Prolog

#!pip install langchain-prolog

from langchain_prolog import PrologConfig, PrologRunnable, PrologTool

TEST_SCRIPT = "family.pl"

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.
    """,
)

#!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

model = ChatOpenAI(model="gpt-4o-mini")
model_with_tools = model.bind_tools([prolog_tool])

query = "Who are John's children?"
messages = [HumanMessage(query)]
response = model_with_tools.invoke(messages)

messages.append(response)
response.tool_calls[0]

{'name': 'family_query',
 'args': {'men': 'john', 'women': None, 'child': None},
 'id': 'call_gH8rWamYXITrkfvRP2s5pkbF',
 'type': 'tool_call'}

tool_msg = prolog_tool.invoke(response.tool_calls[0])

messages.append(tool_msg)
tool_msg

ToolMessage(content='[{"Women": "bianca", "Child": "mary"}, {"Women": "bianca", "Child": "michael"}]', name='family_query', tool_call_id='call_gH8rWamYXITrkfvRP2s5pkbF')

answer = model_with_tools.invoke(messages)
print(answer.content)

John has two children: Mary and Michael, with Bianca as their mother.

#!pip install langgraph

from langchain.agents import create_agent


agent_executor = create_agent(model, [prolog_tool])

messages = agent_executor.invoke({"messages": [("human", query)]})

messages["messages"][-1].pretty_print()

================================== Ai Message ==================================

John has two children: Mary and Michael, with Bianca as their mother.