Steve Troughton-Smith

The RC 2 version of Xcode 26.3 does indeed distribute a new version of Codex that enables the gpt-5.3-codex model.

I would guess that's why they waited before publishing 26.3 to the App Store, and it also answers the question as to how their model update strategy might play out

Feb 20 at 7:09pmIvory for Mac
Show threadDave ReedFeb 20
@stroughtonsmith does copying the codex or claude executable you can update via brew etc. into the appropriate subdirectory in -/Library/Developer/Xcode/CodingAssistant not allow you to update w/o an Xcode release. I thought I heard it did.
Show threadEytan SchulmanFeb 21

@davereed @stroughtonsmith Yes it does. Not sure about the way brew installs, I installed via Anthropic’s native Claude Code installer.

Running

cp `which claude` ~/Library/Developer/Xcode/CodingAssistant/Agents/Versions/26.3/claude

Gave me Opus 4.6 in Xcode 26.3, which it didn't do beforehand..

Show threadDarrenFeb 21
@stroughtonsmith @davereed yea it does 🙌🏼
I’ve never been able to get it working on an Intel Mac as Xcode downloads the Apple Silicon binary of codex. I’ve managed to copy the Universal codex into Xcode and now have it working. Thanks for the tip.
Show threadSaeed TaheriFeb 27
@venderbase By doing this, the intelligence section of Xcode settings and the agentic feature gets enabled on Intel Macs you say?!
Show threadDarrenFeb 28
@sdtaheri the section was always enabled, it just didn’t work.
You have to have the latest macOS for the intelligent section to appear.
Show threadAwaxFeb 20

@stroughtonsmith I think codex 5.3 has the new response interaction tool (prompting the user to pick a choice) that requires the agent to actually expose such tool. Might also be reason for delaying until RC2 and tool availability.

This has been discussed as part of OpenCode adoption of Codex5.3. Might be similar for Xcode

Show threadJoachim BondoFeb 22
@stroughtonsmith Good to know. Unfortunately, RC 2 ships with clang 17, where Xcode 26.4 beta ships with clang 21. But what I really need is clang 22 (that supports `defer` in C ;-).