langchain/libs/experimental/langchain_experimental/tot/prompts.py

import json
from textwrap import dedent
from typing import List

from langchain.prompts import PromptTemplate
from langchain.schema import BaseOutputParser

from langchain_experimental.tot.thought import ThoughtValidity

COT_PROMPT = PromptTemplate(
    template_format="jinja2",
    input_variables=["problem_description", "thoughts"],
    template=dedent(
        """
        You are an intelligent agent that is generating one thought at a time in
        a tree of thoughts setting.

        PROBLEM 
        
        {{problem_description}}
        
        {% if thoughts %}
        THOUGHTS
        
        {% for thought in thoughts %}
        {{ thought }}
        {% endfor %}
        {% endif %}
        
        Let's think step by step.
        """
    ).strip(),
)


class JSONListOutputParser(BaseOutputParser):
    """Class to parse the output of a PROPOSE_PROMPT response."""

    @property
    def _type(self) -> str:
        return "json_list"

    def parse(self, text: str) -> List[str]:
        """Parse the output of an LLM call."""

        json_string = text.split("```json")[1].strip().strip("```").strip()
        try:
            return json.loads(json_string)
        except json.JSONDecodeError:
            return []


PROPOSE_PROMPT = PromptTemplate(
    template_format="jinja2",
    input_variables=["problem_description", "thoughts", "n"],
    output_parser=JSONListOutputParser(),
    template=dedent(
        """
        You are an intelligent agent that is generating thoughts in a tree of
        thoughts setting.

        The output should be a markdown code snippet formatted as a JSON list of
        strings, including the leading and trailing "```json" and "```":

        ```json
        [
            "<thought-1>",
            "<thought-2>",
            "<thought-3>"
        ]
        ```

        PROBLEM

        {{ problem_description }}

        {% if thoughts %}
        VALID THOUGHTS

        {% for thought in thoughts %}
        {{ thought }}
        {% endfor %}

        Possible next {{ n }} valid thoughts based on the last valid thought:
        {% else %}

        Possible next {{ n }} valid thoughts based on the PROBLEM:
        {%- endif -%}
        """
    ).strip(),
)


class CheckerOutputParser(BaseOutputParser):
    def parse(self, text: str) -> ThoughtValidity:
        """Parse the output of the language model."""
        text = text.upper()
        if "INVALID" in text:
            return ThoughtValidity.INVALID
        elif "INTERMEDIATE" in text:
            return ThoughtValidity.VALID_INTERMEDIATE
        elif "VALID" in text:
            return ThoughtValidity.VALID_FINAL
        else:
            return ThoughtValidity.INVALID

    @property
    def _type(self) -> str:
        return "tot_llm_checker_output"


CHECKER_PROMPT = PromptTemplate(
    input_variables=["problem_description", "thoughts"],
    template=dedent(
        """
        You are an intelligent agent, validating thoughts of another intelligent agent.

        PROBLEM 
        
        {problem_description}

        THOUGHTS
        
        {thoughts}

        Evaluate the thoughts and respond with one word.

        - Respond VALID if the last thought is a valid final solution to the
        problem.
        - Respond INVALID if the last thought is invalid.
        - Respond INTERMEDIATE if the last thought is valid but not the final
        solution to the problem.

        This chain of thoughts is"""
    ).strip(),
    output_parser=CheckerOutputParser(),
)