How to extract GPT-5 reasoning summaries with @langchain/openai?

OSS Product Help LangChain
15

hi @AMuresan

in your case, when using chains, follow this:

import { ChatOpenAI } from "@langchain/openai";
import * as dotenv from "dotenv";
import { PromptTemplate } from "@langchain/core/prompts";
import { z } from "zod";

dotenv.config();

const Result = z
  .object({
    result: z.string().describe("Healthy lifestyle"),
  })
  .describe("Healthy lifestyle coach");

class MyLLM {
  // private LLM: ReturnType<(ChatOpenAI['withConfig'])>;
  private LLM: ChatOpenAI;

  private getLLM() {
    if (!this.LLM) {
      this.LLM = new ChatOpenAI({
        model: "gpt-5",
        useResponsesApi: true,
        /**
         * this won't work because the reasoning config is not set on the LLM instance
         *
         * @see BaseChatOpenAI
         *
         * this.reasoning =
         *   fields?.reasoning ?? fields?.reasoningEffort
         *     ? { effort: fields.reasoningEffort }
         *     : undefined;
         */
        // reasoning: { effort: "low", summary: "detailed" },
        // reasoningEffort: "medium",
      });
    }
    return this.LLM;
  }

  initializa() {
    const llm = this.getLLM();
    const prompt = PromptTemplate.fromTemplate(
      "Is sport necessary for healthy life?",
    );
    const structuredLlm = llm.withStructuredOutput(Result, {
      name: "result",
      method: "jsonSchema",
      strict: true,
      includeRaw: true,
    });

    let chain = prompt.pipe(structuredLlm);

    // chain = chain.pipe(async (response) => {
    //   const formatted_response = JSON.parse(
    //     response.filter((item) => item["type"] === "text")[0]["text"],
    //   ) as Record<string, boolean>;
    //   return formatted_response;
    // });

    return chain.withRetry({ stopAfterAttempt: 5 }).withConfig({
      // @ts-ignore
      reasoning: {
        effort: "high",
        summary: "auto" /* summary config if desired */,
      },
    });
  }
}

(async () => {
  const myLLM = new MyLLM();
  const chain = myLLM.initializa();
  const answer = await chain.invoke(
    {},
    {
      /**
       * Or pass reasoning config as a parameter to the invoke method
       */
      // @ts-ignore
      // reasoning: {
      //   effort: "high",
      //   summary: "auto" /* summary config if desired */,
      // },
    },
  );

  console.log(JSON.stringify(answer, null, 2));
})();

Which means:

  • call withConfig and use // @ts-ignore
  • pass configuration to invoke call and use @ts-ignore

It is an issue and will be fixed in the next release

Unable to pass maxTokens and extract Resoning Summary in AzureChatOpenAI