使用 Prolog 规则生成答案的 LangChain 工具。
概述
PrologTool 类允许生成使用 Prolog 规则生成答案的 langchain 工具。
设置
让我们使用 family.pl 文件中的以下 Prolog 规则：
parent(john, bianca, mary).\ parent(john, bianca, michael).\ parent(peter, patricia, jennifer).\ partner(X, Y) :- parent(X, Y, _).
#!pip install langchain-prolog
from langchain_prolog import PrologConfig, PrologRunnable, PrologTool
TEST_SCRIPT = "family.pl"实例化
首先创建 Prolog 工具：
schema = PrologRunnable.create_schema("parent", ["men", "women", "child"])
config = PrologConfig(
rules_file=TEST_SCRIPT,
query_schema=schema,
)
prolog_tool = PrologTool(
prolog_config=config,
name="family_query",
description="""
Query family relationships using Prolog.
parent(X, Y, Z) implies only that Z is a child of X and Y.
Input can be a query string like 'parent(john, X, Y)' or 'john, X, Y'"
You have to specify 3 parameters: men, woman, child. Do not use quotes.
""",
)调用
将 Prolog 工具与 LLM 和函数调用结合使用
#!pip install python-dotenv
from dotenv import find_dotenv, load_dotenv
load_dotenv(find_dotenv(), override=True)
#!pip install langchain-openai
from langchain.messages import HumanMessage
from langchain_openai import ChatOpenAI要使用该工具，请将其绑定到 LLM 模型：
model = ChatOpenAI(model="gpt-5.4-mini")
model_with_tools = model.bind_tools([prolog_tool])然后查询模型：
query = "Who are John's children?"
messages = [HumanMessage(query)]
response = model_with_tools.invoke(messages)LLM 将使用工具调用请求进行响应：
messages.append(response)
response.tool_calls[0]{'name': 'family_query',
'args': {'men': 'john', 'women': None, 'child': None},
'id': 'call_gH8rWamYXITrkfvRP2s5pkbF',
'type': 'tool_call'}该工具接收此请求并查询 Prolog 数据库：
tool_msg = prolog_tool.invoke(response.tool_calls[0])该工具返回一个包含查询所有解决方案的列表：
messages.append(tool_msg)
tool_msgToolMessage(content='[{"Women": "bianca", "Child": "mary"}, {"Women": "bianca", "Child": "michael"}]', name='family_query', tool_call_id='call_gH8rWamYXITrkfvRP2s5pkbF')然后我们将结果传递给 LLM，LLM 使用工具响应回答原始查询：
answer = model_with_tools.invoke(messages)
print(answer.content)John has two children: Mary and Michael, with Bianca as their mother.链接
将 Prolog 工具与代理结合使用
要使用代理的 Prolog 工具，请将其传递给代理的构造函数：
#!pip install langgraph
from langchain.agents import create_agent
agent_executor = create_agent(model, [prolog_tool])代理接收查询并在需要时使用 Prolog 工具：
messages = agent_executor.invoke({"messages": [("human", query)]})然后代理接收工具响应并生成答案：
messages["messages"][-1].pretty_print()================================== Ai Message ==================================
John has two children: Mary and Michael, with Bianca as their mother.