dify Error 400: 'stop' parameter not supported by o4-mini` model

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Dify version

1.2.0

Cloud or Self Hosted

Self Hosted (Docker)

Steps to reproduce

I have updated the OpenAI plugin, which added two O4-Mini models. When I try to use both models, I encounter the following error:

[models] Bad Request Error, Error code: 400 - {'error': {'message': "Unsupported parameter: 'stop' is not supported with this model.", 'type': 'invalid_request_error', 'param': 'stop', 'code': 'unsupported_parameter'}}

✔️ Expected Behavior

The model should work fine without returning an error.

❌ Actual Behavior

The model returns a 400 Bad Request error with the message indicating that the stop parameter is not supported.

Apr 28 '25 07:04 MitraSafarinejad

The error you're encountering is due to the 'stop' parameter not being supported by the O4-Mini model. In the Dify codebase, the ModelConfigConverter class processes model configurations and removes unsupported parameters like 'stop' before finalizing the configuration ^[1].

To resolve this issue, you can modify the configuration to exclude the 'stop' parameter when using the O4-Mini model. This involves ensuring that the 'stop' parameter is not included in the completion parameters for these models. If you have control over the code where the model is invoked, you can adjust the parameters accordingly to prevent the 'stop' parameter from being passed to the O4-Mini model.

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