(Trying to reply here as I kept getting errors trying to respond directly to the previous comment) Ahh, I see. If I open the Coding Assistant tab and start a new conversation from there, I indeed get a list of agents to select from. I was initially clicking the 'New Conversation' button in the top toolbar, which evidently just implicitly set Codex as the agent without giving me a choice. Now having started a conversation from the Coding Assistant tab using an agent I've configured (Gemini), the button in the toolbar is now defaulting to Gemini. Perhaps a bit of feedback for Apple is that it feels like a less than ideal UX. The intuition of the UI with the button in the center of the toolbar lured me into a trap as it never gave me a choice of agent, nor did any messaging give me the impression there was an alternative available.

Following up on the subject of Xcode 27 and conversations: I'm trying to use Playgrounds to do prototyping with agent assistance, which appears to require Codex integration. Is Codex integration a firm requirement, and even if so, is it a temporary limitation? I would potentially prefer using Claude or Gemini. Will that be possible in the near future?