This works by letting Codex trigger a Shortcut via an iMessage automation. The Shortcuts app has a full HTTP client so my iPhone can POST data back to my Mac.
Codex can also take actions by calling iOS deep links. One pattern I've found useful is having Codex grep search through iMessages on my Mac then open that specific message on my iPhone via a deep link.
This plugin is fully open source:
Siri sucks. So I made a way for Codex to act as my iPhone's voice assistant.
Now Codex can read my screen, control apps, and take actions on my behalf – all in vanilla iOS 27.