Wie ein Agent Tools nutzt (Grundlagen) — Python (Vollständige Implementierung)

examples/
└── foundations/
    └── tool-calling-basics/
        └── python/
            ├── main.py           # agent loop
            ├── llm.py            # model call + tool definitions
            ├── executor.py       # allowlist check + tool execution
            ├── tools.py          # tools (business logic)
            └── requirements.txt

git clone https://github.com/AgentPatterns-tech/agentpatterns.git
cd examples/foundations/tool-calling-basics/python

pip install -r requirements.txt

export OPENAI_API_KEY="sk-..."

python main.py

from typing import Any

USERS = {
    42: {"id": 42, "name": "Anna", "tier": "pro"},
    7: {"id": 7, "name": "Max", "tier": "free"},
}

BALANCES = {
    42: {"currency": "USD", "value": 128.40},
    7: {"currency": "USD", "value": 0.0},
}


def get_user_profile(user_id: int) -> dict[str, Any]:
    user = USERS.get(user_id)
    if not user:
        return {"error": f"user {user_id} not found"}
    return {"user": user}


def get_user_balance(user_id: int) -> dict[str, Any]:
    balance = BALANCES.get(user_id)
    if not balance:
        return {"error": f"balance for user {user_id} not found"}
    return {"balance": balance}

import json
from typing import Any

from tools import get_user_balance, get_user_profile

TOOL_REGISTRY = {
    "get_user_profile": get_user_profile,
    "get_user_balance": get_user_balance,
}

ALLOWED_TOOLS = {"get_user_profile", "get_user_balance"}


def execute_tool_call(tool_name: str, arguments_json: str) -> dict[str, Any]:
    if tool_name not in ALLOWED_TOOLS:
        return {"error": f"tool '{tool_name}' is not allowed"}

    tool = TOOL_REGISTRY.get(tool_name)
    if tool is None:
        return {"error": f"tool '{tool_name}' not found"}

    try:
        args = json.loads(arguments_json or "{}")
    except json.JSONDecodeError:
        return {"error": "invalid JSON arguments"}

    try:
        result = tool(**args)
    except TypeError as exc:
        return {"error": f"invalid arguments: {exc}"}

    return {"tool": tool_name, "result": result}

import os
from openai import OpenAI

api_key = os.environ.get("OPENAI_API_KEY")

if not api_key:
    raise EnvironmentError(
        "OPENAI_API_KEY is not set.\n"
        "Run: export OPENAI_API_KEY='sk-...'"
    )

client = OpenAI(api_key=api_key)

SYSTEM_PROMPT = """
You are an AI support agent. When you need data, call the available tools.
Once you have enough information, give a short answer.
""".strip()

TOOLS = [
    {
        "type": "function",
        "function": {
            "name": "get_user_profile",
            "description": "Returns user profile by user_id",
            "parameters": {
                "type": "object",
                "properties": {"user_id": {"type": "integer"}},
                "required": ["user_id"],
            },
        },
    },
    {
        "type": "function",
        "function": {
            "name": "get_user_balance",
            "description": "Returns user balance by user_id",
            "parameters": {
                "type": "object",
                "properties": {"user_id": {"type": "integer"}},
                "required": ["user_id"],
            },
        },
    },
]


def ask_model(messages: list[dict]):
    completion = client.chat.completions.create(
        model="gpt-4.1-mini",
        messages=[{"role": "system", "content": SYSTEM_PROMPT}, *messages],
        tools=TOOLS,
        tool_choice="auto",
    )
    return completion.choices[0].message

import json

from executor import execute_tool_call
from llm import ask_model

MAX_STEPS = 6

TASK = "Prepare a short account summary for user_id=42: name, tier, and balance."


def to_assistant_message(message) -> dict:
    tool_calls = []
    for tc in message.tool_calls or []:
        tool_calls.append(
            {
                "id": tc.id,
                "type": "function",
                "function": {
                    "name": tc.function.name,
                    "arguments": tc.function.arguments,
                },
            }
        )
    return {
        "role": "assistant",
        "content": message.content or "",
        "tool_calls": tool_calls,
    }


def run():
    messages: list[dict] = [{"role": "user", "content": TASK}]

    for step in range(1, MAX_STEPS + 1):
        print(f"\n=== STEP {step} ===")
        assistant = ask_model(messages)
        messages.append(to_assistant_message(assistant))

        text = assistant.content or ""
        if text.strip():
            print(f"Assistant: {text.strip()}")

        tool_calls = assistant.tool_calls or []
        if not tool_calls:
            print("\nDone: model finished without a new tool call.")
            return

        for tc in tool_calls:
            print(f"Tool call: {tc.function.name}({tc.function.arguments})")
            execution = execute_tool_call(
                tool_name=tc.function.name,
                arguments_json=tc.function.arguments,
            )
            print(f"Tool result: {execution}")

            messages.append(
                {
                    "role": "tool",
                    "tool_call_id": tc.id,
                    "content": json.dumps(execution, ensure_ascii=False),
                }
            )

    print("\nStop: MAX_STEPS reached.")


if __name__ == "__main__":
    run()

openai>=1.0.0

=== STEP 1 ===
Tool call: get_user_profile({"user_id": 42})
Tool result: {'tool': 'get_user_profile', 'result': {'user': {'id': 42, 'name': 'Anna', 'tier': 'pro'}}}

=== STEP 2 ===
Tool call: get_user_balance({"user_id": 42})
Tool result: {'tool': 'get_user_balance', 'result': {'balance': {'currency': 'USD', 'value': 128.4}}}

=== STEP 3 ===
Assistant: User Anna is a pro tier member with a current balance of 128.4 USD.

Done: model finished without a new tool call.