diff --git a/cmd/workers-assets-gen/assets/common/shim.mjs b/cmd/workers-assets-gen/assets/common/shim.mjs
index 2d93a85f..52ec993a 100644
--- a/cmd/workers-assets-gen/assets/common/shim.mjs
+++ b/cmd/workers-assets-gen/assets/common/shim.mjs
@@ -1,5 +1,5 @@
 import "./wasm_exec.js";
-import { connect } from 'cloudflare:sockets';
+import { createRuntimeContext } from "./runtime.mjs";
 
 let mod;
 
@@ -8,12 +8,12 @@ globalThis.tryCatch = (fn) => {
     return {
       result: fn(),
     };
-  } catch(e) {
+  } catch (e) {
     return {
       error: e,
     };
   }
-}
+};
 
 export function init(m) {
   mod = m;
@@ -29,31 +29,24 @@ async function run(ctx) {
   const instance = new WebAssembly.Instance(mod, {
     ...go.importObject,
     workers: {
-      ready: () => { ready() }
+      ready: () => {
+        ready();
+      },
     },
   });
   go.run(instance, ctx);
   await readyPromise;
 }
 
-function createRuntimeContext(env, ctx, binding) {
-  return {
-    env,
-    ctx,
-    connect,
-    binding,
-  };
-}
-
 export async function fetch(req, env, ctx) {
   const binding = {};
-  await run(createRuntimeContext(env, ctx, binding));
+  await run(createRuntimeContext({ env, ctx, binding }));
   return binding.handleRequest(req);
 }
 
 export async function scheduled(event, env, ctx) {
   const binding = {};
-  await run(createRuntimeContext(env, ctx, binding));
+  await run(createRuntimeContext({ env, ctx, binding }));
   return binding.runScheduler(event);
 }
 
@@ -61,12 +54,12 @@ export async function scheduled(event, env, ctx) {
 export async function onRequest(ctx) {
   const binding = {};
   const { request, env } = ctx;
-  await run(createRuntimeContext(env, ctx, binding));
+  await run(createRuntimeContext({ env, ctx, binding }));
   return binding.handleRequest(request);
 }
 
 export async function queue(batch, env, ctx) {
   const binding = {};
-  await run(createRuntimeContext(env, ctx, binding));
+  await run(createRuntimeContext({ env, ctx, binding }));
   return binding.handleQueueMessageBatch(batch);
 }
diff --git a/cmd/workers-assets-gen/assets/runtime/cloudflare.mjs b/cmd/workers-assets-gen/assets/runtime/cloudflare.mjs
new file mode 100644
index 00000000..baa446d2
--- /dev/null
+++ b/cmd/workers-assets-gen/assets/runtime/cloudflare.mjs
@@ -0,0 +1,10 @@
+import { connect } from "cloudflare:sockets";
+
+export function createRuntimeContext({ env, ctx, binding }) {
+  return {
+    env,
+    ctx,
+    connect,
+    binding,
+  };
+}
diff --git a/cmd/workers-assets-gen/main.go b/cmd/workers-assets-gen/main.go
index 7ce13245..5f082065 100644
--- a/cmd/workers-assets-gen/main.go
+++ b/cmd/workers-assets-gen/main.go
@@ -16,13 +16,18 @@ var assets embed.FS
 const (
 	assetDirPath        = "assets"
 	commonDirPath       = "assets/common"
+	runtimeDirPath      = "assets/runtime"
 	defaultBuildDirPath = "build"
 )
 
 func main() {
-	var mode string
-	var buildDirPath string
+	var (
+		mode         string
+		runtime      string
+		buildDirPath string
+	)
 	flag.StringVar(&mode, "mode", string(ModeTinygo), `build mode: tinygo or go`)
+	flag.StringVar(&runtime, "runtime", string(RuntimeCloudflare), `runtime: cloudflare`)
 	flag.StringVar(&buildDirPath, "o", defaultBuildDirPath, `output dir path: defaults to "build"`)
 	flag.Parse()
 	if !Mode(mode).IsValid() {
@@ -30,13 +35,18 @@ func main() {
 		os.Exit(1)
 		return
 	}
-	if err := runMain(Mode(mode), buildDirPath); err != nil {
+	if !Runtime(runtime).IsValid() {
+		flag.PrintDefaults()
+		os.Exit(1)
+		return
+	}
+	if err := runMain(Mode(mode), Runtime(runtime), buildDirPath); err != nil {
 		fmt.Fprintf(os.Stderr, "err: %v", err)
 		os.Exit(1)
 	}
 }
 
-func runMain(mode Mode, buildDirPath string) error {
+func runMain(mode Mode, runtime Runtime, buildDirPath string) error {
 	if err := os.RemoveAll(buildDirPath); err != nil {
 		return err
 	}
@@ -46,6 +56,9 @@ func runMain(mode Mode, buildDirPath string) error {
 	if err := copyWasmExecJS(mode, buildDirPath); err != nil {
 		return err
 	}
+	if err := copyRuntimeAssets(runtime, buildDirPath); err != nil {
+		return err
+	}
 	if err := copyCommonAssets(buildDirPath); err != nil {
 		return err
 	}
@@ -70,6 +83,15 @@ func copyWasmExecJS(mode Mode, buildDirPath string) error {
 	return nil
 }
 
+func copyRuntimeAssets(runtime Runtime, buildDirPath string) error {
+	destPath := path.Join(buildDirPath, "runtime.mjs")
+	originPath := path.Join(runtimeDirPath, runtime.AssetFileName())
+	if err := copyFile(destPath, originPath); err != nil {
+		return err
+	}
+	return nil
+}
+
 func copyCommonAssets(buildDirPath string) error {
 	entries, err := assets.ReadDir(commonDirPath)
 	if err != nil {
@@ -90,9 +112,6 @@ func copyFile(destPath, originPath string) error {
 	if err != nil {
 		return err
 	}
-	if err != nil {
-		return err
-	}
 	dest, err := os.Create(destPath)
 	if err != nil {
 		return err
@@ -102,8 +121,5 @@ func copyFile(destPath, originPath string) error {
 	if err != nil {
 		return err
 	}
-	if err != nil {
-		return err
-	}
 	return nil
 }
diff --git a/cmd/workers-assets-gen/runtime.go b/cmd/workers-assets-gen/runtime.go
new file mode 100644
index 00000000..aa19ab20
--- /dev/null
+++ b/cmd/workers-assets-gen/runtime.go
@@ -0,0 +1,19 @@
+package main
+
+type Runtime string
+
+const (
+	RuntimeCloudflare Runtime = "cloudflare"
+)
+
+func (r Runtime) IsValid() bool {
+	switch r {
+	case RuntimeCloudflare:
+		return true
+	}
+	return false
+}
+
+func (r Runtime) AssetFileName() string {
+	return string(r) + ".mjs"
+}