diff --git a/files/__addonLocation__/package.json b/files/__addonLocation__/package.json
index 762892f..450cdf7 100644
--- a/files/__addonLocation__/package.json
+++ b/files/__addonLocation__/package.json
@@ -13,11 +13,8 @@
     "declarations",
     "dist"
   ],
-  "scripts": {<% if (typescript) { %>
-    "build": "concurrently '<%= packageManager %>:build:*'",
-    "build:js": "rollup --config",
-    "build:types": "glint --declaration",<% } else { %>
-    "build": "rollup --config",<% } %>
+  "scripts": {
+    "build": "rollup --config",
     "lint": "concurrently '<%= packageManager %>:lint:*(!fix)' --names 'lint:'",
     "lint:fix": "concurrently '<%= packageManager %>:lint:*:fix' --names 'fix:'",
     "lint:hbs": "ember-template-lint . --no-error-on-unmatched-pattern",
@@ -84,6 +81,8 @@
     "prettier-plugin-ember-template-tag": "^2.0.2",
     "rollup": "^4.16.4"<% if (!isExistingMonorepo) { %>,
     "rollup-plugin-copy": "^3.5.0"<% } %><% if (typescript) { %>,
+    "execa": "9.2.0",
+    "fix-bad-declaration-output": "1.1.4",
     "typescript": "^5.4.5"<% } %>
   },
   "publishConfig": {
diff --git a/files/__addonLocation__/rollup.config.mjs b/files/__addonLocation__/rollup.config.mjs
index 2a49ed1..8a895b0 100644
--- a/files/__addonLocation__/rollup.config.mjs
+++ b/files/__addonLocation__/rollup.config.mjs
@@ -1,6 +1,10 @@
 import { babel } from '@rollup/plugin-babel';
 <% if (!isExistingMonorepo) { %>import copy from 'rollup-plugin-copy';
 <% } %>import { Addon } from '@embroider/addon-dev/rollup';
+<% if (typescript) { %>
+import { $ } from "execa";
+import { fixBadDeclarationOutput } from "fix-bad-declaration-output";
+<% } %>
 
 const addon = new Addon({
   srcDir: 'src',
@@ -67,5 +71,37 @@ export default {
 <% filesToCopyFromRootToAddon.forEach((file) => { %>        { src: '<%= pathFromAddonToRoot %>/<%= file %>', dest: '.' },
 <% }); %>      ],
     }),
-<% } %>  ],
+<% } %>
+
+<% if (typescript) { %>
+    {
+      name: "Build Declarations",
+      closeBundle: async () => {
+        /**
+         * Generate the types (these include /// <reference types="ember-source/types"
+         * but our consumers may not be using those, or have a new enough ember-source that provides them.
+         */
+        console.log("Building types");
+        <% if (npm) { %>
+        await $({ stdio: 'inherit' })`npm exec glint -- --declaration`;
+        <% } else { %>
+        await $({ stdio: 'inherit' })`<%= packageManager %> glint --declaration`;
+        <% } %>
+
+        /**
+         * https://github.com/microsoft/TypeScript/issues/56571#
+         * README: https://github.com/NullVoxPopuli/fix-bad-declaration-output
+         */
+        console.log("Fixing types");
+        await fixBadDeclarationOutput("declarations/**/*.d.ts", [
+          // https://github.com/microsoft/TypeScript/issues/56571#issuecomment-1830436576
+          ["TypeScript#56571", { types: "all" }],
+          // https://github.com/typed-ember/glint/issues/628
+          "Glint#628",
+        ]);
+        console.log("⚠️ Dangerously (but neededly) fixed bad declaration output from typescript");
+      },
+    },
+<% } %>
+  ],
 };