- Propagate serialization errors in output path instead of unwrap_or_default() silently writing blank lines (main.rs, handler.rs). - Cap selection undo stack at 50 entries to bound memory on heavy multi-select usage (menu.rs). - Break TUI event loop on dead action channel instead of silently dropping keypresses (lib.rs). - Log dropped handler hook events when channel is full (handler.rs). - Reject menu and headless DSL tests that have no assertions at compile time (codegen.rs). - Document filter_text ownership design in TUI and exec/handler error asymmetry in CompositeHandler.