diff --git a/scripts/check-phase16.sh b/scripts/check-phase16.sh
new file mode 100755
index 0000000..d3fab31
--- /dev/null
+++ b/scripts/check-phase16.sh
@@ -0,0 +1,402 @@
+#!/usr/bin/env bash
+# Phase 16 fail-closed gate (vue-journal-layer, the grzybyfunkcjonalne.pl site
+# app and its SummerCMS host). Every stage exits non-zero on a failing
+# command; a node --test run that reports "not ok", a failed, skipped, todo or
+# cancelled test, no passing test or a missing named test; a go test run that
+# fails, skips, matches zero tests, prints "no tests to run", misses a named
+# required test or reports a data race; or an SSR smoke that does not end ok.
+# --self-test proves both detectors fail closed on planted inputs. --all runs
+# every stage and must end with "Phase 16 gate passed".
+#
+# The grzyby command tests need Postgres: GRZYBY_TEST_ADMIN_DSN (a
+# maintenance-database DSN whose role has CREATEDB) or Docker for
+# testcontainers. Without either they fail; -short is not final evidence.
+#
+# Environment overrides: PHASE16_LAYER (default ../vue-journal-layer),
+# PHASE16_HOST (default ../sm-grzybyfunkcjonalne-app), PHASE16_APP (default
+# $PHASE16_HOST/vue-grzybyfunkcjonalne-app).
+set -euo pipefail
+
+unset FORCE_COLOR
+
+ROOT="${PHASE16_ROOT:-$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)}"
+LAYER="${PHASE16_LAYER:-$ROOT/../vue-journal-layer}"
+HOST="${PHASE16_HOST:-$ROOT/../sm-grzybyfunkcjonalne-app}"
+APP="${PHASE16_APP:-$HOST/vue-grzybyfunkcjonalne-app}"
+PLUGIN="$HOST/plugins/grzyby"
+
+# One named test per layer test file.
+LAYER_REQUIRE=(
+	"an override replaces one key and keeps the others"
+	"a post path without :slug throws naming journal.routes.post"
+	"listCategories always sends include_empty=1"
+	"getPost returns null for status 404 and statusCode 404"
+	"anything else is a 404 (null)"
+	"Go case vbscript is unsafe"
+	"Go case data in upper case is unsafe"
+	"a custom root category route gives /cordyceps"
+	"without an excerpt the description is the first 160 characters of the body text"
+	"pl and en have identical leaf key sets"
+)
+APP_REQUIRE=(
+	"D-15: every PHP URL form answers the expected status"
+	"static pages win over the root category route (RESEARCH A2)"
+	"D-16: Polish only, without a prefix"
+	"T-16-01: an unsafe post body renders the blocked notice only"
+	"Pitfall 5: SSR fetches forward the visitor X-Forwarded-For"
+	"D-23: NUXT_PUBLIC_GA_ID loads gtag for its id"
+	"D-23: a malformed NUXT_PUBLIC_GA_ID loads no script (T-16-07)"
+	"malformed ids give no scripts"
+	"the FAQ has the 16 live entries with question and answer"
+	"every t('…') key used in app/**/*.vue exists in pl.json or the layer's journal strings"
+)
+HOST_REQUIRE=(
+	TestBootUserTranslateJournal
+	TestCORS
+	TestBackendURIGfadmin
+	TestGrzybyCommandsRegistered
+)
+PLUGIN_REQUIRE=(
+	TestReadFeaturedImageMap
+	TestValidDiskName
+	TestFeaturedImageSourceEscape
+	TestImportFeaturedImages
+	TestImportFeaturedImagesDryRun
+	TestReadCategoryMap
+	TestImportCategories
+)
+
+usage() {
+	cat >&2 <<'EOF'
+usage:
+  check-phase16.sh --self-test
+  check-phase16.sh --layer
+  check-phase16.sh --layer-smoke
+  check-phase16.sh --app
+  check-phase16.sh --host
+  check-phase16.sh --plugin
+  check-phase16.sh --deploy
+  check-phase16.sh --all
+EOF
+	exit 2
+}
+
+# detect_go reads go test -json. Exit 1 fail/build, 2 skip, 3 zero/no-tests,
+# 4 non-JSON, 5 missing required name, 6 data race.
+detect_go() {
+	python3 - "$1" <<'PY'
+import json, os, sys
+path = sys.argv[1]
+require = [n for n in os.environ.get("REQUIRE_TESTS", "").split() if n]
+passed = set()
+failed = []
+with open(path, encoding="utf-8", errors="replace") as fh:
+    for raw in fh:
+        line = raw.strip()
+        if not line.startswith("{"):
+            continue
+        try:
+            ev = json.loads(line)
+        except json.JSONDecodeError:
+            print("refuse: non-json test output", file=sys.stderr)
+            sys.exit(4)
+        action = ev.get("Action")
+        test = ev.get("Test") or ""
+        pkg = ev.get("Package") or ev.get("ImportPath") or ""
+        if action == "build-fail" or (action == "fail" and ev.get("FailedBuild")):
+            print(f"refuse: build failed {pkg}", file=sys.stderr)
+            sys.exit(1)
+        text = ev.get("Output") or ""
+        if action == "output":
+            if "no tests to run" in text:
+                print(f"refuse: no tests to run in {pkg}", file=sys.stderr)
+                sys.exit(3)
+            if "WARNING: DATA RACE" in text:
+                print(f"refuse: data race in {pkg} {test}", file=sys.stderr)
+                sys.exit(6)
+        if action == "skip" and test:
+            print(f"refuse: skipped {pkg} {test}", file=sys.stderr)
+            sys.exit(2)
+        if action == "fail":
+            failed.append(f"{pkg} {test}".strip())
+        if action == "pass" and test:
+            passed.add(test)
+if failed:
+    print("refuse: failed " + ", ".join(failed), file=sys.stderr)
+    sys.exit(1)
+if not passed:
+    print("refuse: zero tests", file=sys.stderr)
+    sys.exit(3)
+missing = [n for n in require if n not in passed]
+if missing:
+    print("refuse: required tests did not pass: " + ", ".join(missing), file=sys.stderr)
+    sys.exit(5)
+PY
+}
+
+# detect_tap reads node --test --test-reporter=tap output. Exit 1 "not ok" or
+# a fail/cancelled count, 2 skip/todo, 3 no pass count or zero passes, 5
+# missing required name. REQUIRE_NAMES holds one test name per line.
+detect_tap() {
+	python3 - "$1" <<'PY'
+import os, re, sys
+path = sys.argv[1]
+require = [n for n in os.environ.get("REQUIRE_NAMES", "").split("\n") if n.strip()]
+passed = set()
+counts = {}
+with open(path, encoding="utf-8", errors="replace") as fh:
+    for raw in fh:
+        line = raw.rstrip("\n")
+        body = line.lstrip()
+        if body.startswith("not ok"):
+            print(f"refuse: {body}", file=sys.stderr)
+            sys.exit(1)
+        m = re.match(r"ok \d+ - (.*?)(\s+#\s*(SKIP|TODO)\b.*)?$", body, re.I)
+        if m:
+            if m.group(2):
+                print(f"refuse: {body}", file=sys.stderr)
+                sys.exit(2)
+            if line == body:
+                passed.add(m.group(1))
+            continue
+        m = re.match(r"# (tests|suites|pass|fail|cancelled|skipped|todo) (\d+)$", line)
+        if m:
+            counts[m.group(1)] = int(m.group(2))
+for key in ("fail", "cancelled"):
+    if counts.get(key, 0) > 0:
+        print(f"refuse: {counts[key]} {key}", file=sys.stderr)
+        sys.exit(1)
+for key in ("skipped", "todo"):
+    if counts.get(key, 0) > 0:
+        print(f"refuse: {counts[key]} {key}", file=sys.stderr)
+        sys.exit(2)
+if counts.get("pass", 0) < 1 or not passed:
+    print("refuse: no passing tests", file=sys.stderr)
+    sys.exit(3)
+missing = [n for n in require if n not in passed]
+if missing:
+    print("refuse: required tests did not pass: " + "; ".join(missing), file=sys.stderr)
+    sys.exit(5)
+PY
+}
+
+go_json() {
+	local dir="$1"
+	shift
+	local log err rc=0 dc=0
+	log="$(mktemp)"
+	err="$(mktemp)"
+	(cd "$dir" && go test -json "$@") >"$log" 2>"$err" || rc=$?
+	detect_go "$log" || dc=$?
+	if [[ "$rc" -ne 0 || "$dc" -ne 0 ]]; then
+		cat "$err" >&2 || true
+		grep -v '^{' "$log" | tail -n 40 >&2 || true
+		rm -f "$log" "$err"
+		echo "refuse: go test $* in $dir (test=$rc detect=$dc)" >&2
+		return 1
+	fi
+	rm -f "$log" "$err"
+}
+
+# node_tap runs `pnpm -C <dir> test` and checks its TAP output.
+node_tap() {
+	local dir="$1" log rc=0 dc=0
+	log="$(mktemp)"
+	pnpm -C "$dir" test >"$log" 2>&1 || rc=$?
+	detect_tap "$log" || dc=$?
+	if [[ "$rc" -ne 0 || "$dc" -ne 0 ]]; then
+		grep -E '^\s*(not ok|# )|Error' "$log" | tail -n 40 >&2 || true
+		rm -f "$log"
+		echo "refuse: pnpm test in $dir (test=$rc detect=$dc)" >&2
+		return 1
+	fi
+	grep -E '^# (tests|pass) ' "$log"
+	rm -f "$log"
+}
+
+# smoke runs a command that must exit 0 and print "smoke-ssr: ok".
+smoke() {
+	local log rc=0
+	log="$(mktemp)"
+	"$@" >"$log" 2>&1 || rc=$?
+	if [[ "$rc" -ne 0 ]] || ! grep -q '^smoke-ssr: ok' "$log"; then
+		tail -n 40 "$log" >&2 || true
+		rm -f "$log"
+		echo "refuse: $* (exit $rc)" >&2
+		return 1
+	fi
+	grep '^smoke-ssr: ok' "$log"
+	rm -f "$log"
+}
+
+expect_go() {
+	local name="$1" want="$2" payload="$3" log dc=0
+	log="$(mktemp)"
+	printf '%s\n' "$payload" >"$log"
+	detect_go "$log" 2>/dev/null || dc=$?
+	rm -f "$log"
+	if [[ "$dc" -ne "$want" ]]; then
+		echo "refuse: self-test go $name: detector exit $dc, want $want" >&2
+		return 1
+	fi
+}
+
+expect_tap() {
+	local name="$1" want="$2" payload="$3" log dc=0
+	log="$(mktemp)"
+	printf '%s\n' "$payload" >"$log"
+	detect_tap "$log" 2>/dev/null || dc=$?
+	rm -f "$log"
+	if [[ "$dc" -ne "$want" ]]; then
+		echo "refuse: self-test tap $name: detector exit $dc, want $want" >&2
+		return 1
+	fi
+}
+
+run_self_test() {
+	bash -n "${BASH_SOURCE[0]}"
+	expect_go pass 0 '{"Action":"pass","Package":"p","Test":"TestImportCategories"}'
+	expect_go fail 1 '{"Action":"pass","Package":"p","Test":"TestA"}
+{"Action":"fail","Package":"p","Test":"TestImportFeaturedImages"}'
+	expect_go package-fail 1 '{"Action":"pass","Package":"p","Test":"TestA"}
+{"Action":"fail","Package":"p"}'
+	expect_go build 1 '{"Action":"build-fail","ImportPath":"p"}'
+	expect_go skip 2 '{"Action":"skip","Package":"p","Test":"TestImportFeaturedImages"}'
+	expect_go zero 3 '{"Action":"pass","Package":"p"}'
+	expect_go no-tests 3 '{"Action":"output","Package":"p","Output":"testing: warning: no tests to run\n"}
+{"Action":"pass","Package":"p"}'
+	expect_go nonjson 4 '{"Action":"pass",'
+	expect_go race 6 '{"Action":"output","Package":"p","Test":"TestA","Output":"WARNING: DATA RACE\n"}
+{"Action":"pass","Package":"p","Test":"TestA"}'
+	REQUIRE_TESTS="TestBackendURIGfadmin TestCORS" expect_go missing-named 5 \
+		'{"Action":"pass","Package":"p","Test":"TestCORS"}'
+	REQUIRE_TESTS="TestImportFeaturedImages" expect_go subtest-is-not-the-test 5 \
+		'{"Action":"pass","Package":"p","Test":"TestImportFeaturedImagesDryRun"}'
+
+	local ok='TAP version 13
+ok 1 - routes ok
+1..1
+# tests 1
+# pass 1
+# fail 0
+# cancelled 0
+# skipped 0
+# todo 0'
+	expect_tap pass 0 "$ok"
+	expect_tap not-ok 1 'TAP version 13
+ok 1 - a
+not ok 2 - b
+# pass 1
+# fail 1'
+	expect_tap nested-not-ok 1 'TAP version 13
+    not ok 1 - sub
+ok 1 - a
+# pass 1
+# fail 0'
+	expect_tap fail-count 1 'ok 1 - a
+# pass 1
+# fail 2'
+	expect_tap cancelled 1 'ok 1 - a
+# pass 1
+# cancelled 1'
+	expect_tap skip-directive 2 'ok 1 - a # SKIP needs db
+# pass 1'
+	expect_tap skipped-count 2 'ok 1 - a
+# pass 1
+# skipped 1'
+	expect_tap todo 2 'ok 1 - a # TODO later
+# pass 1'
+	expect_tap no-pass-line 3 'ok 1 - a'
+	expect_tap zero 3 '# tests 0
+# pass 0
+# fail 0'
+	REQUIRE_NAMES=$'routes ok\nmissing name' expect_tap missing-named 5 "$ok"
+	REQUIRE_NAMES='routes ok' expect_tap named 0 "$ok"
+
+	local flag
+	for flag in --self-test --layer --layer-smoke --app --host --plugin --deploy --all; do
+		grep -q -- "^	$flag)" "${BASH_SOURCE[0]}" || {
+			echo "refuse: missing mode $flag" >&2
+			return 1
+		}
+	done
+	echo "phase16 self-test passed"
+}
+
+require_dir() {
+	[[ -d "$1" ]] || {
+		echo "refuse: $2 $1 not found" >&2
+		return 1
+	}
+}
+
+run_layer() {
+	require_dir "$LAYER" "layer repository"
+	REQUIRE_NAMES="$(printf '%s\n' "${LAYER_REQUIRE[@]}")" node_tap "$LAYER"
+	echo "phase16 layer passed"
+}
+
+run_layer_smoke() {
+	require_dir "$LAYER" "layer repository"
+	pnpm -C "$LAYER" build:playground >/dev/null
+	smoke node "$LAYER/testing/smoke-ssr.mjs" \
+		--output "$LAYER/.playground/.output" \
+		--fixtures "$LAYER/testing/fixtures/acme" \
+		--expect "$LAYER/testing/expect-acme.txt"
+	echo "phase16 layer-smoke passed"
+}
+
+run_app() {
+	require_dir "$APP" "site app"
+	pnpm -C "$APP" install --frozen-lockfile >/dev/null
+	pnpm -C "$APP" build >/dev/null
+	REQUIRE_NAMES="$(printf '%s\n' "${APP_REQUIRE[@]}")" node_tap "$APP"
+	smoke pnpm -C "$APP" smoke:ssr
+	smoke pnpm -C "$APP" smoke:ga
+	echo "phase16 app passed"
+}
+
+run_host() {
+	require_dir "$HOST" "host repository"
+	go -C "$HOST" vet ./...
+	REQUIRE_TESTS="${HOST_REQUIRE[*]}" go_json "$HOST" ./... -count=1 -v -timeout 5m
+	echo "phase16 host passed"
+}
+
+run_plugin() {
+	require_dir "$PLUGIN" "grzyby plugin"
+	go -C "$PLUGIN" vet ./...
+	REQUIRE_TESTS="${PLUGIN_REQUIRE[*]}" go_json "$PLUGIN" ./... -count=1 -v -race -timeout 10m
+	echo "phase16 plugin passed"
+}
+
+run_deploy() {
+	require_dir "$HOST" "host repository"
+	bash "$HOST/scripts/check-deploy.sh"
+	echo "phase16 deploy passed"
+}
+
+run_all() {
+	local stage
+	for stage in self-test layer layer-smoke app host plugin deploy; do
+		if bash "${BASH_SOURCE[0]}" "--$stage"; then
+			echo "PASS $stage"
+		else
+			echo "FAIL $stage"
+			exit 1
+		fi
+	done
+	echo "Phase 16 gate passed"
+}
+
+case "${1:---all}" in
+	--self-test) run_self_test ;;
+	--layer) run_layer ;;
+	--layer-smoke) run_layer_smoke ;;
+	--app) run_app ;;
+	--host) run_host ;;
+	--plugin) run_plugin ;;
+	--deploy) run_deploy ;;
+	--all) run_all ;;
+	*) usage ;;
+esac