openai[patch]: Adds OpenAI system_fingerprint to response_metadata (#…

…6107)

* Adds OpenAI system_fingerprint to response_metadata

* Fix lint

libs/langchain-openai/src/chat_models.ts

@@ -154,11 +154,18 @@ function openAIResponseToChatMessage(
       if (includeRawResponse !== undefined) {
         additional_kwargs.__raw_response = rawResponse;
       }
+      let response_metadata: Record<string, unknown> | undefined;
+      if (rawResponse.system_fingerprint) {
+        response_metadata = {
+          system_fingerprint: rawResponse.system_fingerprint,
+        };
+      }
       return new AIMessage({
         content: message.content || "",
         tool_calls: toolCalls,
         invalid_tool_calls: invalidToolCalls,
         additional_kwargs,
+        response_metadata,
         id: rawResponse.id,
       });
     }
@@ -681,6 +688,9 @@ export class ChatOpenAI<
       const generationInfo: Record<string, any> = { ...newTokenIndices };
       if (choice.finish_reason !== undefined) {
         generationInfo.finish_reason = choice.finish_reason;
+        // Only include system fingerprint in the last chunk for now
+        // to avoid concatenation issues
+        generationInfo.system_fingerprint = data.system_fingerprint;
       }
       if (this.logprobs) {
         generationInfo.logprobs = choice.logprobs;

libs/langchain-openai/src/tests/chat_models-extended.int.test.ts

@@ -26,10 +26,18 @@ test("Test ChatOpenAI seed", async () => {
     seed: 123454930394983,
   });
   const message = new HumanMessage("Say something random!");
+
   const res = await chat.invoke([message]);
-  console.log(JSON.stringify(res));
 
   const res2 = await chat.invoke([message]);
+
+  expect(res.response_metadata.system_fingerprint).toBeDefined();
+  expect(res2.response_metadata.system_fingerprint).toBeDefined();
+
+  // These are unfortunately not consistently the same
+  delete res.response_metadata.system_fingerprint;
+  delete res2.response_metadata.system_fingerprint;
+
   const resAsObject = {
     ...res,
     id: undefined,
@@ -40,7 +48,6 @@ test("Test ChatOpenAI seed", async () => {
     id: undefined,
     lc_kwargs: { ...res2.lc_kwargs, id: undefined },
   };
-
   expect(resAsObject).toEqual(res2AsObject);
 });