diff --git a/scripts/grok-install.js b/scripts/grok-install.js
index 09663dce4..c6fe3904c 100644
--- a/scripts/grok-install.js
+++ b/scripts/grok-install.js
@@ -19,13 +19,21 @@ function canonicalArgs(argv = process.argv.slice(2)) {
   for (let index = 0; index < argv.length; index += 1) {
     const argument = argv[index];
     if (argument === '--target') {
+      const value = argv[index + 1];
+      if (!value || value.startsWith('-')) {
+        throw new Error('Missing value for --target');
+      }
       index += 1;
       continue;
     }
     args.push(argument);
     if (SELECTION_FLAGS.has(argument)) hasSelection = true;
     if (VALUE_FLAGS.has(argument)) {
-      if (index + 1 < argv.length) args.push(argv[index + 1]);
+      const value = argv[index + 1];
+      if (!value || value.startsWith('-')) {
+        throw new Error(`Missing value for ${argument}`);
+      }
+      args.push(value);
       index += 1;
     } else if (!argument.startsWith('-')) {
       hasSelection = true;
diff --git a/tests/lib/grok-canonical-install.test.js b/tests/lib/grok-canonical-install.test.js
index 55895feb2..ee85f2028 100644
--- a/tests/lib/grok-canonical-install.test.js
+++ b/tests/lib/grok-canonical-install.test.js
@@ -247,11 +247,13 @@ function runTests() {
     const destination = path.join(parent, 'snapshot');
     const calls = [];
     try {
+      const archive = Buffer.from('archive');
       copyGitArchive('/source', 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb', destination, (...args) => {
         calls.push(args);
-        return Buffer.alloc(0);
+        return archive;
       });
       assert.deepStrictEqual(calls[1][1], ['-x', '-f', '-', '-C', destination]);
+      assert.deepStrictEqual(calls[1][2].input, archive);
     } finally {
       fs.rmSync(parent, { recursive: true, force: true });
     }
diff --git a/tests/scripts/install-apply.test.js b/tests/scripts/install-apply.test.js
index db541c91a..2d0a3264e 100644
--- a/tests/scripts/install-apply.test.js
+++ b/tests/scripts/install-apply.test.js
@@ -165,6 +165,11 @@ function runTests() {
     );
   })) passed++; else failed++;
 
+  if (test('Grok alias rejects option-prefixed values for value flags', () => {
+    assert.throws(() => canonicalArgs(['--target', '--dry-run']), /Missing value for --target/);
+    assert.throws(() => canonicalArgs(['--consent-mcp', '--dry-run']), /Missing value for --consent-mcp/);
+  })) passed++; else failed++;
+
   if (test('plans Grok through the canonical request with a local pinned fixture', () => {
     const homeDir = createTempDir('install-apply-grok-home-');
     const fixtureRoot = createTempDir('install-apply-grok-source-');
@@ -174,11 +179,17 @@ function runTests() {
       const sourceSha = execFileSync('git', ['rev-parse', 'HEAD'], { cwd: sourceRoot, encoding: 'utf8' }).trim();
       const marketplacePath = path.join(sourceRoot, '.grok-plugin', 'marketplace.json');
       const marketplace = readJson(marketplacePath);
-      marketplace.plugins[0] = {
-        ...marketplace.plugins[0],
-        source: { source: 'url', url: sourceRoot, sha: sourceSha },
+      const updatedMarketplace = {
+        ...marketplace,
+        plugins: [
+          {
+            ...marketplace.plugins[0],
+            source: { source: 'url', url: sourceRoot, sha: sourceSha },
+          },
+          ...marketplace.plugins.slice(1),
+        ],
       };
-      fs.writeFileSync(marketplacePath, `${JSON.stringify(marketplace, null, 2)}\n`);
+      fs.writeFileSync(marketplacePath, `${JSON.stringify(updatedMarketplace, null, 2)}\n`);
 
       const result = run(
         ['--target', 'grok', '--profile', 'minimal', '--dry-run', '--json'],