The Xcode 26 System Prompts collection contains a couple of chat templates, but more interestingly: typical LLM-targeted documentation of new-ish technology to prime their context for stuff that’s not well-represented in training data.

For example, ever wondered when to use the new InlineArray? See Swift-InlineArray-Span.md

When to Use InlineArray

InlineArray is ideal for:

• Performance-critical code paths
• Fixed-size collections that never change size
• Avoiding heap allocations and reference counting overhead
• Collections that are modified in place but rarely copied
• Embedded systems or low-level programming

Not suitable for:

• Collections that need to grow or shrink
• Collections that benefit from copy-on-write semantics
• Collections that are frequently copied or shared between variables

That is a very good summary that is painfully absent on the InlineArray API docs. As a Swift veteran, you usually look for a Swift Evolution proposal for the new tech then an try to find out there what this is all about.

Which is to say: I don’t mind quick summaries for busy developers like these!

The collection also has docs for 3D charts, VisualIntelligence (I didn’t know that framework existed!), and UIKit Liquid Glass guides and AttributedString tutorials.

These documents are probably not written by a human, or team of humans, because of inconsistent tone and all. So I’d wager they were LLM-generated themselves. I do hope they were edited for misinformation at least!

If you use agentic coding tools, it’s sensible to copy Apple’s docs into your setup. For Claude Code, you’d drop these into a docs/ folder somewhere to look up, but then you need an index to tell Claude to look there. Per project, that can get repetitive, and as a global setting, it can pollute your context. So maybe a clever solution would be to use ‘formalized’ Skills like Antoine van der Lee’s SwiftUI Expert Skill that is available in Claude Code as a plugin to bundle everything.

Thanks Joachim for sharing the link on Mastodon!