Getting Gemini 3.5 or 3.6 Flash to work with Xcode 27 Beta

I've been trying for months to get Gemini 3.5 Flash to work with Xcode 27 Beta (1-3) agentic coding but have failed. Xcode currently uses Gemini CLI v0.42.0 from last year, so it can't call Gemini 3.5 Flash even though all that needs to change is a few characters in the API call.

Gemini users are currently forced to choose between 3.1 Pro and 3.1 Flash Preview--both weren't the best choices two months ago, but with the release of 3.6 Flash which is better at coding that 3.1 Pro and miles cheaper, these choices are now unsuitable for any serious workload.

I live in Hong Kong, where OpenAI and Anthropic services aren't offered, so Google is the only (native) AI provider for Xcode agentic coding. The cost issue from funneling all the work into 3.1 Pro is terrible especially with some agent bugs that have yet to be ironed out.

Given Apple's close partnership with Google on AI, I'm genuinely surprised that after 4 Betas we're still using a Gemini CLI from 2025 that forces users to choose between two very unappealing models. Xcode is basically forcing Google users to switch to OpenAI/Anthropic.


Questions:

  1. I'd like to know if this will be fixed soon and whether Google users should expect slower updates (i.e. be forced to use older models).

  2. Does anyone know of any workarounds?

Answered by Developer Tools Engineer in 898609022

Thanks for using our intelligence features in Xcode!

We are constantly working to validate and update our partner agent binaries, and we have nothing to report about future plans at this moment, but we are unlikely to stay at any single version for too much longer.

One thing worth noting about Gemini in particular is that because these binaries are built specifically for Xcode, their version numbering may not align with public versions built and shipped for other purposes, even though they may sometimes contain the features you are looking for anyway.

Xcode currently uses Gemini CLI v0.42.0 from last year

Correction: 0.42.0 was released in May

Things move so fast in the AI world, May feels like last year.

Thanks for using our intelligence features in Xcode!

We are constantly working to validate and update our partner agent binaries, and we have nothing to report about future plans at this moment, but we are unlikely to stay at any single version for too much longer.

One thing worth noting about Gemini in particular is that because these binaries are built specifically for Xcode, their version numbering may not align with public versions built and shipped for other purposes, even though they may sometimes contain the features you are looking for anyway.

Update: Xcode 27 Beta 5 works with Gemini 3.5 Flash

I did some digging around and it turns out the very latest weekly Gemini CLI build doesn't work with 3.6 Flash, weeks after its release^, so Apple can't really be blamed for this. Google is being so slow with everything it makes me want to jump ship to OpenAI/Anthropic even though they're not available where I live.

As a side note, Gemini 3.6 Flash (extended) leading me in circles with frequent and persistent hallucinations about various Google products like Antigravity and Gemini CLI doesn't inspire confidence.

While I'm here I'd like to request the ability to specify service/pricing tier (standard/flex/batch/priority)--this setting can greatly impact cost


^ I've avoided installing Gemini CLI and using it as an external ACP agent due to security and privacy concerns but used a VM to check it out

Google released 3.7 Flash just yesterday

They also slashed prices for 3.7 and 3.6 Flash by 50%!

What's relevant to us is they didn't slash prices for 3.5 Flash, so Xcode agentic coding users are stuck with a service that's double the price for less performance (it gets worse if you use 3.1 Pro Preview).

The more I look into gemini-cli(which Xcode's native agentic coding is dependent on, as Antigravity doesn't support ACP), the more dire things look for Gemini users who want to stay in Xcode.

https://github.com/google-gemini/gemini-cli/discussions/28685

https://github.com/google-gemini/gemini-cli/issues/28625

https://github.com/google-gemini/gemini-cli/issues/28802

There are signs that, despite explicitly committing to supporting Gemini CLI for enterprise users (which ostensibly includes Apple and downstream Xcode users), Google has effectively put Gemini CLI on ice, rolling out support for 3.5 Flash only after 3.6 Flash was released, and immediately before 3.7 Flash.

An issue to add 3.6 and 3.7 support was flagged as "Backlog - a good idea but not currently a priority."

It feels like they're trying to soft-force everyone into using Antigravity, but for many reasons I'd much rather stick with Xcode.

The Coding Intelligence team at Apple should really look into alternative/custom ACP agent solutions, at least for Gemini, or just drop native Gemini agent support altogether. Otherwise a lot of devs might wrongly think it's Apple's fault they're forced to use older, less performant models at double price.

Getting Gemini 3.5 or 3.6 Flash to work with Xcode 27 Beta
 
 
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