diff --git a/tools/cli/installers/lib/modules/manager.js b/tools/cli/installers/lib/modules/manager.js
index 831b6e6f4..e079c831b 100644
--- a/tools/cli/installers/lib/modules/manager.js
+++ b/tools/cli/installers/lib/modules/manager.js
@@ -1299,8 +1299,8 @@ class ModuleManager {
       } else {
         const { pathToFileURL } = require('node:url');
         const imported = await import(pathToFileURL(installerPath).href);
-        // CJS module.exports lands on .default, ESM named exports are top-level
-        moduleInstaller = imported.default && typeof imported.default === 'object' ? imported.default : imported;
+        // CJS module.exports lands on .default; ESM default can be object, function, or class
+        moduleInstaller = imported.default == null ? imported : imported.default;
       }
 
       if (typeof moduleInstaller.install === 'function') {
diff --git a/tools/cli/lib/ui.js b/tools/cli/lib/ui.js
index 4beaf41ab..622f5a1e6 100644
--- a/tools/cli/lib/ui.js
+++ b/tools/cli/lib/ui.js
@@ -361,6 +361,9 @@ class UI {
           selectedModules.push(...customModuleResult.selectedCustomModules);
         }
 
+        // Filter out core - it's always installed via installCore flag
+        selectedModules = selectedModules.filter((m) => m !== 'core');
+
         // Get tool selection
         const toolSelection = await this.promptToolSelection(confirmedDirectory, options);
 
@@ -898,9 +901,10 @@ class UI {
   }
 
   /**
-   * Select all modules (core + official + community) using grouped multiselect
+   * Select all modules (official + community) using grouped multiselect.
+   * Core is shown as locked but filtered from the result since it's always installed separately.
    * @param {Set} installedModuleIds - Currently installed module IDs
-   * @returns {Array} Selected module codes
+   * @returns {Array} Selected module codes (excluding core)
    */
   async selectAllModules(installedModuleIds = new Set()) {
     const { ModuleManager } = require('../installers/lib/modules/manager');