diff --git a/scripts/lib/install/request.js b/scripts/lib/install/request.js
index 28fab4acb..9dfbed7e2 100644
--- a/scripts/lib/install/request.js
+++ b/scripts/lib/install/request.js
@@ -4,6 +4,7 @@ const { validateInstallModuleIds, LOCALE_ALIAS_TO_COMPONENT_ID, listSupportedLoc
 const { resolveHookConsentFlags } = require('./hook-consent');
 
 const LEGACY_INSTALL_TARGETS = ['claude', 'claude-project', 'cursor', 'antigravity'];
+const LOCALE_COMPONENT_IDS = new Set(Object.values(LOCALE_ALIAS_TO_COMPONENT_ID));
 
 function dedupeStrings(values) {
   return [...new Set((Array.isArray(values) ? values : []).map(value => String(value).trim()).filter(Boolean))];
@@ -103,6 +104,7 @@ function normalizeInstallRequest(options = {}) {
     : null;
   const profileId = options.profileId || config?.profileId || null;
   const target = options.target || config?.target || 'claude';
+  const supportsLocale = target === 'claude' || target === 'claude-project';
   const moduleIds = validateInstallModuleIds(
     dedupeStrings([...(config?.moduleIds || []), ...(options.moduleIds || [])])
   );
@@ -113,7 +115,7 @@ function normalizeInstallRequest(options = {}) {
       `Unsupported locale: "${locale}". Supported locales: ${listSupportedLocales().join(', ')}`
     );
   }
-  if (locale && target !== 'claude' && target !== 'claude-project') {
+  if (locale && !supportsLocale) {
     throw new Error('--locale can only be used with --target claude or --target claude-project');
   }
   const requestedIncludeComponentIds = dedupeStrings([
@@ -139,7 +141,8 @@ function normalizeInstallRequest(options = {}) {
   const hasManifestBaseSelection = Boolean(profileId) || moduleIds.length > 0 || includeComponentIds.length > 0;
   const hasNonLocaleManifestSelection = Boolean(profileId)
     || moduleIds.length > 0
-    || requestedIncludeComponentIds.length > 0
+    // Install-state persists --locale as a component; auto-update replays it via --with.
+    || requestedIncludeComponentIds.some(id => !supportsLocale || !LOCALE_COMPONENT_IDS.has(id))
     || excludeComponentIds.length > 0;
   const usingManifestMode = hasManifestBaseSelection || excludeComponentIds.length > 0;
 
diff --git a/tests/lib/install-request.test.js b/tests/lib/install-request.test.js
index 9e580918c..276591f68 100644
--- a/tests/lib/install-request.test.js
+++ b/tests/lib/install-request.test.js
@@ -143,6 +143,60 @@ function runTests() {
     assert.deepStrictEqual(request.includeComponentIds, ['locale:ja']);
   })) passed++; else failed++;
 
+  if (test('accepts canonical locale components with legacy languages on Claude targets', () => {
+    for (const target of ['claude', 'claude-project']) {
+      const request = normalizeInstallRequest(parseInstallArgs([
+        'node', 'install-apply.js', '--target', target,
+        '--with', 'locale:zh-cn', '--with', 'locale:ja',
+        'typescript', '--no-hooks',
+      ]));
+      assert.strictEqual(request.mode, 'legacy-compat');
+      assert.deepStrictEqual(request.includeComponentIds, ['locale:zh-cn', 'locale:ja']);
+      assert.deepStrictEqual(request.legacyLanguages, ['typescript']);
+      assert.strictEqual(request.hookConsent, 'declined');
+    }
+  })) passed++; else failed++;
+
+  if (test('accepts config-backed locale components with legacy languages', () => {
+    const request = normalizeInstallRequest({
+      languages: ['typescript'],
+      config: { target: 'claude', includeComponentIds: ['locale:zh-cn'] },
+    });
+    assert.strictEqual(request.mode, 'legacy-compat');
+    assert.deepStrictEqual(request.includeComponentIds, ['locale:zh-cn']);
+  })) passed++; else failed++;
+
+  if (test('keeps non-locale manifest selections incompatible with legacy languages', () => {
+    const invalidSelections = [
+      { profileId: 'core' },
+      { moduleIds: ['rules-core'] },
+      { includeComponentIds: ['locale:zh-cn', 'skill:tdd-workflow'] },
+      { includeComponentIds: ['locale:fr'] },
+      { includeComponentIds: ['locale:zh-CN'] },
+      { excludeComponentIds: ['skill:tdd-workflow'] },
+      { config: { includeComponentIds: ['skill:tdd-workflow'] } },
+      { target: 'cursor' },
+      { target: 'antigravity' },
+    ];
+    for (const selection of invalidSelections) {
+      assert.throws(() => normalizeInstallRequest({
+        target: 'claude', languages: ['typescript'],
+        includeComponentIds: ['locale:zh-cn'], ...selection,
+      }), /cannot be combined/, JSON.stringify(selection));
+    }
+  })) passed++; else failed++;
+
+  if (test('locale components without legacy languages retain manifest mode', () => {
+    for (const profileId of [null, 'core']) {
+      const request = normalizeInstallRequest({
+        target: 'claude', profileId, includeComponentIds: ['locale:zh-cn'],
+      });
+      assert.strictEqual(request.mode, 'manifest');
+      assert.strictEqual(request.profileId, profileId);
+      assert.deepStrictEqual(request.includeComponentIds, ['locale:zh-cn']);
+    }
+  })) passed++; else failed++;
+
   if (test('rejects unsupported locale codes', () => {
     assert.throws(
       () => normalizeInstallRequest({
diff --git a/tests/scripts/auto-update.test.js b/tests/scripts/auto-update.test.js
index 9533fd67b..98d678902 100644
--- a/tests/scripts/auto-update.test.js
+++ b/tests/scripts/auto-update.test.js
@@ -6,6 +6,9 @@ const assert = require('assert');
 const fs = require('fs');
 const os = require('os');
 const path = require('path');
+const { execFileSync } = require('child_process');
+const { LOCALE_ALIAS_TO_COMPONENT_ID } = require('../../scripts/lib/install-manifests');
+const { normalizeInstallRequest, parseInstallArgs } = require('../../scripts/lib/install/request');
 
 const {
   parseArgs,
@@ -157,6 +160,76 @@ function runTests() {
     ]);
   })) passed += 1; else failed += 1;
 
+  if (test('replays every locale alias with legacy languages and hook consent', () => {
+    for (const target of ['claude', 'claude-project']) {
+      for (const [alias, componentId] of Object.entries(LOCALE_ALIAS_TO_COMPONENT_ID)) {
+        const original = normalizeInstallRequest(parseInstallArgs([
+          'node', 'install-apply.js', '--target', target,
+          '--locale', alias, 'typescript', 'python', '--no-hooks',
+        ]));
+        const record = makeRecord({
+          repoRoot: '/tmp/ecc', homeDir: '/tmp/home', projectRoot: '/tmp/project',
+          adapter: { id: target, target, kind: target === 'claude' ? 'home' : 'project' },
+          request: {
+            profile: original.profileId, modules: original.moduleIds,
+            includeComponents: original.includeComponentIds,
+            excludeComponents: original.excludeComponentIds,
+            legacyLanguages: original.legacyLanguages,
+            legacyMode: true, hookConsent: original.hookConsent,
+          },
+          resolution: { selectedModules: [], skippedModules: [] }, operations: [],
+        });
+        const replay = normalizeInstallRequest(parseInstallArgs([
+          'node', 'install-apply.js', ...buildInstallApplyArgs(record),
+        ]));
+        assert.deepStrictEqual(replay, original, `${target}: ${alias} -> ${componentId}`);
+      }
+    }
+  })) passed += 1; else failed += 1;
+
+  for (const target of ['claude', 'claude-project']) {
+    if (test(`end-to-end: auto-update plans a recorded ${target} locale and language install`, () => {
+      const fixture = createTempDir('auto-update-locale-');
+      const homeDir = path.join(fixture, 'home');
+      const projectRoot = path.join(fixture, 'project');
+      const repoRoot = path.resolve(__dirname, '..', '..');
+      const env = { ...process.env, HOME: homeDir, USERPROFILE: homeDir, ECC_DRY_RUN: '0' };
+      fs.mkdirSync(homeDir);
+      fs.mkdirSync(projectRoot);
+      try {
+        const installed = JSON.parse(execFileSync(process.execPath, [
+          path.join(repoRoot, 'scripts', 'install-apply.js'),
+          '--target', target, '--locale', 'zh', 'typescript', '--no-hooks', '--json',
+        ], { cwd: projectRoot, env, encoding: 'utf8', maxBuffer: 16 * 1024 * 1024 }));
+        assert.strictEqual(installed.result.applied, true);
+        const statePath = installed.result.installStatePath;
+        const stateBefore = fs.readFileSync(statePath, 'utf8');
+        const state = JSON.parse(stateBefore);
+        assert.deepStrictEqual(state.request.includeComponents, ['locale:zh-cn']);
+        assert.deepStrictEqual(state.request.legacyLanguages, ['typescript']);
+
+        const updated = JSON.parse(execFileSync(process.execPath, [
+          path.join(repoRoot, 'scripts', 'auto-update.js'), '--target', target,
+          '--repo-root', repoRoot, '--dry-run', '--json',
+        ], { cwd: projectRoot, env, encoding: 'utf8', maxBuffer: 16 * 1024 * 1024 }));
+        assert.strictEqual(updated.summary.errorCount, 0);
+        assert.strictEqual(updated.summary.checkedCount, 1);
+        assert.strictEqual(updated.results[0].status, 'planned');
+        const plan = updated.results[0].payload.plan;
+        assert.strictEqual(plan.mode, 'legacy-compat');
+        assert.deepStrictEqual(plan.legacyLanguages, ['typescript']);
+        assert.deepStrictEqual(plan.includedComponentIds, ['locale:zh-cn']);
+        assert.ok(plan.selectedModuleIds.includes('docs-zh-cn'));
+        assert.ok(plan.selectedModuleIds.includes('framework-language'));
+        assert.ok(!plan.selectedModuleIds.includes('hooks-runtime'));
+        assert.strictEqual(plan.statePreview.request.hookConsent, 'declined');
+        assert.strictEqual(fs.readFileSync(statePath, 'utf8'), stateBefore);
+      } finally {
+        cleanup(fixture);
+      }
+    })) passed += 1; else failed += 1;
+  }
+
   if (test('buildInstallApplyArgs reconstructs manifest installs', () => {
     const record = {
       adapter: { target: 'cursor', kind: 'project' },