Certain LLM APIs (notably https://ai.ezif.in/ and likely other kivest endpoints) default to streaming Server-Sent Events (SSE) responses instead of returning standard JSON. The OpenEvolve LLM client expects non-streaming JSON with a choices array, causing the error:

'str' object has no attribute 'choices'

Root Cause
The API at https://ai.ezif.in/chat/completions returns SSE data by default:

data: {"id":"chatcmpl-xxx","object":"chat.completion.chunk",...}
data: [DONE]

When the OpenAI client parses this raw text string, it becomes a string rather than a response object, so accessing .choices fails.

Fix
Add "stream": false to the API request parameters in openevolve/llm/openai.py:

# In generate_with_context method, after building params:
# Always request non-streaming responses
params["stream"] = False

I think this is standard OpenAI API behavior and doesn't harm any other API endpoints.

Reproduction Steps

• Configure OpenEvolve with an API that defaults to streaming (e.g., kivest/ezif)
• Run any evolution iteration
• Error appears in logs after successful HTTP request

Additional Notes

• The fix is in openevolve/llm/openai.py line ~170
• This is a one-line fix that makes the behavior explicit
• The streaming parameter is part of the OpenAI API spec and I believe it is supported by all compatible endpoints