googleapis / googleapis/python-genai

gemini-3.5-flash-lite rejects zero budget at thinking mode

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#2,936 3 comments 0 reactions 1 assignee Claimed by @Venkaiahbabuneelam View on GitHub
priority: p2 type: bug
Dominant language
Python
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Description

With the latest version of python-genai, gemini-3.5-flash-lite is not able to work when "thinkingBudget=0", with "thinkingBudget=None" works, but other models working fine with a budget of zero.

But, using a simple script with python httpx (no google-genai involved) I got this:

```
┌─────────────────────────────────────┬─────────────────┐
│ gemini-3.5-flash-lite │ Raw REST result │
├─────────────────────────────────────┼─────────────────┤
│ thinkingBudget: 0 │ 400 │
├─────────────────────────────────────┼─────────────────┤
│ omitted │ 200 OK │
├─────────────────────────────────────┼─────────────────┤
│ -1 (dynamic) │ 200 OK │
├─────────────────────────────────────┼─────────────────┤
│ 512 │ 200 OK │
├─────────────────────────────────────┼─────────────────┤
│ (control) gemini-2.5-flash-lite + 0 │ 200 OK │
└─────────────────────────────────────┴─────────────────┘
```

I tested all other models, including 3.8 family without issues, this is the only model with this problem.

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