Re: Amazing work on bug fixing

Thank you very much! That is a lot of great detail.

Do you use Gemini on the command line, the Web interface (More uploads /
Import code directly from Sourceforge, or local git repository?), or via
some IDE (Google AI Studio?)? Do you have a GEMINI.md file? Is that where
you configure Extended Thinking?

Thanks again!!

              -s

On Fri, Jun 19, 2026 at 11:15 AM David Scherfgen <[email protected]>
wrote:

> Thanks, Stavros!
>
> When the "Extended Thinking" mode of Gemini 3.1 Pro was launched, I
> decided to give it a try, after previous attempts with Gemini 3.1 Pro in
> normal mode as well as ChatGPT and Claude weren't very successful.
> Extended Thinking is really a breakthrough.
>
> I usually write the prompt as follows:
>
> We're debugging the Maxima Computer Algebra System written in Lisp. There
>> is a bug in the *[module name]* module that can be reproduced as follows:
>> ----------
>> *[Code example]*
>> ----------
>> As you can see, *[actual behavior]*, while we would expect *[correct
>> behavior]*.
>>
> *[Any notable observations, e.g. similar cases that work correctly]*
>
> ----------
>> Here's a trace:
>> *[Trace of important functions or stack trace in case of a Lisp error]*
>> ----------
>> Your task is to thoroughly investigate this problem, explain in detail
>> every step that causes it, and find a fix for it. Ideally, the fix should
>> be minimally invasive.
>> ----------
>> Relevant sections of Maxima's source code:
>> ----------
>> *[Source code]*
>>
>
> When pasting source code:
>
>    - Strip away everything that's clearly not involved in the problem.
>    - Ideally, include every function that gets called during the
>    reproduction of the bug.
>    - Be patient, as pasting into Gemini's prompt textbox can sometimes
>    take a lot of time (the browser may even ask you if you want to wait or
>    close the page - wait).
>
> Now Gemini will think for a while.
> When it comes back with an answer:
>
>    - Make sure that the selected model is still "Gemini 3.1 Pro
>    (Extended)". It eats your quota really quickly (there's a limit that resets
>    every 5 hours + a weekly limit), and then it will fall back to a simpler
>    model, which almost never comes up with anything useful. You can also
>    notice by how quickly it responds.
>    - Be *extremely critical*. LLMs are incredibly good at selling, they
>    will make it sound like it's 100% sure that they're right.
>    - If you find the answer convincing, test the proposed fix against the
>    problem and the test suite.
>
> If it's an obvious case where you can clearly see that the fix is correct,
> you're done.
> If it's a more difficult case, let Gemini regenerate the answer a few
> times to help you decide. See if it always finds the same fix or different
> ones.
>
> In case you get mostly incorrect fixes:
>
>    - *Don't continue the conversation for too long*, as it will
>    eventually forget the first part of it, which contains the highly important
>    source code. LLMs have a limited context window. If the conversation gets
>    too long, it starts forgetting things said earlier.
>    - Instead, edit your initial prompt and include a section like: "You
>    previously proposed the following fixes, which didn't work: [...]". Include
>    a short description for every proposed fix and why it wasn't working (e.g.
>    it broke certain tests). If editing the initial prompt is not possible
>    because you have sent follow-up prompts already, you can "fork" the
>    conversation after the first reply, and then you will be able to edit the
>    initial prompt in the forked conversation.
>
> I hope this helps!
>
> Best regards
> David Scherfgen
>
> Am Fr., 19. Juni 2026 um 16:19 Uhr schrieb Stavros Macrakis <
> [email protected]>:
>
>> David,
>>
>> Thank you very much for contributing so many bug fixes to Maxima!
>>
>> I think you've mentioned that you use an LLM to help you out. Could you
>> tell us more about your setup and what you've learned about working
>> effectively with it?
>>
>> Thanks!
>>
>>           -s
>>
>>

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