Membangun Agen di Rumah Secara Gratis: Alat dan Model Open Source

#!/usr/bin/env python3
"""
Agen Penelitian Lokal menggunakan Ollama + LangChain
Prasyarat:
  - ollama serve (berjalan di background)
  - ollama pull mistral
  - pip install langchain langchain-ollama langchain-community duckduckgo-search
"""

import json
from langchain_core.tools import tool
from langchain_core.prompts import ChatPromptTemplate
from langchain_ollama import ChatOllama
from langchain.agents import AgentExecutor, create_react_agent
from duckduckgo_search import DDGS


@tool
def search_web(query: str) -> str:
    """Mencari informasi di web menggunakan DuckDuckGo."""
    try:
        with DDGS() as ddgs:
            results = list(ddgs.text(query, max_results=5))
        if not results:
            return "Tidak ada hasil ditemukan."
        return json.dumps(
            [{"title": r["title"], "snippet": r["body"], "url": r["href"]}
             for r in results],
            indent=2
        )
    except Exception as e:
        return f"Pencarian gagal: {e}"


@tool
def read_file(filepath: str) -> str:
    """Membaca file lokal dan mengembalikan isinya."""
    try:
        with open(filepath, "r") as f:
            return f.read()
    except FileNotFoundError:
        return f"File tidak ditemukan: {filepath}"


@tool
def calculate(expression: str) -> str:
    """Mengevaluasi ekspresi aritmatika sederhana dengan aman."""
    try:
        result = eval(expression, {"__builtins__": {}}, {})
        return str(result)
    except Exception as e:
        return f"Kesalahan perhitungan: {e}"


llm = ChatOllama(
    model="mistral",
    base_url="http://localhost:11434",
    temperature=0.3,
)

prompt = ChatPromptTemplate.from_messages([
    ("system", """Kamu adalah asisten penelitian. Jawab pertanyaan menggunakan alatmu.

Alat tersedia: {tool_names}
Deskripsi alat: {tools}

Ikuti format ini dengan tepat:
Thought: Apa yang perlu saya temukan?
Action: nama_alat
Action Input: input untuk alat
Observation: hasil alat
... (ulangi sesuai kebutuhan)
Thought: Sekarang saya memiliki cukup informasi.
Final Answer: jawaban lengkapmu"""),
    ("user", "{input}"),
    ("placeholder", "{agent_scratchpad}"),
])

tools = [search_web, read_file, calculate]
agent = create_react_agent(llm, tools, prompt)
agent_executor = AgentExecutor(
    agent=agent,
    tools=tools,
    verbose=True,
    max_iterations=8,
    handle_parsing_errors=True,
)

if __name__ == "__main__":
    result = agent_executor.invoke({
        "input": "Apa tiga LLM open source paling populer saat ini? Berikan nama dan satu karakteristik kunci masing-masing."
    })
    print(f"\nJAWABAN AKHIR:\n{result['output']}")

import sqlite3

@tool
def query_database(sql: str) -> str:
    """Menjalankan kueri SQL read-only pada database lokal."""
    try:
        conn = sqlite3.connect("data.db")
        cursor = conn.cursor()
        cursor.execute(sql)
        rows = cursor.fetchall()
        columns = [desc[0] for desc in cursor.description]
        conn.close()
        return json.dumps([dict(zip(columns, row)) for row in rows], indent=2)
    except Exception as e:
        return f"Kesalahan database: {e}"

from sentence_transformers import SentenceTransformer
import chromadb

model = SentenceTransformer("all-MiniLM-L6-v2")
client = chromadb.Client()
collection = client.create_collection("docs")

@tool
def search_docs(query: str) -> str:
    """Mencari dokumen lokal berdasarkan kemiripan semantik."""
    results = collection.query(
        query_embeddings=[model.encode(query).tolist()],
        n_results=3
    )
    return json.dumps(results["documents"][0], indent=2)

FROM python:3.12-slim
RUN pip install langchain langchain-ollama langchain-community duckduckgo-search
COPY research_agent.py .
ENV OLLAMA_HOST=host.docker.internal:11434
CMD ["python3", "research_agent.py"]

def run_pipeline(question: str) -> str:
    research_result = researcher.invoke({"input": question})
    final_output = writer.invoke({
        "input": f"Berdasarkan penelitian ini, tulis ringkasan yang jelas:\n{research_result['output']}"
    })
    return final_output["output"]