"""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)
