The tool runtime's recipe starts FROM the base its manifest declares (novox/hq ADR 0097)

Dockerfile

@@ -1,3 +1,4 @@
+ARG NODE_BASE=node:22-bookworm-slim
 # Three stages, two published images: the one modules are COMPILED in, and the one they RUN in.
 #
 # **They were the same image, and that was a mistake.** A module's recipe starts from this and
@@ -13,7 +14,7 @@
 # docker may carry no buildx.
 
 # ---- deps: node_modules resolved from the mesh's registry, credential and all ----------------
-FROM node:22-bookworm-slim AS deps
+FROM ${NODE_BASE} AS deps
 RUN apt-get update \
       && apt-get install -y --no-install-recommends git ca-certificates \
       && rm -rf /var/lib/apt/lists/*
@@ -26,7 +27,7 @@ COPY .npmrc ./.npmrc
 RUN npm install --no-audit --no-fund
 
 # ---- toolchain: what a module is compiled in, WITHOUT the credential --------------------------
-FROM node:22-bookworm-slim AS toolchain
+FROM ${NODE_BASE} AS toolchain
 WORKDIR /app
 COPY package.json ./
 # The resolved libraries, but not the .npmrc that resolved them.
@@ -45,7 +46,7 @@ FROM toolchain AS lean
 RUN npm prune --omit=dev
 
 # ---- runtime: what a module runs in -----------------------------------------------------------
-FROM node:22-bookworm-slim AS runtime
+FROM ${NODE_BASE} AS runtime
 WORKDIR /app
 COPY package.json ./
 COPY --from=lean /app/node_modules ./node_modules