OpenAI Responses API support

[mastraus]

The OpenAI Chat Completions API currently supports two models for web search, gpt-4o-search-preview and gpt-4o-mini-search-preview. However, neither of these models support function calling (see OpenAI documentation here and here; notice Features is empty for both.)

It would be great to use web search in addition to functions/tools. It looks like we will need to use the OpenAI Responses API to achieve this capability.

[crmne]

@mastraus the Responses API is a major endeavor. I think @tpaulshippy is working on this. Feel free to sync and open a PR about it.

[tpaulshippy]

Yeah @mastraus and I are coworkers.

I took another look this evening at making a PR for the responses API and I'm wondering if we need to have a mode of the OpenAI provider for it that you could either opt into or would get automatically enabled when you use a feature like web search that requires it. There are quite a few differences with it and switching to it outright breaks all the other OpenAI compatible providers like OpenRouter, DeepSeek, Ollama, etc.

[tpaulshippy]

Since audio is the only thing not supported yet, I'm back to thinking we switch to responses outright. We can just leave the other code in for compatibility with other providers (maybe move it to a separate spot).

[crmne]

I'm back to thinking we switch to responses outright.

@tpaulshippy no. The Chat Completion API is still largely supported and compatible even with OpenAI compatible APIs. Only few things are exclusive to the Responses API. It's a huge undertaking with very little reward at the moment.

[tpaulshippy]

It wasn't that huge...

[bricolage]

Hey! I'll upvote this one, I would love to make requests that use OpenAI's web search without having to use ruby-openai directly.