start adding dummy nodes

agent/nodes/tool.ts

@@ -1,8 +1,25 @@
-import type { ToolCall } from "@langchain/core/messages/tool";
-import { task } from "@langchain/langgraph";
+import { AIMessage, ToolMessage } from "@langchain/core/messages";
+import { GraphNode } from "@langchain/langgraph";
+import { MessagesState } from "../state";
 import { arithmeticToolsByName } from "../tools/arithmetic";
 
-export const toolNode = task({ name: "callTool" }, async (toolCall: ToolCall) => {
-  const tool = arithmeticToolsByName[toolCall.name];
-  return tool.invoke(toolCall);
-});
+export const toolNode: GraphNode<typeof MessagesState> = async (state) => {
+  const lastMessage = state.messages.at(-1);
+
+  //STARTTEMP
+  return {messages: [new AIMessage("yeman")]}
+  //ENDTEMP
+  
+  if (lastMessage == null || !AIMessage.isInstance(lastMessage)) {
+    return { messages: [] };
+  }
+
+  const result: ToolMessage[] = [];
+  for (const toolCall of lastMessage.tool_calls ?? []) {
+    const tool = arithmeticToolsByName[toolCall.name];
+    const observation = await tool.invoke(toolCall);
+    result.push(observation);
+  }
+
+  return { messages: result };
+};