Apple just released Xcode 26.3 RC. If you think it’s just another .x release needed to align with the upcoming release of MacOS 26.3, think again! Coding Intelligence in Xcode 26.3 take a huge leap forward, with robust support for agentic coding. Out of the box, there’s built in support for Claude and Codex, but those require paid plans, and token efficiency is unclear right now, particularly with a release candidate.

Want to explore these new features without spending more? You can, thanks to the ability to add other agents, including those with generous free tiers. Let’s look at how we can integrate Google Gemini into this new version of Xcode.

Google Gemini offers a generous free tier, but support for Gemini isn’t preconfigured in Xcode 26.3, at least not as of Xcode 26.3 RC. Adding it isn’t difficult, but you’ll need a few things first:

• A Google account
• Access to Google AI Studio
• A Gemini API key

If you don’t have a Google account, create one at https://accounts.google.com/.

Go to aistudio.google.com and sign in with your Google account.

Accept the Generative AI Terms of Service.

Don’t upgrade to a paid plan. You’ll be using the free one.

On the bottom left of the window, click “Get API key”

On the top right of the window, click “Create API key”

Click on your API key to see the details, then click the copy icon next to your key to copy it.

You now have everything you need to set up Xcode. Here’s how:

Open Xcode 26.3 RC or later.

Go to Settings and select Intelligence.

Click Add a Provider…

You’ll see a dialog like this…

For the URL, enter https://generativelanguage.googleapis.com/v1beta/openai

For the API key, enter the word “Bearer” followed by a space, then paste in your copied API key.

For the API Key Header, type “Authorization”

Click Add. You should see Googleapis listed under Providers.

You’re good to go, but I’d recommend one more step. 

Let’s add an Agents.md file that Gemini and your other agents can follow. There are three options:

Method 1: The Root Directory Strategy (Recommended)

Xcode's coding intelligence is designed to automatically scan for context files in your project.

1. Ensure your Agents.md file is located in the root directory of your Xcode project (where your .xcodeproj or .xcworkspace file is).
2. Rename it (if needed): While some agents look for Agents.md, the most reliable filename for the Gemini-specific integration in many environments is GEMINI.md.
3. Once the file is in the root, Gemini will automatically ingest it as a "preamble" to every request you make within that project.

Method 2: Reference it via the "Context Drawer"

If you prefer to keep the filename as Agents.md, you can manually attach it to your session:

1. Open the Coding Assistant panel (the star icon in the top right or Cmd+Shift+A).
2. Look for the Context icon (often looks like a paperclip or a drawer) at the bottom of the chat interface.
3. Select "Add File" and choose your Agents.md.
4. This explicitly feeds the contents of that file into Gemini’s context window for the current conversation.

Method 3: The Library Config Folder (Global Context)

If your Agents.md contains rules you want Gemini to follow across all Xcode projects (like your personal coding style or favorite libraries), you can place a copy in Xcode's global configuration directory for agents:

• Path: ~/Library/Developer/Xcode/CodingAssistant/CustomAgents/
• Note: You may need to create the CustomAgents folder if it doesn't exist yet.

Gemini models may not be the most robust agents for SwiftUI development, especially when it comes to front-end design, but they’re a great way to get your feet wet with the impressive new coding intelligence features without burning through costly tokens.