diff --git a/packages/utility-belt/index.d.ts b/packages/utility-belt/index.d.ts
new file mode 100644
index 0000000..2271bf0
--- /dev/null
+++ b/packages/utility-belt/index.d.ts
@@ -0,0 +1,7 @@
+export type RequireOnly<T, Keys extends keyof T = keyof T> = Partial<T> &
+  Required<Pick<T, Keys>>;
+export declare const isError: (error: unknown) => error is Error;
+export declare const getErrorMessage: (
+  error: unknown,
+  defaultMessage: string,
+) => string;
diff --git a/packages/utility-belt/index.js b/packages/utility-belt/index.js
new file mode 100644
index 0000000..07f50f6
--- /dev/null
+++ b/packages/utility-belt/index.js
@@ -0,0 +1,16 @@
+/**
+ *
+ * @param {unknown} error The error object to check.
+ * @returns {error is Error}
+ */
+export const isError = (error) => error instanceof Error;
+
+/**
+ * Get the error message from an error object or return a default message.
+ * @param {unknown} error The error object to check.
+ * @param {string} defaultMessage The default message to return if the error is not an instance of Error.
+ * @returns {string} The error message or the default message.
+ */
+export const getErrorMessage = (error, defaultMessage) => {
+  return isError(error) ? error.message : defaultMessage;
+};
diff --git a/packages/utility-belt/package.json b/packages/utility-belt/package.json
new file mode 100644
index 0000000..fe4971b
--- /dev/null
+++ b/packages/utility-belt/package.json
@@ -0,0 +1,23 @@
+{
+  "name": "utility-belt",
+  "version": "1.0.0",
+  "description": "Some little utilities",
+  "main": "index.js",
+  "type": "module",
+  "scripts": {
+    "types": "tsc --emitDeclarationOnly --allowJs --declaration --skipLibCheck index.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/stevekinney/testing-javascript.git"
+  },
+  "author": "Steve Kinney <hello@stevekinney.net>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/stevekinney/testing-javascript/issues"
+  },
+  "homepage": "https://github.com/stevekinney/testing-javascript#readme",
+  "devDependencies": {
+    "typescript": "^5.6.2"
+  }
+}
diff --git a/types.d.ts b/types.d.ts
index 11f02fe..eae476b 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -1 +1,11 @@
 /// <reference types="vite/client" />
+
+declare module '*.html' {
+  const value: string;
+  export default value;
+}
+
+declare module '*.html?raw' {
+  const value: string;
+  export default value;
+}