diff --git a/files/__addonLocation__/.eslintrc.cjs b/files/__addonLocation__/.eslintrc.cjs
index 5384483..a472414 100644
--- a/files/__addonLocation__/.eslintrc.cjs
+++ b/files/__addonLocation__/.eslintrc.cjs
@@ -32,6 +32,20 @@ module.exports = {
         // Add any custom rules here
       },
     },
+    // require relative imports use full extensions
+    {
+      files: ['src/**/*.{js,ts,gjs,gts}'],
+      rules: {
+        'import/extensions': ['error', 'always', { ignorePackages: true }],
+      },
+    },
+<% } else { %>    // require relative imports use full extensions
+    {
+      files: ['src/**/*.{js,gjs}'],
+      rules: {
+        'import/extensions': ['error', 'always', { ignorePackages: true }],
+      },
+    },
 <% } %>    // node files
     {
       files: [
diff --git a/files/__addonLocation__/package.json b/files/__addonLocation__/package.json
index a81736c..84f9c8e 100644
--- a/files/__addonLocation__/package.json
+++ b/files/__addonLocation__/package.json
@@ -76,6 +76,7 @@
     "eslint": "^8.56.0",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-ember": "^11.12.0",
+    "eslint-plugin-import": "^2.29.1",
     "eslint-plugin-n": "^16.4.0",
     "eslint-plugin-prettier": "^5.0.1",
     "prettier": "^3.1.1",