LangChain으로 구조화된 LLM 출력 제어하기 (TypeScript)

import { ChatAnthropic } from "@langchain/anthropic"
import { z } from "zod"

const model = new ChatAnthropic({
  model: "claude-3-5-sonnet-20240620",
  temperature: 0
})

const joke = z.object({
  setup: z.string().describe("The setup of the joke"),
  punchline: z.string().describe("The punchline to the joke"),
  rating: z.number().optional().describe("How funny the joke is, from 1 to 10"),
})

const structuredLlm = model.withStructuredOutput(joke, { name: 'joke' })
const response = await structuredLlm.invoke("Tell me a joke about cats")

console.log(response)
// {
//   setup: "Why don't cats play poker in the wild?",
//   punchline: "Too many cheetahs!",
//   rating: 7
// }

// 설명 없음 (모델이 필드 이름만으로 추론)
const schema = z.object({
  s: z.string(),
  p: z.string(),
})

// 설명 있음 (권장)
const schema = z.object({
  setup: z.string().describe("The setup of the joke"),
  punchline: z.string().describe("The punchline to the joke"),
})

import { z } from "zod";
import { StructuredOutputParser } from "@langchain/core/output_parsers";

const zodSchema = z.object({
  name: z.string().describe("name of an actor"),
  film_names: z
    .array(z.string())
    .describe("list of names of films they starred in"),
});

const parser = StructuredOutputParser.fromZodSchema(zodSchema);

const misformatted = "{'name': 'Tom Hanks', 'film_names': ['Forrest Gump']}";

await parser.parse(misformatted);
// Error: Failed to parse. Text: "{'name': 'Tom Hanks', 'film_names': ['Forrest Gump']}".
// Error: SyntaxError: Expected property name or '}' in JSON at position 1

import { ChatAnthropic } from "@langchain/anthropic";
import { OutputFixingParser } from "langchain/output_parsers";

const model = new ChatAnthropic({
  model: "claude-3-sonnet-20240229",
  maxTokens: 512,
  temperature: 0.1,
});

const parserWithFix = OutputFixingParser.fromLLM(model, parser);

const result = await parserWithFix.parse(misformatted);
console.log(result);
// {
//   name: "Tom Hanks",
//   film_names: ["Forrest Gump", "Saving Private Ryan", "Cast Away", "Catch Me If You Can"]
// }