Remove the devShells.default — nix fmt already provides swift-format via treefmt, and nix build handles production builds. The dev shell added no value beyond what these commands already provide.
Document doCheck = false: SwiftPM's swift-test requires
xcrun --find xctest which needs Xcode, and corelibs-xctest in nix
only provides the library, not the runner. No Swift package in nixpkgs
has solved this — tests require Xcode: swift test
AI-assisted: GitLab Duo Agentic Chat (Claude Sonnet 4)