diff --git a/Dockerfile b/Dockerfile
index 80fa167..d0a2a1f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -60,13 +60,14 @@ COPY --from=build /src/container/progress.mjs ./container/progress.mjs
 RUN mkdir -p /app/release \
   && chmod 0555 /app/runtime/wasm-oj-compiler /app/runtime/wasm-oj-runner \
   && chmod 0444 /app/container/server.mjs /app/container/identity.mjs /app/container/generate-identity.mjs /app/container/tree-digest.mjs /app/container/submission-result.mjs /app/container/progress.mjs \
+  && chmod -R a+rX /app \
   && chmod -R a-w /app \
   && chmod u+w /app/release \
   && WASM_OJ_RELEASE_ID="$WASM_OJ_RELEASE_ID" \
     WASM_OJ_GIT_COMMIT="$WASM_OJ_GIT_COMMIT" \
     node /app/container/generate-identity.mjs \
   && chmod a-w /app/release /app/release/container-identity.json \
-  && node -e "import('/app/container/identity.mjs').then(async m => { await m.loadEmbeddedContainerIdentity(); })" \
+  && runuser -u wasmoj -- node --input-type=module -e "const dependencies = ['@wasm-oj/core', '@wasm-oj/server', '@wasm-oj/toolchain-clang', '@wasm-oj/toolchain-go', '@wasm-oj/toolchain-javascript', '@wasm-oj/toolchain-python', '@wasm-oj/toolchain-rust']; await Promise.all(dependencies.map((dependency) => import(dependency))); const { loadEmbeddedContainerIdentity } = await import('/app/container/identity.mjs'); await loadEmbeddedContainerIdentity();" \
   && runuser -u wasmoj -- node -e "const fs=require('node:fs/promises');const targets=['/app/release/container-identity.json','/app/runtime/wasm-oj-compiler','/app/runtime/wasm-oj-runner'];Promise.all(targets.flatMap((p)=>[fs.access(p,2).then(()=>{throw new Error('wasmoj can write '+p)},()=>{}),fs.unlink(p).then(()=>{throw new Error('wasmoj can delete '+p)},(error)=>{if(!['EACCES','EPERM'].includes(error.code))throw error})])).catch((error)=>{console.error(error);process.exit(1)})"
 USER wasmoj
 ENV NODE_ENV=production
diff --git a/scripts/container-build-context.test.mjs b/scripts/container-build-context.test.mjs
index c56a60c..419e388 100644
--- a/scripts/container-build-context.test.mjs
+++ b/scripts/container-build-context.test.mjs
@@ -41,3 +41,31 @@ test("judge Dockerfile fails closed if generated state still enters the context"
   assert.match(audit, /-name '\.wasm-oj-build-\*'/u);
   assert.match(audit, /-lname '\*\/tmp\/\*'/u);
 });
+
+test("judge image exposes its immutable runtime graph to wasmoj before committing the image", async () => {
+  const dockerfile = await readFile(new URL("../Dockerfile", import.meta.url), "utf8");
+  const grantReadIndex = dockerfile.indexOf("chmod -R a+rX /app");
+  const removeWriteIndex = dockerfile.indexOf("chmod -R a-w /app");
+  const runtimeSmokeIndex = dockerfile.indexOf("runuser -u wasmoj -- node --input-type=module");
+  const finalUserIndex = dockerfile.indexOf("USER wasmoj");
+
+  assert.ok(grantReadIndex >= 0, "the copied runtime tree must be readable and traversable by wasmoj");
+  assert.ok(removeWriteIndex > grantReadIndex, "read/traverse repair must happen before the immutable write fence");
+  assert.ok(runtimeSmokeIndex > removeWriteIndex, "runtime imports must execute after permission hardening");
+  assert.ok(finalUserIndex > runtimeSmokeIndex, "runtime imports must execute during the image build");
+
+  const runtimeSmoke = dockerfile.slice(runtimeSmokeIndex, finalUserIndex);
+  for (const packageName of [
+    "@wasm-oj/core",
+    "@wasm-oj/server",
+    "@wasm-oj/toolchain-clang",
+    "@wasm-oj/toolchain-go",
+    "@wasm-oj/toolchain-javascript",
+    "@wasm-oj/toolchain-python",
+    "@wasm-oj/toolchain-rust",
+  ]) {
+    assert.ok(runtimeSmoke.includes(`'${packageName}'`), `${packageName} must be imported as wasmoj`);
+  }
+  assert.match(runtimeSmoke, /loadEmbeddedContainerIdentity\(\)/u);
+  assert.doesNotMatch(runtimeSmoke, /container\/server\.mjs/u);
+});