Yeah I've looked into that kind of thing. In general I don't love the pattern where a coding agent calls another agent automatically. It's hard to control and I don't like how the session "disappears" after the call is done. It can be useful to leave that Codex window open for one more question.
One tool that solves this is RepoPrompt MCP. You can have Sonnet 4.5 set up a call to GPT-5-Pro via API and then that session stays persisted in another window for you to interact with, branch, etc.
One tool that solves this is RepoPrompt MCP. You can have Sonnet 4.5 set up a call to GPT-5-Pro via API and then that session stays persisted in another window for you to interact with, branch, etc.