diff --git a/index.js b/index.js
index 738a975..b47adc5 100644
--- a/index.js
+++ b/index.js
@@ -69,15 +69,36 @@ export default function serviceWorker(config) {
         registerSW();`
 
     let output = 'static';
+    const __dirname = path.resolve(path.dirname('.'));
 
     return {
         'name': 'astro-sw',
         'hooks': {
-            'astro:config:setup': ({ injectScript, config, command }) => {
+            'astro:config:setup': async ({ injectScript, config, command, logger }) => {
                 output = config.output;
                 if (command === 'build') {
                     injectScript('page', registrationScript);
                 }
+
+                const injectedTypeDefinitions = `
+/***
+ * @ayco/astro-sw injected variables
+ */
+declare const __assets: string;
+declare const __version: string;
+declare const __prefix: string;
+                `
+
+                const envTs = path.join(__dirname, 'src/env.d.ts');
+                try {
+                    await writeFile(
+                        envTs,
+                        injectedTypeDefinitions,
+                        { flag: 'a+' }
+                    );
+                } catch (err) {
+                    logger.error(err.toString())
+                }
             },
             'astro:build:ssr': ({ manifest }) => {
                 const files = manifest.routes.map(route => route.file.replaceAll('/', ''));
@@ -89,7 +110,6 @@ export default function serviceWorker(config) {
             },
             'astro:build:done': async ({ dir, routes, pages, logger }) => {
                 const outfile = fileURLToPath(new URL('./sw.js', dir));
-                const __dirname = path.resolve(path.dirname('.'));
                 const swPath = path.join(__dirname, serviceWorkerPath ?? '');
                 let originalScript;
 
diff --git a/src/example_sw.ts b/src/example_sw.ts
index 744d419..70fe866 100644
--- a/src/example_sw.ts
+++ b/src/example_sw.ts
@@ -1,11 +1,11 @@
 import { log } from "./utils";
 
 /**
- * Note: @ayco/astro-sw integration injects variables `__astro_sw_cache_prefix__`, `__astro_sw_version__`, & `__astro_sw_assets__`
+ * Note: @ayco/astro-sw integration injects variables `__prefix`, `__version`, & `__assets`
  * -- find usage in package readme; `astro.config.mjs` integrations
  * @see https://ayco.io/n/@ayco/astro-sw
  */
-const cacheName = `${__astro_sw_cache_prefix__ ?? 'app'}-v${__astro_sw_version__ ?? '000'}`
+const cacheName = `${__prefix ?? 'app'}-v${__version ?? '000'}`
 const addResourcesToCache = async (resources) => {
     const cache = await caches.open(cacheName);
     console.log('adding resources to cache...', resources)
@@ -80,7 +80,7 @@ self.addEventListener('install', (event) => {
     event.waitUntil(
         addResourcesToCache([
             './',
-            ...(__astro_sw_assets__ ?? [])
+            ...(__assets ?? [])
         ])
     );
 });