diff --git a/langgraph/src/graph/messages_state.ts b/langgraph/src/graph/messages_annotation.ts
similarity index 85%
rename from langgraph/src/graph/messages_state.ts
rename to langgraph/src/graph/messages_annotation.ts
index 5c91b7c8..9f299365 100644
--- a/langgraph/src/graph/messages_state.ts
+++ b/langgraph/src/graph/messages_annotation.ts
@@ -4,7 +4,7 @@ import { BaseMessage } from "@langchain/core/messages";
 import { Annotation } from "./annotation.js";
 import { messagesStateReducer } from "./message.js";
 
-export const MessagesState = Annotation.Root({
+export const MessagesAnnotation = Annotation.Root({
   messages: Annotation<BaseMessage[]>({
     reducer: messagesStateReducer,
     default: () => [],
diff --git a/langgraph/src/index.ts b/langgraph/src/index.ts
index f57f4e4f..5a2c0920 100644
--- a/langgraph/src/index.ts
+++ b/langgraph/src/index.ts
@@ -6,4 +6,4 @@ import { initializeAsyncLocalStorageSingleton } from "./setup/async_local_storag
 initializeAsyncLocalStorageSingleton();
 
 export * from "./web.js";
-export { MessagesState } from "./graph/messages_state.js";
+export { MessagesAnnotation } from "./graph/messages_annotation.js";
diff --git a/langgraph/src/prebuilt/react_agent_executor.ts b/langgraph/src/prebuilt/react_agent_executor.ts
index 27a8e952..c28e3ce3 100644
--- a/langgraph/src/prebuilt/react_agent_executor.ts
+++ b/langgraph/src/prebuilt/react_agent_executor.ts
@@ -21,7 +21,7 @@ import {
 import { ChatPromptTemplate } from "@langchain/core/prompts";
 import { BaseCheckpointSaver } from "../checkpoint/base.js";
 import { END, START, StateGraph } from "../graph/index.js";
-import { MessagesState } from "../graph/messages_state.js";
+import { MessagesAnnotation } from "../graph/messages_annotation.js";
 import { CompiledStateGraph, StateGraphArgs } from "../graph/state.js";
 import { All } from "../pregel/types.js";
 import { ToolNode } from "./tool_node.js";
@@ -40,7 +40,7 @@ export type N = typeof START | "agent" | "tools";
 export type CreateReactAgentParams = {
   llm: BaseChatModel;
   tools:
-    | ToolNode<typeof MessagesState.State>
+    | ToolNode<typeof MessagesAnnotation.State>
     | (StructuredToolInterface | RunnableToolLike)[];
   messageModifier?:
     | SystemMessage
diff --git a/langgraph/src/prebuilt/tool_node.ts b/langgraph/src/prebuilt/tool_node.ts
index 5ff3fdbb..9cb6bf7e 100644
--- a/langgraph/src/prebuilt/tool_node.ts
+++ b/langgraph/src/prebuilt/tool_node.ts
@@ -8,7 +8,7 @@ import { RunnableConfig, RunnableToolLike } from "@langchain/core/runnables";
 import { StructuredToolInterface } from "@langchain/core/tools";
 import { RunnableCallable } from "../utils.js";
 import { END } from "../graph/graph.js";
-import { MessagesState } from "../graph/messages_state.js";
+import { MessagesAnnotation } from "../graph/messages_annotation.js";
 
 export type ToolNodeOptions = {
   name?: string;
@@ -17,7 +17,7 @@ export type ToolNodeOptions = {
 };
 
 export class ToolNode<
-  T extends BaseMessage[] | typeof MessagesState.State
+  T extends BaseMessage[] | typeof MessagesAnnotation.State
 > extends RunnableCallable<T, T> {
   /**
   A node that runs the tools requested in the last AIMessage. It can be used
@@ -41,9 +41,9 @@ export class ToolNode<
   }
 
   private async run(
-    input: BaseMessage[] | typeof MessagesState.State,
+    input: BaseMessage[] | typeof MessagesAnnotation.State,
     config: RunnableConfig
-  ): Promise<BaseMessage[] | typeof MessagesState.State> {
+  ): Promise<BaseMessage[] | typeof MessagesAnnotation.State> {
     const message = Array.isArray(input)
       ? input[input.length - 1]
       : input.messages[input.messages.length - 1];
@@ -92,7 +92,7 @@ export class ToolNode<
 }
 
 export function toolsCondition(
-  state: BaseMessage[] | typeof MessagesState.State
+  state: BaseMessage[] | typeof MessagesAnnotation.State
 ): "tools" | typeof END {
   const message = Array.isArray(state)
     ? state[state.length - 1]