Source code for langchain.chains.llm_summarization_checker.base

"""Chain for summarization with self-verification."""

from __future__ import annotations

import warnings
from pathlib import Path
from typing import Any, Dict, List, Optional

from langchain_core._api import deprecated
from langchain_core.callbacks import CallbackManagerForChainRun
from langchain_core.language_models import BaseLanguageModel
from langchain_core.prompts.prompt import PromptTemplate
from pydantic import ConfigDict, model_validator

from langchain.chains.base import Chain
from langchain.chains.llm import LLMChain
from langchain.chains.sequential import SequentialChain

PROMPTS_DIR = Path(__file__).parent / "prompts"

CREATE_ASSERTIONS_PROMPT = PromptTemplate.from_file(PROMPTS_DIR / "create_facts.txt")
CHECK_ASSERTIONS_PROMPT = PromptTemplate.from_file(PROMPTS_DIR / "check_facts.txt")
REVISED_SUMMARY_PROMPT = PromptTemplate.from_file(PROMPTS_DIR / "revise_summary.txt")
ARE_ALL_TRUE_PROMPT = PromptTemplate.from_file(PROMPTS_DIR / "are_all_true_prompt.txt")


def _load_sequential_chain(
    llm: BaseLanguageModel,
    create_assertions_prompt: PromptTemplate,
    check_assertions_prompt: PromptTemplate,
    revised_summary_prompt: PromptTemplate,
    are_all_true_prompt: PromptTemplate,
    verbose: bool = False,
) -> SequentialChain:
    chain = SequentialChain(
        chains=[
            LLMChain(
                llm=llm,
                prompt=create_assertions_prompt,
                output_key="assertions",
                verbose=verbose,
            ),
            LLMChain(
                llm=llm,
                prompt=check_assertions_prompt,
                output_key="checked_assertions",
                verbose=verbose,
            ),
            LLMChain(
                llm=llm,
                prompt=revised_summary_prompt,
                output_key="revised_summary",
                verbose=verbose,
            ),
            LLMChain(
                llm=llm,
                output_key="all_true",
                prompt=are_all_true_prompt,
                verbose=verbose,
            ),
        ],
        input_variables=["summary"],
        output_variables=["all_true", "revised_summary"],
        verbose=verbose,
    )
    return chain


[docs] @deprecated( since="0.2.13", message=( "See LangGraph guides for a variety of self-reflection and corrective " "strategies for question-answering and other tasks: " "https://langchain-ai.github.io/langgraph/tutorials/rag/langgraph_self_rag/" ), removal="1.0", ) class LLMSummarizationCheckerChain(Chain): """Chain for question-answering with self-verification. Example: .. code-block:: python from langchain_community.llms import OpenAI from langchain.chains import LLMSummarizationCheckerChain llm = OpenAI(temperature=0.0) checker_chain = LLMSummarizationCheckerChain.from_llm(llm) """ sequential_chain: SequentialChain llm: Optional[BaseLanguageModel] = None """[Deprecated] LLM wrapper to use.""" create_assertions_prompt: PromptTemplate = CREATE_ASSERTIONS_PROMPT """[Deprecated]""" check_assertions_prompt: PromptTemplate = CHECK_ASSERTIONS_PROMPT """[Deprecated]""" revised_summary_prompt: PromptTemplate = REVISED_SUMMARY_PROMPT """[Deprecated]""" are_all_true_prompt: PromptTemplate = ARE_ALL_TRUE_PROMPT """[Deprecated]""" input_key: str = "query" #: :meta private: output_key: str = "result" #: :meta private: max_checks: int = 2 """Maximum number of times to check the assertions. Default to double-checking.""" model_config = ConfigDict( arbitrary_types_allowed=True, extra="forbid", ) @model_validator(mode="before") @classmethod def raise_deprecation(cls, values: Dict) -> Any: if "llm" in values: warnings.warn( "Directly instantiating an LLMSummarizationCheckerChain with an llm is " "deprecated. Please instantiate with" " sequential_chain argument or using the from_llm class method." ) if "sequential_chain" not in values and values["llm"] is not None: values["sequential_chain"] = _load_sequential_chain( values["llm"], values.get("create_assertions_prompt", CREATE_ASSERTIONS_PROMPT), values.get("check_assertions_prompt", CHECK_ASSERTIONS_PROMPT), values.get("revised_summary_prompt", REVISED_SUMMARY_PROMPT), values.get("are_all_true_prompt", ARE_ALL_TRUE_PROMPT), verbose=values.get("verbose", False), ) return values @property def input_keys(self) -> List[str]: """Return the singular input key. :meta private: """ return [self.input_key] @property def output_keys(self) -> List[str]: """Return the singular output key. :meta private: """ return [self.output_key] def _call( self, inputs: Dict[str, Any], run_manager: Optional[CallbackManagerForChainRun] = None, ) -> Dict[str, str]: _run_manager = run_manager or CallbackManagerForChainRun.get_noop_manager() all_true = False count = 0 output = None original_input = inputs[self.input_key] chain_input = original_input while not all_true and count < self.max_checks: output = self.sequential_chain( {"summary": chain_input}, callbacks=_run_manager.get_child() ) count += 1 if output["all_true"].strip() == "True": break if self.verbose: print(output["revised_summary"]) # noqa: T201 chain_input = output["revised_summary"] if not output: raise ValueError("No output from chain") return {self.output_key: output["revised_summary"].strip()} @property def _chain_type(self) -> str: return "llm_summarization_checker_chain"
[docs] @classmethod def from_llm( cls, llm: BaseLanguageModel, create_assertions_prompt: PromptTemplate = CREATE_ASSERTIONS_PROMPT, check_assertions_prompt: PromptTemplate = CHECK_ASSERTIONS_PROMPT, revised_summary_prompt: PromptTemplate = REVISED_SUMMARY_PROMPT, are_all_true_prompt: PromptTemplate = ARE_ALL_TRUE_PROMPT, verbose: bool = False, **kwargs: Any, ) -> LLMSummarizationCheckerChain: chain = _load_sequential_chain( llm, create_assertions_prompt, check_assertions_prompt, revised_summary_prompt, are_all_true_prompt, verbose=verbose, ) return cls(sequential_chain=chain, verbose=verbose, **kwargs)