diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6b18fcd..0b679f4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,6 +24,8 @@ jobs:
         with:
           node-version: ${{ matrix.node }}
           cache: npm
+      - if: matrix.node == 24
+        run: npm install --global npm@12.0.1
       - run: npm ci
       - run: npm run typecheck
       - run: npm run lint
@@ -32,8 +34,7 @@ jobs:
       - run: npm run test:coverage
       - run: npm run build
       - run: npm run test:mcp:packed
-      - if: matrix.node == 22
-        run: npm run test:packages:packed
+      - run: npm run test:packages:packed
       - run: npm run check:mcp:client-skill
       - run: npm run check:mcp:examples
       - run: npm run check:skill
diff --git a/package.json b/package.json
index bb334c0..0120700 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
     "size:check": "node scripts/check-package-size.mjs",
     "audit:high": "npm audit --audit-level=high",
     "check:workflows": "node scripts/check-release-workflows.mjs",
-    "test:release-supply-chain": "node --test tests/release-supply-chain.test.mjs",
+    "test:release-supply-chain": "node --test tests/release-supply-chain.test.mjs tests/npm-pack-output.test.mjs",
     "check:mcp-registry": "node scripts/check-mcp-registry-metadata.mjs",
     "check:api-docs": "node scripts/check-api-docs.mjs",
     "check:docs": "node scripts/check-public-docs.mjs",
diff --git a/scripts/check-release-workflows.mjs b/scripts/check-release-workflows.mjs
index 34f7013..ff2e4de 100644
--- a/scripts/check-release-workflows.mjs
+++ b/scripts/check-release-workflows.mjs
@@ -45,6 +45,16 @@ for (const command of [
 ]) {
   assert.ok(ci.includes(`run: ${command}`), `CI must run ${command}`);
 }
+assert.match(
+  ci,
+  /- if: matrix\.node == 24\n\s+run: npm install --global npm@12\.0\.1/,
+  'Node 24 CI must use the exact npm CLI pinned by the release workflow',
+);
+assert.match(
+  ci,
+  /- run: npm run test:packages:packed/,
+  'Every supported Node CI job must exercise the complete packed-package suite',
+);
 
 const proof = workflows.find(({ path }) => path.endsWith('/prove-mcp-published.yml'))?.body ?? '';
 for (const input of ['expected_version', 'expected_integrity', 'expected_git_head']) {
diff --git a/scripts/lib/npm-pack-output.mjs b/scripts/lib/npm-pack-output.mjs
new file mode 100644
index 0000000..10c347e
--- /dev/null
+++ b/scripts/lib/npm-pack-output.mjs
@@ -0,0 +1,48 @@
+import assert from 'node:assert/strict';
+
+function parseJsonTail(output) {
+  const offsets = [0];
+  for (let index = 0; index < output.length; index += 1) {
+    if (output[index] === '\n') {
+      offsets.push(index + 1);
+    }
+  }
+
+  for (const offset of offsets.reverse()) {
+    const candidate = output.slice(offset).trim();
+    if (!candidate.startsWith('[') && !candidate.startsWith('{')) {
+      continue;
+    }
+    try {
+      return JSON.parse(candidate);
+    } catch {
+      // Lifecycle output may contain earlier JSON-looking lines. Keep searching for the final result.
+    }
+  }
+  return undefined;
+}
+
+export function parseNpmPackArtifacts(output, workspace) {
+  const parsed = parseJsonTail(output);
+  assert.notEqual(parsed, undefined, `Could not parse npm pack JSON output for ${workspace}`);
+
+  let artifacts;
+  if (Array.isArray(parsed)) {
+    artifacts = parsed;
+  } else {
+    assert(
+      parsed && typeof parsed === 'object' && Object.hasOwn(parsed, workspace),
+      `Expected npm pack output for ${workspace}`,
+    );
+    assert.equal(Object.keys(parsed).length, 1, `Expected one packed artifact for ${workspace}`);
+    artifacts = [parsed[workspace]];
+  }
+
+  assert.equal(artifacts.length, 1, `Expected one packed artifact for ${workspace}`);
+  assert(
+    artifacts[0] && typeof artifacts[0] === 'object',
+    `Expected one packed artifact for ${workspace}`,
+  );
+  assert.equal(artifacts[0].name, workspace, `Packed the wrong workspace for ${workspace}`);
+  return artifacts;
+}
diff --git a/scripts/pack-release-artifacts.mjs b/scripts/pack-release-artifacts.mjs
index 2c27994..bb5cb39 100644
--- a/scripts/pack-release-artifacts.mjs
+++ b/scripts/pack-release-artifacts.mjs
@@ -5,6 +5,8 @@ import { mkdir, readFile, writeFile } from 'node:fs/promises';
 import { dirname, resolve } from 'node:path';
 import { promisify } from 'node:util';
 
+import { parseNpmPackArtifacts } from './lib/npm-pack-output.mjs';
+
 const execFileAsync = promisify(execFile);
 const argumentsByName = new Map();
 for (let index = 2; index < process.argv.length; index += 2) {
@@ -47,9 +49,7 @@ async function pack(entry) {
   const { stdout } = await execFileAsync(command.command, command.args, {
     maxBuffer: 20 * 1_024 * 1_024,
   });
-  const jsonStart = stdout.lastIndexOf('\n[');
-  const packed = JSON.parse(jsonStart === -1 ? stdout : stdout.slice(jsonStart + 1));
-  assert.equal(packed.length, 1, `expected one artifact for ${entry.name}`);
+  const packed = parseNpmPackArtifacts(stdout, entry.name);
   const artifact = packed[0];
   assert.equal(artifact.name, entry.name, `packed the wrong workspace for ${entry.name}`);
   assert.equal(artifact.version, entry.version, `${entry.name} packed at the wrong version`);
diff --git a/scripts/test-mcp-packed.mjs b/scripts/test-mcp-packed.mjs
index ed5e5a5..0ae5d03 100644
--- a/scripts/test-mcp-packed.mjs
+++ b/scripts/test-mcp-packed.mjs
@@ -12,6 +12,8 @@ import { Client } from '@modelcontextprotocol/sdk/client/index.js';
 import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
 import { JSONRPCMessageSchema, LATEST_PROTOCOL_VERSION } from '@modelcontextprotocol/sdk/types.js';
 
+import { parseNpmPackArtifacts } from './lib/npm-pack-output.mjs';
+
 const execFileAsync = promisify(execFile);
 const root = resolve(dirname(fileURLToPath(import.meta.url)), '..');
 const workspaces = [
@@ -91,9 +93,7 @@ async function packWorkspace(workspace, destination, cache) {
     ['pack', '--workspace', workspace, '--json', '--pack-destination', destination],
     { cwd: root, env: commandEnvironment(cache), maxBuffer: 10 * 1024 * 1024 },
   );
-  const jsonStart = stdout.lastIndexOf('\n[');
-  const results = JSON.parse(jsonStart === -1 ? stdout : stdout.slice(jsonStart + 1));
-  assert.equal(results.length, 1, `Expected one packed artifact for ${workspace}`);
+  const results = parseNpmPackArtifacts(stdout, workspace);
   return results[0];
 }
 
diff --git a/scripts/test-release-artifacts.mjs b/scripts/test-release-artifacts.mjs
index 4149c05..2c2b2aa 100644
--- a/scripts/test-release-artifacts.mjs
+++ b/scripts/test-release-artifacts.mjs
@@ -7,6 +7,8 @@ import { dirname, join, resolve } from 'node:path';
 import { promisify } from 'node:util';
 import { fileURLToPath } from 'node:url';
 
+import { parseNpmPackArtifacts } from './lib/npm-pack-output.mjs';
+
 const execFileAsync = promisify(execFile);
 const root = resolve(dirname(fileURLToPath(import.meta.url)), '..');
 const packages = [
@@ -67,9 +69,7 @@ async function packWorkspace(packageName, destination, environment) {
     ['pack', '--workspace', packageName, '--json', '--pack-destination', destination],
     { env: environment },
   );
-  const jsonStart = stdout.lastIndexOf('\n[');
-  const result = JSON.parse(jsonStart === -1 ? stdout : stdout.slice(jsonStart + 1));
-  assert.equal(result.length, 1, `Expected one packed artifact for ${packageName}`);
+  const result = parseNpmPackArtifacts(stdout, packageName);
   assert.equal(result[0].name, packageName, `Packed the wrong workspace for ${packageName}`);
   assert(
     result[0].files.some((file) => file.path === 'package.json'),
diff --git a/tests/npm-pack-output.test.mjs b/tests/npm-pack-output.test.mjs
new file mode 100644
index 0000000..3fd5bd7
--- /dev/null
+++ b/tests/npm-pack-output.test.mjs
@@ -0,0 +1,52 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+
+import { parseNpmPackArtifacts } from '../scripts/lib/npm-pack-output.mjs';
+
+const artifact = {
+  name: '@buzzr/mcp',
+  version: '5.1.0',
+  filename: 'buzzr-mcp-5.1.0.tgz',
+  files: [{ path: 'package.json', mode: 0o644 }],
+};
+
+test('parses the npm 10 and npm 11 array response after lifecycle output', () => {
+  const output = `build completed\n${JSON.stringify([artifact], null, 2)}\n`;
+  assert.deepEqual(parseNpmPackArtifacts(output, '@buzzr/mcp'), [artifact]);
+});
+
+test('normalizes the npm 12 workspace-keyed response', () => {
+  const output = JSON.stringify({ '@buzzr/mcp': artifact }, null, 2);
+  assert.deepEqual(parseNpmPackArtifacts(output, '@buzzr/mcp'), [artifact]);
+});
+
+test('rejects a keyed response for a different workspace', () => {
+  const output = JSON.stringify({ '@buzzr/dfs-engine': artifact });
+  assert.throws(
+    () => parseNpmPackArtifacts(output, '@buzzr/mcp'),
+    /Expected npm pack output for @buzzr\/mcp/,
+  );
+});
+
+test('rejects an array response for a different workspace', () => {
+  const output = JSON.stringify([{ ...artifact, name: '@buzzr/dfs-engine' }]);
+  assert.throws(
+    () => parseNpmPackArtifacts(output, '@buzzr/mcp'),
+    /Packed the wrong workspace for @buzzr\/mcp/,
+  );
+});
+
+test('rejects multiple packed artifacts', () => {
+  const output = JSON.stringify([artifact, { ...artifact, name: '@buzzr/dfs-engine' }]);
+  assert.throws(
+    () => parseNpmPackArtifacts(output, '@buzzr/mcp'),
+    /Expected one packed artifact for @buzzr\/mcp/,
+  );
+});
+
+test('rejects output without a JSON result', () => {
+  assert.throws(
+    () => parseNpmPackArtifacts('npm lifecycle output only', '@buzzr/mcp'),
+    /Could not parse npm pack JSON output for @buzzr\/mcp/,
+  );
+});