Sem: New primitive for code understanding – not LSPs, but entities on top of Git

Sem is a new command-line tool that provides semantic, entity-level code understanding on top of Git by analyzing functions, classes, and methods rather than individual lines. It offers six core commands—diff, blame, impact, log, entities, and context—that work across 26 languages without configuration, and AI agents using sem output are 2.3x more accurate than those using raw diffs. The tool integrates directly with Git and can be installed via a single command, automatically replacing standard git diff output with semantic analysis.