OPENAI_API_KEY missed causes issue on Split&Embed with other providers

[corradodebari]

Checklist

• I have searched the existing issues for similar issues.
• I added a very descriptive title to this issue.
• I have provided sufficient information below to help reproduce this issue.

Summary

Using a "provider": "hosted_vllm", for embedding and chat completion, in a setup without the OPENAI_API_KEY configured in the env, asking for a Split&Embed process, it fails:

2025-Sep-09 13:01:32 (v1.1.5.dev46+g9db833c09) - ERROR    - (api.v1.embed): An exception occurred: The api_key client option must be set either by passing api_key to the client or by setting the OPENAI_API_KEY environment variable
2025-Sep-09 13:01:32 (v1.1.5.dev46+g9db833c09) - INFO     - (uvicorn.access): 127.0.0.1:47764 - "POST /v1/embed/?client=29cac440-d7ef-4d75-8d9d-fbeca4ff8d86 HTTP/1.1" 500

Setting an OPEN_API_KEY, no problem using the hosted_vllm provider.

Steps To Reproduce

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Expected Behavior

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Current Behavior

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Is this a regression?

• Yes, this used to work in a previous version.

Debug info

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• Browser:

Additional Information

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