output_parser.ts

import { AgentAction, AgentFinish } from "../../schema/index.js";
import { OutputParserException } from "../../schema/output_parser.js";
import { AgentActionOutputParser } from "../types.js";

export class XMLAgentOutputParser extends AgentActionOutputParser {
  lc_namespace = ["langchain", "agents", "xml"];

  static lc_name() {
    return "XMLAgentOutputParser";
  }

  /**
   * Parses the output text from the agent and returns an AgentAction or
   * AgentFinish object.
   * @param text The output text from the agent.
   * @returns An AgentAction or AgentFinish object.
   */
  async parse(text: string): Promise<AgentAction | AgentFinish> {
    if (text.includes("</tool>")) {
      const [tool, toolInput] = text.split("</tool>");
      const _tool = tool.split("<tool>")[1];
      const _toolInput = toolInput.split("<tool_input>")[1];
      return { tool: _tool, toolInput: _toolInput, log: text };
    } else if (text.includes("<final_answer>")) {
      const [, answer] = text.split("<final_answer>");
      return { returnValues: { output: answer }, log: text };
    } else {
      throw new OutputParserException(`Could not parse LLM output: ${text}`);
    }
  }

  getFormatInstructions(): string {
    throw new Error(
      "getFormatInstructions not implemented inside OpenAIFunctionsAgentOutputParser."
    );
  }
}