fix(langgraph): set status for tool messages generated by ToolNode (#1519)

.changeset/loose-beers-sink.md

@@ -0,0 +1,5 @@
+---
+"@langchain/langgraph": patch
+---
+
+fix(langgraph): set status for tool messages generated by ToolNode

libs/langgraph/src/prebuilt/tool_node.ts

@@ -186,6 +186,7 @@ export class ToolNode<T = any> extends RunnableCallable<T, T> {
       }
 
       return new ToolMessage({
+        status: "success",
         name: tool.name,
         content: typeof output === "string" ? output : JSON.stringify(output),
         tool_call_id: call.id!,
@@ -202,6 +203,7 @@ export class ToolNode<T = any> extends RunnableCallable<T, T> {
       }
 
       return new ToolMessage({
+        status: "error",
         content: `Error: ${e.message}\n Please fix your mistakes.`,
         name: call.name,
         tool_call_id: call.id ?? "",

libs/langgraph/src/tests/prebuilt.test.ts

@@ -525,6 +525,7 @@ describe.each([["v1" as const], ["v2" as const]])(
           }),
           new _AnyIdToolMessage({
             name: "search_api",
+            status: "success",
             content: "result for foo",
             tool_call_id: "tool_abcd123",
           }),
@@ -1040,6 +1041,7 @@ describe.each([["v1" as const], ["v2" as const]])(
             ],
           }),
           new _AnyIdToolMessage({
+            status: "success",
             name: "search_api",
             content: "result for foo",
             tool_call_id: "tool_abcd123",
@@ -2589,6 +2591,24 @@ describe.each([["v1" as const], ["v2" as const]])(
         ],
       });
     });
+
+    it("should handle tool errors", async () => {
+      const toolNode = new ToolNode([new SearchAPI()]);
+      const res = await toolNode.invoke([
+        new AIMessage({
+          content: "",
+          tool_calls: [{ name: "badtool", args: {}, id: "testid" }],
+        }),
+      ]);
+
+      expect(res).toMatchObject([
+        {
+          status: "error",
+          content:
+            'Error: Tool "badtool" not found.\n Please fix your mistakes.',
+        },
+      ]);
+    });
   }
 );