[Bug]: Cannot use Prompt Management w/ API Gateway & Gemini

[konrad-brueggemann-liqid]

What happened?

Hello, I linked my Gemini Provider API Key in Helicone and I can use it for normal use-cases with the OpenAI Client. However, I cannot use the Prompt Management feature, because I get the following error: TypeError: Missing required arguments; Expected either ('messages' and 'model') or ('messages', 'model' and 'stream') arguments to be given.

This is my code:

import openai
import os

from dotenv import load_dotenv
load_dotenv()

client = openai.OpenAI(
    base_url="https://ai-gateway.helicone.ai",
    api_key=os.environ.get("HELICONE_API_KEY")
)

response = client.chat.completions.create(
    model="gemini-2.5-flash",
    prompt_id="my_id",
    environment="production", 
    inputs={"name": "John Doe"}
)

The prompt exists in my dashboard, and I can use it on the playground. I am using the latest OpenAI version (2.8.1) but I also tried older versions up to 0.28.1 and had no success. Why is this?

Relevant log output

Twitter / LinkedIn details

No response

[connortbot]

Hi @konrad-brueggemann-liqid , pass the prompt_id, environment, and inputs in extra_body.

[foxy17]

@connortbot in a similar sitation, using google studio ai byok. This is the code -

const response = await heliconeClient.chat.completions.create({
      model: "gemini-2.5-pro",
      prompt_id: "Eha5Ss",
      environment: getPromptEnvironment(),
      inputs: {
        email_body: emailBody,
      },
    } as any,
    {
      headers: {
        "Helicone-Property-SupplierId": '',
      },
    }
  );

Throws -

[
  {
    "error": {
      "code": 400,
      "message": "* GenerateContentRequest.contents: contents is not specified\n",
      "status": "INVALID_ARGUMENT"
    }
  }
]

I was under the impression that converting the open AI format to google format would be handled by helicone AI gateway, so this should be handled right? The prompt i am using has the input type as string ( could this be an issue?). Is it because the whole prompt is withing system and I need to add something to user?

Also the other place in same codebase I am using helicone it works -

const response = await heliconeClient.chat.completions.create(
      {
        model: "gemini-2.5-pro/google-ai-studio",
        prompt_id: "oTfUzo",
        environment: getPromptEnvironment(),
        messages: [
          {
            role: "user",
            content: [
              {
                type: "image_url",
                image_url: {
                  url: `data:${mimeType};base64,${base64Image}`,
                },
              },
            ],
          },
        ],
      } as any,
      {
        headers: {
          "Helicone-Property-SupplierId": '',
        },
      }
    );

[connortbot]

@foxy17 see the above comment, you should be placing the prompt parameters in extra_body. The errors should be clearer though, will work on that :)