According tho Claude, The crash is clearly a bug in Xcode's built-in AI chat feature (IDEIntelligenceChat), not an authentication issue or anything on your end. What the crash log shows: The crash is happening in IDEIntelligenceChat — specifically in ChatInputEditorView.updateView and SourceEditorDataSource.ideChat_gracefullyApplyChangesToReflect. It's a SIGTRAP (assertion/precondition failure) triggered while SwiftUI is trying to lay out the AI chat panel. This is an Apple bug in Xcode 26.2 itself.
Xcode's built-in AI chat feature (IDEIntelligenceChat) crashes.
Xcode should never crash, so filing bug reports through Feedback Assistant are encouraged.