fix(core): add missing root export to package.json

.changeset/easy-masks-post.md

@@ -0,0 +1,5 @@
+---
+"@langchain/core": patch
+---
+
+add root export to satisfy bundler requirements

langchain-core/.gitignore

@@ -1,3 +1,7 @@
+index.cjs
+index.js
+index.d.ts
+index.d.cts
 agents.cjs
 agents.js
 agents.d.ts

langchain-core/langchain.config.js

@@ -12,6 +12,7 @@ function abs(relativePath) {
 export const config = {
   internals: [/node\:/, /js-tiktoken/, /langsmith/, /zod\/v[34]/],
   entrypoints: {
+    index: "index",
     agents: "agents",
     caches: "caches/base",
     "callbacks/base": "callbacks/base",

langchain-core/package.json

@@ -89,6 +89,15 @@
     "vectorstores"
   ],
   "exports": {
+    ".": {
+      "types": {
+        "import": "./index.d.ts",
+        "require": "./index.d.cts",
+        "default": "./index.d.ts"
+      },
+      "import": "./index.js",
+      "require": "./index.cjs"
+    },
     "./agents": {
       "types": {
         "import": "./agents.d.ts",
@@ -651,6 +660,10 @@
   },
   "files": [
     "dist/",
+    "index.cjs",
+    "index.js",
+    "index.d.ts",
+    "index.d.cts",
     "agents.cjs",
     "agents.js",
     "agents.d.ts",

langchain-core/src/index.ts

@@ -0,0 +1,22 @@
+/**
+ * @langchain/core root entry point
+ *
+ * This file exists solely to satisfy bundler requirements for packages that use
+ * static manual chunks (e.g., Vite's manualChunks, Webpack's splitChunks).
+ *
+ * IMPORTANT: Do not import from this root entry point in your code.
+ * Instead, use specific subpath imports for better tree-shaking and performance:
+ *
+ * ❌ Don't do this:
+ * import { BaseMessage } from "@langchain/core";
+ *
+ * ✅ Do this instead:
+ * import { BaseMessage } from "@langchain/core/messages";
+ * import { BaseChatModel } from "@langchain/core/language_models/chat_models";
+ *
+ * This approach ensures optimal bundle size and follows the intended usage pattern
+ * of this package.
+ */
+
+// Empty export to make this a valid ES module
+export {};