The tool loop

1import json
2from openai import OpenAI
3 
4client = OpenAI(base_url="https://ai.upfyn.com/v1", api_key=KEY, max_retries=0)
5 
6MAX_STEPS = 8          # a runaway agent is the most expensive bug you can ship
7 
8 
9def run_agent(task: str, tools: list, executor, run_id: str) -> str:
10    messages = [
11        {"role": "system", "content": "Use the tools available. Stop when the task is done."},
12        {"role": "user", "content": task},
13    ]
14 
15    for step in range(MAX_STEPS):
16        response = client.chat.completions.create(
17            model="upfyn-yuva",
18            messages=messages,
19            tools=tools,
20            extra_body={"chat_ref": run_id},     # ties every turn together in Logs
21        )
22        message = response.choices[0].message
23 
24        # No tool calls means the model is answering, not working.
25        if not message.tool_calls:
26            return message.content
27 
28        messages.append(message)
29 
30        for call in message.tool_calls:
31            messages.append({
32                "role": "tool",
33                "tool_call_id": call.id,
34                "content": execute(executor, call),
35            })
36 
37    return "Stopped: the task did not finish within the step limit."
38 
39 
40def execute(executor, call) -> str:
41    """Always returns a string. A tool that raises must not end the run."""
42    try:
43        args = json.loads(call.function.arguments)
44    except json.JSONDecodeError:
45        # The model generated the arguments, so malformed JSON is a normal event.
46        return json.dumps({"error": "arguments were not valid JSON"})
47 
48    try:
49        return json.dumps(executor(call.function.name, args))
50    except PermissionError as err:
51        return json.dumps({"error": f"not permitted: {err}"})
52    except Exception as err:
53        # Feed the failure back. The model will usually correct itself.
54        return json.dumps({"error": str(err)[:500]})

1ALLOWED = {"search_orders", "get_order", "send_receipt"}
2 
3def executor(name: str, args: dict):
4    # The allowlist lives HERE, not in the tool description. A description is a
5    # suggestion to the model; this is the boundary that actually holds.
6    if name not in ALLOWED:
7        raise PermissionError(f"unknown tool {name}")
8 
9    if name == "send_receipt":
10        if not args.get("order_id"):
11            raise ValueError("order_id is required")
12        if not user_owns_order(current_user, args["order_id"]):
13            raise PermissionError("that order belongs to someone else")
14        return send_receipt(args["order_id"])
15    ...