Add support for max_completion_tokens in AzureOpenAiChatOptions

[iAMSagar44]

Support for max_completion_tokens was introduced in ChatCompletionsOptions class (Azure SDK for Java - package com.azure.ai.openai.models) last year.

Reference - Azure/azure-sdk-for-java#43037

The maxTokens value is now deprecated in favor of max_completion_tokens, and is not compatible with o1 series models.

Reference - https://learn.microsoft.com/en-us/java/api/com.azure.ai.openai.models.chatcompletionsoptions?view=azure-java-preview#com-azure-ai-openai-models-chatcompletionsoptions-setmaxtokens(java-lang-integer)

[iAMSagar44]

I have submitted a pull request for this change - #3305

[ChoHadam]

Hi @iAMSagar44 !

Thank you for raising this important issue. I've been working on an implementation
that addresses @markpollack's feedback from PR #3305 about avoiding breaking changes.

My approach:

• Keeps all existing maxTokens methods (no breaking changes)
• Adds maxCompletionTokens as a separate, independent field
• Both options can coexist - users choose based on their model type
• Includes comprehensive unit tests

The key difference is that we don't need to deprecate or remove maxTokens -
both parameters serve different purposes:

• maxTokens for standard models
• maxCompletionTokens for reasoning models (o1, o3, etc.)

Would you like to review my implementation? I can open a PR that addresses
the maintainer's concerns while preserving your original intent.

Thanks again for identifying this need!

[Hiosdra]

Hi, for services using Spring AI, using GPT-5 is blocked by this issue and further work on previous PR didn't happen, I created a new PR - #4177
I would be grateful for someone to look at it. If any further changes are needed, I'm willing to make them as a microservice in my company is waiting for this issue to be resolved.