gemini with tools: list index out of range after max_steps

[andreaskundig]

This code

from lisette import Chat

def adder(a:int,b:int):
    "Add two numbers"
    return a+b

def multer(a:int,b:int):
    "Multiply two numbers"
    return a*b

c = Chat('gemini/gemini-2.5-flash', tools=[adder,multer])
r = c('Use tools to solve 42427928*548749+547892? ')

causes this error

Traceback (most recent call last):
  File "C:\Users\andre\workspace\solveit\lessons\gemini-lisette.py", line 15, in <module>
    r = c('Use tools to solve 42427928*548749+547892? ')
  File "C:\Users\andre\workspace\solveit\lessons\myenv\Lib\site-packages\lisette\core.py", line 307, in __call__
    else: return last(result_gen)             # normal chat behavior
                 ~~~~^^^^^^^^^^^^
  File "C:\Users\andre\workspace\solveit\lessons\myenv\Lib\site-packages\fastcore\basics.py", line 749, in last
    for res in x: pass
               ^
  File "C:\Users\andre\workspace\solveit\lessons\myenv\Lib\site-packages\lisette\core.py", line 288, in _call
    yield from self._call(
        prompt, prefill, temp, think, search, stream, max_steps, step+1,
        final_prompt, tool_choice, **kwargs)
  File "C:\Users\andre\workspace\solveit\lessons\myenv\Lib\site-packages\lisette\core.py", line 277, in _call
    m = res.choices[0].message
        ~~~~~~~~~~~^^^
IndexError: list index out of range

[andreaskundig]

If I look at c.hist, I see that it actually did a tool call and produced an answer that says 'You have no more tool uses.'

[
{'role': 'user', 'content': 'Use tools to solve 42427928*548749+547892? '}, 
Message(content=None, role='assistant', tool_calls=[{'index': 0, 'function': {'arguments': '{"b": 548749, "a": 42427928}', 'name': 'multer'}, 'id': 'call_fea1e149ab3a4ed6b7bb6d42218a', 'type': 'function'}], function_call=None, images=[], thinking_blocks=[{'type': 'thinking', 'thinking': '{"functionCall": {"name": "multer", "args": {"b": 548749, "a": 42427928}}}', 'signature': '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'}], provider_specific_fields=None), 
{'tool_call_id': 'call_fea1e149ab3a4ed6b7bb6d42218a', 'role': 'tool', 'name': 'multer', 'content': '23282283062072'}, 
{'role': 'assistant', 'content': 'You have no more tool uses. Please summarize your findings. If you did not complete your goal please tell the user what further work needs to be done so they can choose how best to proceed.'}
]

[andreaskundig]

The problem does not happen when you allow more steps

r = c('Use tools to solve 42427928*548749+547892? ', max_steps=10)

[andreaskundig]

Solveit has some ideas about how to fix this at the end of this dialog.

I don't know the code well enough to decide which of its propositions makes most sense.