> Claude 4.5 Sonnet definitely struggles with Swift 6.2 Concurrency semantics and has several times gotten itself stuck rather badly.

What solved that for me was to leverage the for-LLM docs Apple ships with Xcode, and then build a swift6-concurrency skill. Here's an example script to copy the Xcode docs into your repo: https://gist.github.com/CharlesWiltgen/75583f53114d1f2f5bae3...