I'm not the one who wrote this code in the first place, but IIRC there was a comment about us doing this to match the behaviour of openai API.

I can consider merging this if you can verify that. Otherwise, I will close this PR as it may not be a bug.

I'm closing this because this is not a valid bug. OAI API having the same "delta":{} on the last message:

data: {"id":"chatcmpl-Ayz7toKtZV6ZO6LnxkfNTvNp6lE8v","object":"chat.completion.chunk","created":1739098013,"model":"gpt-4o-2024-08-06","service_tier":"default","system_fingerprint":"fp_50cad350e4","choices":[{"index":0,"delta":{"role":"assistant","content":"","refusal":null},"logprobs":{"content":[],"refusal":null},"finish_reason":null}]}

data: {"id":"chatcmpl-Ayz7toKtZV6ZO6LnxkfNTvNp6lE8v","object":"chat.completion.chunk","created":1739098013,"model":"gpt-4o-2024-08-06","service_tier":"default","system_fingerprint":"fp_50cad350e4","choices":[{"index":0,"delta":{"content":"Sol"},"logprobs":{"content":[{"token":"Sol","logprob":-4.2846212,"bytes":[83,111,108],"top_logprobs":[{"token":"Ser","logprob":-0.53462136,"bytes":[83,101,114]},{"token":"Qu","logprob":-2.7846212,"bytes":[81,117]},{"token":"Ze","logprob":-2.7846212,"bytes":[90,101]},{"token":"Ep","logprob":-3.0346212,"bytes":[69,112]},{"token":"E","logprob":-3.5346212,"bytes":[69]}]}],"refusal":null},"finish_reason":null}]}

data: {"id":"chatcmpl-Ayz7toKtZV6ZO6LnxkfNTvNp6lE8v","object":"chat.completion.chunk","created":1739098013,"model":"gpt-4o-2024-08-06","service_tier":"default","system_fingerprint":"fp_50cad350e4","choices":[{"index":0,"delta":{},"logprobs":null,"finish_reason":"length"}]}

I'm closing this because this is not a valid bug. OAI API having the same "delta":{} on the last message:

data: {"id":"chatcmpl-Ayz7toKtZV6ZO6LnxkfNTvNp6lE8v","object":"chat.completion.chunk","created":1739098013,"model":"gpt-4o-2024-08-06","service_tier":"default","system_fingerprint":"fp_50cad350e4","choices":[{"index":0,"delta":{"role":"assistant","content":"","refusal":null},"logprobs":{"content":[],"refusal":null},"finish_reason":null}]}

data: {"id":"chatcmpl-Ayz7toKtZV6ZO6LnxkfNTvNp6lE8v","object":"chat.completion.chunk","created":1739098013,"model":"gpt-4o-2024-08-06","service_tier":"default","system_fingerprint":"fp_50cad350e4","choices":[{"index":0,"delta":{"content":"Sol"},"logprobs":{"content":[{"token":"Sol","logprob":-4.2846212,"bytes":[83,111,108],"top_logprobs":[{"token":"Ser","logprob":-0.53462136,"bytes":[83,101,114]},{"token":"Qu","logprob":-2.7846212,"bytes":[81,117]},{"token":"Ze","logprob":-2.7846212,"bytes":[90,101]},{"token":"Ep","logprob":-3.0346212,"bytes":[69,112]},{"token":"E","logprob":-3.5346212,"bytes":[69]}]}],"refusal":null},"finish_reason":null}]}

data: {"id":"chatcmpl-Ayz7toKtZV6ZO6LnxkfNTvNp6lE8v","object":"chat.completion.chunk","created":1739098013,"model":"gpt-4o-2024-08-06","service_tier":"default","system_fingerprint":"fp_50cad350e4","choices":[{"index":0,"delta":{},"logprobs":null,"finish_reason":"length"}]}

ok, Thanks for your reply