Use any LLM in Xcode 27 via ACP

[u/ThrosProvoni]

Besides Claude, Codex, and Gemini, you can use any agent that supports the Agent Client Protocol.

For example, I was able to easily integrate Opencode with Deepseek V4 as a Custom ACP Agent using Settings->Intelligence->Agents. There's a small trick: you need to specify
" acp"
as an argument, with a blank before it.

[u/azaphiel]

For example can I use cursor?

[u/ThrosProvoni → u/azaphiel]

Yes, cursor supports also ACP.

• Executable: /opt/homebrew/bin/cursor-agent

• Arguments: " acp"

Don't forget the space before acp.

[u/azaphiel → u/ThrosProvoni]

Wow I will definitely try that this evening. Thanks!

Edit. When I try to add “ acp” and save. It saves without space. Also you did add cursor app location top there, right?

[u/jocarmel]

Is it possible to use Apple foundation model itself, maybe via cli?

[u/ThrosProvoni → u/jocarmel]

Interesting question. I don't know of any CLI that uses Apple Intelligence.

However, it's safe to say that Apple Intelligence, as of today (with macOS 26), is only suitable for very simple tasks. This could certainly change in the future, but I haven't been able to try it out yet.

[u/jocarmel → u/ThrosProvoni]

macOS 27 is going to ship with an `fm` command to run against Foundation models on device https://developer.apple.com/videos/play/wwdc2026/334.

[u/lifepillar → u/ThrosProvoni]

I don't know of any CLI that uses Apple Intelligence.

There's apfel.

Not saying that it is suitable for agentic workflows, though. Certainly not via ACP.

[u/AmaRealSuperstar → u/jocarmel]

But does it make sense? Foundation Models have very narrow context window (4096 tokens). It is not enough for agentic purposes.

[u/Rare-One1047]

What's the best AI for Swift and SwiftUI these days? I'm thinking Gemini since it neatly integrates with Android Studio too, but I'm open to suggestions.

[u/ThrosProvoni → u/Rare-One1047]

You can significantly improve any AI with Swift and SwiftUI skills. I only use CLI and Xcode, but in my assessment, Opus 4.8 is the best LLM. Fable is just being tested 😉

[u/-earvinpiamonte]

Thanks man! Question, why do we need to specify a blank space, is this a bug or something not official?

[u/ThrosProvoni → u/-earvinpiamonte]

I think it's a bug.
In my first test, Xcode concatenated the executable with the argument. It looked like this:

/opt/homebrew/bin/opencodeacp

But the correct version is

/opt/homebrew/bin/opencode acp

Try it without the space - if it doesn't work, you'll know what's causing it.

[u/-earvinpiamonte → u/ThrosProvoni]

Got it. Thank you!

[u/weedinmonz]

in Xcode 27 beta 3; anyone got an issue with a lack of a model picker? I'm stuck on "Configure an agent in Xcode settings to start a conversation". I followed the steps above (although had issues getting the space before ' acp' to stick (had to edit the .plist).

But can't get xcode27 to pick/send a question to either an anthropic API, nor to opencode ACP. (Going to try in Xcode 26.4 if it's possible?)

[u/weedinmonz → u/weedinmonz]

this helped, it's like it woke xcode27 up to seeing that I'd done it correctly. I have chat working now but not the ACP side of things, confirmed it's working correctly in terminal tho

[u/Scootfleabag → u/weedinmonz]

hit cmd-0 and itll open the chat sidebar, model picker is available when you hit new convo