chore: declare a supported Node.js range on the published packages

core/package.json

@@ -8,6 +8,9 @@
     "type": "git",
     "url": "https://github.com/google/adk-js"
   },
+  "engines": {
+    "node": ">=22.12.0"
+  },
   "files": [
     "package.json",
     "README.md",

dev/package.json

@@ -8,6 +8,9 @@
     "type": "git",
     "url": "https://github.com/google/adk-js"
   },
+  "engines": {
+    "node": ">=22.12.0"
+  },
   "files": [
     "package.json",
     "README.md",

integrations/package.json

@@ -8,6 +8,9 @@
     "type": "git",
     "url": "https://github.com/google/adk-js"
   },
+  "engines": {
+    "node": ">=22.12.0"
+  },
   "files": [
     "package.json",
     "README.md",

tests/integration/package_manifests/engines_test.ts

@@ -0,0 +1,41 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import {readFile} from 'node:fs/promises';
+import path from 'node:path';
+import {describe, expect, it} from 'vitest';
+
+/**
+ * Workspace directories whose package.json is published to npm. The root
+ * manifest is excluded: it is the workspace container, not a deliverable.
+ */
+const PUBLISHED_WORKSPACES = ['core', 'dev', 'integrations'];
+
+/**
+ * Consumer-facing Node.js floor. 22.12.0 is the lowest release on a supported
+ * LTS line that satisfies every engine constraint in the production dependency
+ * closure. All three published manifests must agree on it.
+ */
+const EXPECTED_NODE_RANGE = '>=22.12.0';
+
+interface Manifest {
+  name?: string;
+  engines?: {node?: string};
+}
+
+async function readManifest(workspace: string): Promise<Manifest> {
+  const manifestPath = path.join(process.cwd(), workspace, 'package.json');
+  return JSON.parse(await readFile(manifestPath, 'utf8')) as Manifest;
+}
+
+describe('published package manifests', () => {
+  it.each(PUBLISHED_WORKSPACES)(
+    '%s declares the shared engines.node range',
+    async (workspace) => {
+      const manifest = await readManifest(workspace);
+      expect(manifest.engines?.node).toBe(EXPECTED_NODE_RANGE);
+    },
+  );
+});