tools parameter is silently ignored when max_turns is not set

[peterbaksa]

Problem

When calling client.chat.completions.create() with tools= but without max_turns=, the tools parameter is silently ignored. The model receives no tool definitions and responds as if no tools were provided — with no warning or error.

Example

import aisuite as ai
from datetime import datetime

def get_current_time():
    """Returns the current time as a string."""
    return datetime.now().strftime("%H:%M:%S")

client = ai.Client()
messages = [{"role": "user", "content": "What time is it?"}]

# WITHOUT max_turns — tools silently ignored, model says "I can't tell the time"
response = client.chat.completions.create(
    model="openai:gpt-4o",
    messages=messages,
    tools=[get_current_time],
)
print(response.choices[0].message.content)
# >> "I'm unable to provide real-time information..."

# WITH max_turns — works correctly
response = client.chat.completions.create(
    model="openai:gpt-4o",
    messages=messages,
    tools=[get_current_time],
    max_turns=2,
)
print(response.choices[0].message.content)
# >> "The current time is 23:42:32."

Where the problem is

In aisuite/client.py, the create() method has this condition:

if max_turns is not None and tools is not None:
    return self._tool_runner(provider, model_name, messages.copy(), tools, max_turns, **kwargs)

# falls through to standard completion — tools are discarded
response = provider.chat_completions_create(model_name, messages, **kwargs)

When max_turns is None, the code falls through to a standard completion call where tools are never passed to the provider. No warning is raised.

Proposed solution

At minimum, raise a warning when tools is provided without max_turns:

if tools is not None and max_turns is None:
    import warnings
    warnings.warn(
        "tools parameter is ignored without max_turns. "
        "Set max_turns (e.g. max_turns=1) to enable tool calling.",
        UserWarning,
    )

A better approach might be to default max_turns=1 when tools is provided, so that tool calling works out of the box:

if tools is not None and max_turns is None:
    max_turns = 1

This would match user expectations — if you pass tools, you expect them to be used.