fix(anthropic): Pass back full Anthropic content for stream events (#…

…6997)

libs/langchain-anthropic/src/chat_models.ts

@@ -818,7 +818,7 @@ export class ChatAnthropicMessages<
 
       // Extract the text content token for text field and runManager.
       const token = extractToken(chunk);
-      yield new ChatGenerationChunk({
+      const generationChunk = new ChatGenerationChunk({
         message: new AIMessageChunk({
           // Just yield chunk as it is and tool_use will be concat by BaseChatModel._generateUncached().
           content: chunk.content,
@@ -830,10 +830,16 @@ export class ChatAnthropicMessages<
         }),
         text: token ?? "",
       });
-
-      if (token) {
-        await runManager?.handleLLMNewToken(token);
-      }
+      yield generationChunk;
+
+      await runManager?.handleLLMNewToken(
+        token ?? "",
+        undefined,
+        undefined,
+        undefined,
+        undefined,
+        { chunk: generationChunk }
+      );
     }
   }
 

libs/langchain-anthropic/src/tests/chat_models-tools.int.test.ts

@@ -11,6 +11,7 @@ import { StructuredTool, tool } from "@langchain/core/tools";
 import { concat } from "@langchain/core/utils/stream";
 import { z } from "zod";
 import { zodToJsonSchema } from "zod-to-json-schema";
+import { RunnableLambda } from "@langchain/core/runnables";
 import { ChatAnthropic } from "../chat_models.js";
 import { AnthropicToolResponse } from "../types.js";
 
@@ -202,6 +203,73 @@ test("Can bind & stream AnthropicTools", async () => {
   expect(args.location).toBeTruthy();
 });
 
+test("stream events with no tool calls has string message content", async () => {
+  const wrapper = RunnableLambda.from(async (_, config) => {
+    const res = await model.invoke(
+      "What is the weather in London today?",
+      config
+    );
+    return res;
+  });
+  const eventStream = await wrapper.streamEvents(
+    "What is the weather in London today?",
+    {
+      version: "v2",
+    }
+  );
+
+  const chatModelStreamEvents = [];
+  for await (const event of eventStream) {
+    if (event.event === "on_chat_model_stream") {
+      chatModelStreamEvents.push(event);
+    }
+  }
+  expect(chatModelStreamEvents.length).toBeGreaterThan(0);
+  expect(
+    chatModelStreamEvents.every(
+      (event) => typeof event.data.chunk.content === "string"
+    )
+  ).toBe(true);
+});
+
+test("stream events with tool calls has raw message content", async () => {
+  const modelWithTools = model.bind({
+    tools: [anthropicTool],
+    tool_choice: {
+      type: "tool",
+      name: "get_weather",
+    },
+  });
+
+  const wrapper = RunnableLambda.from(async (_, config) => {
+    const res = await modelWithTools.invoke(
+      "What is the weather in London today?",
+      config
+    );
+    return res;
+  });
+  const eventStream = await wrapper.streamEvents(
+    "What is the weather in London today?",
+    {
+      version: "v2",
+    }
+  );
+
+  const chatModelStreamEvents = [];
+  for await (const event of eventStream) {
+    if (event.event === "on_chat_model_stream") {
+      console.log(event);
+      chatModelStreamEvents.push(event);
+    }
+  }
+  expect(chatModelStreamEvents.length).toBeGreaterThan(0);
+  expect(
+    chatModelStreamEvents.every((event) =>
+      Array.isArray(event.data.chunk.content)
+    )
+  ).toBe(true);
+});
+
 test("withStructuredOutput with zod schema", async () => {
   const modelWithTools = model.withStructuredOutput<{ location: string }>(
     zodSchema,