Pull Request Type

• ✨ feat
• 🐛 fix
• ♻️ refactor
• 💄 style
• 🔨 chore
• 📝 docs

Relevant Issues

resolves #4465

What is in this change?

Migrate OpenAI aibitat provider to use the Responses API from the OpenAI SDK. This allows us to easily support both past and future models through a unified API so now you can use agents for gpt-5 and the o-* models as well as the previous models that have already been launched.

Additional Information

Due to the unique flow by the responses API:

• OpenAI provider now has its own stream and complete functions on its class to override the inherited Provider which still will use completions (for unification of interface among all other LLM providers)
• Required us to add originalFunctionCall to the stream and non-stream handler for the main aibitat class so that we can consistently rebuild the function call post-execution since the message history must have a matching function_call and function_call_output in the messages array in order to be valid.

Developer Validations

• I ran yarn lint from the root of the repo & committed changes
• Relevant documentation has been updated
• I have tested my code functionality
• Docker build succeeds locally

Additional QA

• Test new models (gpt-5, o-*, etc)
• Test older gen models like 3.5
• Test with and without tools available
• Test with streaming disabled (manually) to force complete to run
• Test with followup messages, multiple tool calls, etc.
• Test existing providers for spot check for changes introduced to the aibitat handlers.