diff --git a/.gitea/workflows/docker-publish.yml b/.gitea/workflows/docker-publish.yml
index ff65090..986f729 100644
--- a/.gitea/workflows/docker-publish.yml
+++ b/.gitea/workflows/docker-publish.yml
@@ -543,7 +543,12 @@ 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 +611,12 @@ 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:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0af97aa..7dd88da 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -56,9 +56,15 @@ 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_${NODE_VERSION}.x`). agent-browser
-0.36.0 declares `engines.node >=24`, but that field is vestigial for the
-artifact actually shipped: the image's own 0.35.2 declares the same floor and
-runs fine on 22.23.2 as a prebuilt aarch64 ELF. The reason to wait is
+0.36.0 declares `engines.node >=24.0.0`, but that field is vestigial for the
+artifact actually shipped: `/usr/bin/agent-browser` is the prebuilt aarch64 ELF
+`bin/agent-browser-linux-arm64`, invoked directly and never through node, so npm's
+engines floor is never enforced at runtime — verified running under 22.23.2 in
+this image. (Corrected 2026-09-07: this paragraph originally said "the image's own
+0.35.2 declares the same floor". That was wrong and incoherent — it contrasted
+0.36.0 against a 0.35.2 that does not exist in the image. There is exactly one
+agent-browser present, `/usr/lib/node_modules/agent-browser` at 0.36.0. The
+argument is unaffected; only the version was wrong.) The reason to wait is
 attribution, not compatibility — this release already moves pi a minor,
 mempalace a minor and bakes a Studio RC, so adding a node major would leave four
 suspects if the image misbehaves. Worth doing as its own release with the smoke
diff --git a/scripts/smoke-test.sh b/scripts/smoke-test.sh
index 5c91d61..4eb1516 100755
--- a/scripts/smoke-test.sh
+++ b/scripts/smoke-test.sh
@@ -5,6 +5,7 @@
 #
 # Verifies:
 #   - pi binary present and (if EXPECTED_PI_VERSION set) matches CI's resolved version
+#   - node MAJOR matches Dockerfile.base's ARG NODE_VERSION (if EXPECTED_NODE_MAJOR set)
 #   - mempalace core matches the audited pin (if EXPECTED_MEMPALACE_VERSION set)
 #   - new v1.0.0 base additions (pandoc, graphviz, imagemagick, yq, tealdeer)
 #   - typst PDF engine for pandoc (v1.4.0) — `pandoc --pdf-engine=typst`
@@ -91,7 +92,18 @@ if [ -n "${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"
 run "aws"             "aws --version"
 run "uv"              "uv --version"