diff --git a/.changeset/chilled-boats-thank.md b/.changeset/chilled-boats-thank.md
new file mode 100644
index 000000000..f31c2cb01
--- /dev/null
+++ b/.changeset/chilled-boats-thank.md
@@ -0,0 +1,7 @@
+---
+"@assistant-ui/react-markdown": patch
+"@assistant-ui/react-trieve": patch
+"@assistant-ui/react": patch
+---
+
+fix: cjs builds
diff --git a/packages/tsbuildutils/src/index.ts b/packages/tsbuildutils/src/index.ts
index dd9b1baff..b786754cf 100644
--- a/packages/tsbuildutils/src/index.ts
+++ b/packages/tsbuildutils/src/index.ts
@@ -45,7 +45,11 @@ const transpileTypescript = async () => {
     splitting: false,
     silent: true,
 
-    esbuildPlugins: [esbuildPluginFilePathExtensions()],
+    esbuildPlugins: [
+      esbuildPluginFilePathExtensions({
+        cjsExtension: "js",
+      }),
+    ],
   });
 };