the linter.
-ENV container=docker
-
-# script/lint passes a different CACHEBUST on every run, and BuildKit
-# keys every RUN after this ARG on its value, so the lint step always
-# runs instead of returning a cached success that linted nothing.
-#
-# Go's and golangci-lint's caches (/root/.cache, hundreds of MB) go on a
-# tmpfs that is discarded after the step. Written into the layer, they
-# would pile up as build cache on every run, since no later run, with
-# its new CACHEBUST, can reuse that layer.
-ARG CACHEBUST
-RUN --mount=type=tmpfs,target=/root/.cache script/lint
diff --git a/Makefile b/Makefile
index 708d5e5..8b1de2a 100644
--- a/Makefile
+++ b/Makefile
@@ -32,11 +32,11 @@ fmt-check:
 fmt:
 	@script/fmt
 
-# Run linter
+# Run linter (the lint phase of the Dockerfile)
 lint:
 	@script/lint
 
-# Run tests (30-second timeout)
+# Run tests (the test phase of the Dockerfile)
 test:
 	@script/test
 
@@ -59,20 +59,20 @@ docker:
 docker-smoke:
 	@script/docker-smoke
 
-# Build Docker image tagged pixad:$(VERSION) and pixad:latest
+# Build Docker image as `make docker` does, and also tag it pixa:$(VERSION)
 docker-versioned:
-	docker build --build-arg VERSION=$(VERSION) -t pixad:$(VERSION) -t pixad:latest .
+	@script/docker
+	docker tag pixa pixa:$(VERSION)
 
-# Run tests in Docker (needed for CGO/libvips)
+# Run tests in Docker, as `make test` does
 docker-test:
-	docker build --target builder --build-arg VERSION=$(VERSION) -t pixad-builder .
-	docker run --rm pixad-builder sh -c "CGO_ENABLED=1 GOTOOLCHAIN=auto go test -v ./..."
+	@script/test
 
 # Run local dev server in Docker
 devserver: docker-versioned devserver-stop
 	docker run -d --name pixad-dev -p 8080:8080 \
 		-v $(CURDIR)/config.dev.yml:/etc/pixa/config.yml:ro \
-		pixad:latest
+		pixa:latest
 	@echo "pixad running at http://localhost:8080"
 
 # Stop dev server
diff --git a/README.md b/README.md
index 8597c53..d73de7a 100644
--- a/README.md
+++ b/README.md
@@ -568,22 +568,31 @@ them. We provide:
 - `script/setup` — make a fresh clone ready for development
   (bootstrap, then install-precommit)
 - `script/projectname` — output the project name ("pixa")
-- `script/test` — run the test suite
-- `script/lint` — run golangci-lint, always in a container (builds
-  `Dockerfile.lint` when run outside one)
+- `script/test` — run the test suite: build the `test` phase of the
+  `Dockerfile`, tagged `pixa-test`
+- `script/lint` — run golangci-lint: build the `lint` phase of the `Dockerfile`,
+  tagged `pixa-lint`; the linter never runs on the host
 - `script/fmt` — format all code (writes)
-- `script/fmt-check` — check formatting (read-only)
+- `script/fmt-check` — check formatting (read-only), on the host
 - `script/check` — run test, lint, and fmt-check
-- `script/docker` — build the Docker image tagged via `script/projectname`
+- `script/docker` — build the Docker image tagged via `script/projectname`, with
+  the version from `git describe`; the image's build stage depends on the `lint`
+  and `test` phases, so this runs them too
 - `script/docker-smoke` — build the image, start it, wait for it to be healthy
-- `script/cibuild` — CI entrypoint: `docker build .` with a new
-  `CHECK_EPOCH` on every run, so the Dockerfile's checks run instead of
-  coming from the build cache, and a green run implies a green repo
+- `script/cibuild` — CI entrypoint: run `script/bootstrap` (which installs Go
+  and the libvips libraries on the host), then `script/check`, then build the
+  image as `script/docker` does
 - `script/precommit` — pre-commit checks (`go mod tidy` guard, then
   `script/check`)
 - `script/install-precommit` — install the git pre-commit hook that
   runs `script/precommit`
 
+Every `docker build` in these scripts passes `--no-cache`, so the lint and test
+phases run on every build instead of coming from the build cache.
+`script/check`, `script/cibuild`, `script/docker`, `script/lint`, `script/test`,
+`script/setup` and `script/install-precommit` are the standard copies from
+`sneak/prompts`, kept identical to them.
+
 ## TODO
 
 See [TODO.md](TODO.md) for the full prioritized task list.
diff --git a/TODO.md b/TODO.md
index fefbc63..42a36d4 100644
--- a/TODO.md
+++ b/TODO.md
@@ -31,6 +31,21 @@ P2: security: per-IP rate limiting on the image routes
 
 # Completed Steps
 
+- 2026-10-04 lint and tests run as the `lint` and `test` phases of the
+  `Dockerfile`, built with `--no-cache` (closes #202): `script/check`,
+  `script/cibuild`, `script/docker`, `script/lint`, `script/test`,
+  `script/setup` and `script/install-precommit` are now the copies from
+  `sneak/prompts` `main`, unchanged. The `lint` phase runs golangci-lint from
+  the image `REPO_POLICIES.md` names, with `libvips-dev` from `apt-get`; the
+  `test` phase runs the tests with a 90-second timeout; the build stage depends
+  on both. `Dockerfile.lint` and the `CHECK_EPOCH` build argument are gone, the
+  formatting check runs on the host, and `make docker-versioned` and
+  `make docker-test` call the scripts. `script/bootstrap`, `script/fmt`,
+  `script/fmt-check`, `script/precommit` and `script/projectname` stay pixa's
+  own: Go and libvips, `gofmt`, the `go mod tidy` guard, the name. The stage
+  that compiles still takes the version from `git describe` when no `VERSION` is
+  given, per https://git.eeqj.de/sneak/pixa/issues/166, so the copied scripts'
+  comment that `.dockerignore` leaves out `.git` does not hold for pixa.
 - 2026-10-04 local config files stay out of the Docker build context (closes
   #211): `.dockerignore` now leaves out `config.yaml` and `config.dev.yml` in
   every directory and in any letter case, the local config files `.gitignore`
diff --git a/script/bootstrap b/script/bootstrap
index 54c04ea..d163746 100755
--- a/script/bootstrap
+++ b/script/bootstrap
@@ -4,11 +4,11 @@
 # installed tools are skipped. Base tooling comes from nix, apt, brew,
 # or apk (detected in that order); assumes NOTHING is present (not git,
 # make, or go). The linter is never installed on the host: golangci-lint
-# runs only inside a container, Dockerfile.lint or the Dockerfile lint
-# stage (see script/lint). A C compiler and the CGO image libraries
-# (pkg-config, vips, libheif) are installed for the govips bindings.
-# Both Dockerfiles run this script too, so their build dependencies are
-# the ones listed here.
+# runs only in the lint phase of the Dockerfile (see script/lint). A C
+# compiler and the CGO image libraries (pkg-config, vips, libheif) are
+# installed for the govips bindings. The Dockerfile's test phase and
+# build stage run this script too, so their build dependencies are the
+# ones listed here.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
diff --git a/script/check b/script/check
index cc046f7..92875f7 100755
--- a/script/check
+++ b/script/check
@@ -1,7 +1,8 @@
 #!/bin/sh
 # script/check: run all checks (test, lint, fmt-check). Our own
-# extension to scripts-to-rule-them-all. Must not modify any files.
-# Generic: usually needs no adaptation.
+# 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)"
diff --git a/script/cibuild b/script/cibuild
index 948134c..688299f 100755
--- a/script/cibuild
+++ b/script/cibuild
@@ -1,18 +1,29 @@
 #!/bin/sh
-# script/cibuild: run the CI build. The Dockerfile runs the checks
-# (make fmt-check, lint, test) as build steps. This script passes a new
-# CHECK_EPOCH on every run, so Docker runs those steps instead of
-# reusing cached results: a successful run means the checks ran and
-# passed on this tree. Generic: needs no adaptation. The Gitea workflow
-# runs this on push.
+# 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.
 set -eu
 
-ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    epoch="$(date +%s)$$"
-    docker build --build-arg CHECK_EPOCH="$epoch" .
+    "$SCRIPT_DIR/bootstrap"
+    "$SCRIPT_DIR/check"
+    # Own line: a failing command substitution inside an argument does
+    # not trip `set -e`, so the inline form degrades silently to an
+    # empty constant. VERSION is computed here because .dockerignore
+    # excludes .git, so `git describe` in a build stage yields an empty
+    # version without failing.
+    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
+    [ -n "$version" ] || version="unknown"
+    docker build --no-cache \
+        --build-arg VERSION="$version" \
+        -t "$("$SCRIPT_DIR/projectname")" .
 }
 
 main "$@"
diff --git a/script/docker b/script/docker
index b9907d8..c4688e8 100755
--- a/script/docker
+++ b/script/docker
@@ -1,9 +1,8 @@
 #!/bin/sh
 # script/docker: build the Docker image tagged with the project name.
-# Identical in all repos; the tag comes from script/projectname. Like
-# script/cibuild, it passes a new CHECK_EPOCH, so the build runs the
-# checks instead of reusing cached results. Generic: needs no
-# adaptation.
+# Identical in all repos; the tag comes from script/projectname.
+# --no-cache because the gate phases the final stage depends on are RUN
+# steps, and a cached one is a check that did not run.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -11,8 +10,15 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    epoch="$(date +%s)$$"
-    docker build --build-arg CHECK_EPOCH="$epoch" \
+    # Own line: a failing command substitution inside an argument does
+    # not trip `set -e`, so the inline form degrades silently to an
+    # empty constant. VERSION is computed here because .dockerignore
+    # excludes .git, so `git describe` in a build stage yields an empty
+    # version without failing.
+    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
+    [ -n "$version" ] || version="unknown"
+    docker build --no-cache \
+        --build-arg VERSION="$version" \
         -t "$("$SCRIPT_DIR/projectname")" .
 }
 
diff --git a/script/install-precommit b/script/install-precommit
index 49da044..bef6406 100755
--- a/script/install-precommit
+++ b/script/install-precommit
@@ -1,13 +1,13 @@
 #!/bin/sh
 # script/install-precommit: install the git pre-commit hook that runs
 # script/precommit. Our own extension to scripts-to-rule-them-all.
-# Generic: needs no adaptation.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
+    hook=".git/hooks/pre-commit"
     printf '#!/bin/sh\nset -e\nscript/precommit\n' > .git/hooks/pre-commit
     chmod +x .git/hooks/pre-commit
     echo "pre-commit hook installed: runs script/precommit"
diff --git a/script/lint b/script/lint
index 96aa46d..2d8b075 100755
--- a/script/lint
+++ b/script/lint
@@ -1,37 +1,23 @@
 #!/bin/sh
-# script/lint: run golangci-lint over the whole tree. This is the only
-# way the linter is run, everywhere; it is never installed on the host.
+# script/lint: run the linter. Linting is a phase of the Dockerfile and
+# this builds that phase alone; the linter is never installed or run on
+# a developer host, where a shared result cache and a host-global lock
+# make its answer untrustworthy.
 #
-# Inside a container it runs the linter. Anywhere else it builds
-# Dockerfile.lint, whose last step runs this script again inside that
-# container.
-#
-# Dockerfile.lint and the Dockerfile lint stage set container=docker
-# (the systemd convention for marking a container) to say where we are.
-# /.dockerenv cannot: it is missing inside build steps, and present on
-# hosts that are themselves containers.
+# The phase is not the last stage in the file, so it is built only when
+# --target names it. --no-cache because a cached lint layer is a lint
+# that did not run. The tag makes each build replace the previous image
+# instead of leaving a dangling one behind.
 set -eu
 
-ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    if [ "${container:-}" = docker ]; then
-        # `golangci-lint config verify` is not run: it fetches its JSON
-        # schema over an unpinned live HTTPS call, which REPO_POLICIES.md
-        # forbids.
-        echo "Running linter..."
-        golangci-lint run --config .golangci.yml ./...
-    else
-        # A new CACHEBUST on every run means the lint step is never
-        # served from cache (see Dockerfile.lint). The cacheonly output
-        # leaves no image behind.
-        docker build \
-            --progress=plain \
-            --build-arg CACHEBUST="$(date +%s)-$$" \
-            --output=type=cacheonly \
-            -f Dockerfile.lint .
-    fi
+    docker build --no-cache \
+        --target lint \
+        -t "$("$SCRIPT_DIR/projectname")-lint" .
 }
 
 main "$@"
diff --git a/script/setup b/script/setup
index 53327ba..4cc5b6b 100755
--- a/script/setup
+++ b/script/setup
@@ -1,7 +1,6 @@
 #!/bin/sh
 # script/setup: set up the repo for development after a fresh clone:
-# installs dependencies (script/bootstrap) and the git pre-commit hook.
-# Add any repo-specific initialization (db init, .env template) here.
+# installs dependencies and the git pre-commit hook.
 set -eu
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
diff --git a/script/test b/script/test
index c0bcc75..cd239f2 100755
--- a/script/test
+++ b/script/test
@@ -1,27 +1,19 @@
 #!/bin/sh
-# script/test: run the test suite. CGO dependencies (pkg-config, vips,
-# libheif) come from nix-shell when not already available (e.g. inside
-# a Docker build or an existing nix-shell).
+# script/test: run the test suite. Testing is a phase of the Dockerfile
+# and this builds that phase alone, on the same terms as script/lint:
+# --target because a phase that is not the last stage is built only when
+# named, --no-cache because a cached test layer is a test that did not
+# run, and a tag so each build replaces the previous image.
 set -eu
 
-ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
-
-run_with_cgo_deps() {
-    if command -v pkg-config >/dev/null 2>&1; then
-        sh -c "$1"
-    else
-        nix-shell -p pkg-config vips libheif git --run "$1"
-    fi
-}
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    echo "Running tests..."
-    # Run without -v first for clean output on success; on failure rerun
-    # with -v for full diagnostics, then exit non-zero (REPO_POLICIES.md
-    # conditional-verbose-rerun pattern). The first run already proved the
-    # tests broken, so the build fails even if the rerun happens to pass.
-    run_with_cgo_deps "CGO_ENABLED=1 go test -timeout 30s -race -cover ./... || { echo '--- Rerunning with -v for details ---'; CGO_ENABLED=1 go test -timeout 30s -race -v ./...; exit 1; }"
+    docker build --no-cache \
+        --target test \
+        -t "$("$SCRIPT_DIR/projectname")-test" .
 }
 
 main "$@"