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Document 2.5 Flash thinking in REST/curl examples #723

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Document 2.5 Flash thinking in REST/curl examples#723
#729
@maflcko

Description

@maflcko
maflcko
opened on Apr 18, 2025

Description of the feature request:

I was looking for documentation on how to use the new 2.5 Flash Thinking model with REST/curl. However, I couldn't find any examples or docs on how to toggle the thinking mode or set the thinking budget via curl.

I tried the following search: https://github.com/search?q=repo%3Agoogle-gemini%2Fcookbook+thinking+path%3Aquickstarts%2Frest+&type=code

What problem are you trying to solve with this feature?

No response

Any other information you'd like to share?

No response

Activity

X901

X901 commented on Apr 18, 2025

@X901
X901
on Apr 18, 2025

I ask the same thing here

but I don't get response

I didn't get any errors but it's not feel as it realy disabled as the OpenRouter model

const requestBody = {
            contents: [{
                parts: [
                    { text: preamble },
                    { text: prompt }
                ]
            }],
            generationConfig: {
                temperature: 0.3,   
                response_mime_type: "application/json",
                thinkingConfig: { thinkingBudget: 0 }
                ,response_schema: {
                    type: "object",
                    properties: {
                        translations: {
                            type: "array",
                            items: { type: "string" }
                        }
                    },
                    required: ["array"]
                }
            }
        };
andycandy

andycandy commented on Apr 19, 2025

@andycandy
andycandy
on Apr 19, 2025
Collaborator

Here this is how you do it:

prompt = """
    You are playing the 20 question game. You know that what you are looking for
    is a aquatic mammal that doesn't live in the sea, and that's smaller than a
    cat. What could that be and how could you make sure?
"""

MODEL_ID = "gemini-2.5-flash-preview-04-17"
url = f"https://generativelanguage.googleapis.com/v1beta/models/{MODEL_ID}:generateContent?key={GOOGLE_API_KEY}"  

headers = {
    'Content-Type': 'application/json',
}
data = {
    "contents": [{
            "parts":[
                {"text": prompt}
            ]
        }],
    "generationConfig": {
        "thinkingConfig": {
            "thinkingBudget": 0
        }
    }
}
response = requests.post(
    url,
    headers=headers,
    data=json.dumps(data)
)

Output:

{
    "candidates": [
        {
            "content": {
                "parts": [
                    {
                        "text": "Okay, playing 20 Questions with those constraints! Here's what fits the criteria and how to refine:\n\n**What it could be:**\n\nGiven the constraints \u2013 an aquatic mammal that *doesn't* live in the sea and is smaller than a cat \u2013 the most likely candidate is a. .................."
                    }
                ],
                "role": "model"
            },
            "finishReason": "STOP",
            "index": 0
        }
    ],
    "usageMetadata": {
        "promptTokenCount": 58,
        "candidatesTokenCount": 609,
        "totalTokenCount": 667,
        "promptTokensDetails": [
            {
                "modality": "TEXT",
                "tokenCount": 58
            }
        ]
    },
    "modelVersion": "gemini-2.5-flash-preview-04-17"
}

Here you can see it didn't use any thinking token.

Moreover if you rerun the same code but without limiting the token you get this output:

Code:

#before and after stays the same
data = {
    "contents": [{
            "parts":[
                {"text": prompt}
            ]
        }],
}

Output:

{
    "candidates": [
        {
            "content": {
                "parts": [
                    {
                        "text": "Okay, let's break down the clues:\n\n1.  **Aquatic Mammal:** Lives in or spends significant time in water, and is a mammal ..............."
                    }
                ],
                "role": "model"
            },
            "finishReason": "STOP",
            "index": 0
        }
    ],
    "usageMetadata": {
        "promptTokenCount": 58,
        "candidatesTokenCount": 3622,
        "totalTokenCount": 3680,
        "promptTokensDetails": [
            {
                "modality": "TEXT",
                "tokenCount": 58
            }
        ],
        "thoughtsTokenCount": 2696
    },
    "modelVersion": "gemini-2.5-flash-preview-04-17"
}
andycandy

andycandy commented on Apr 19, 2025

@andycandy
andycandy
on Apr 19, 2025
Collaborator

@Giom-V Regarding this query should I make a new Get_started_with_thinking_REST notebook to address this?

andycandy
mentioned this on Apr 20, 2025
maflcko

maflcko commented on Apr 21, 2025

@maflcko
maflcko
on Apr 21, 2025
Author

The docs are also here: https://ai.google.dev/gemini-api/docs/thinking#set-budget

So I'll close this for now, because my immediate question has been answered. The notebook can still be added, if needed, or course.

maflcko
closed this as completedon Apr 21, 2025
X901

X901 commented on Apr 21, 2025

@X901
X901
on Apr 21, 2025

I tried it, it's too slow as if thinking is still enable when I use the Google AI Studio

but in OpenRouter it faster like Flash 2.0

why performance are different ?

maflcko

maflcko commented on Apr 21, 2025

@maflcko
maflcko
on Apr 21, 2025
Author

It could be due to https://twitter.com/OfficialLoganK/status/1912986097765789782, but I don't have any insight here.

In some rare cases, the model still thinks a little even with thinking budget = 0, we are hoping to fix this before we make this model stable and you won't be billed for thinking. The thinking budget = 0 is what triggers the billing switch.

github-actions
mentioned this in 3 issues on May 1, 2025
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        Document 2.5 Flash thinking in REST/curl examples · Issue #723 · google-gemini/cookbook