Sem, from Ataraxy Labs, layers semantic understanding over any git repository with no config or plugins. Where git diff reports changed lines, sem diff reports changed entities: this function added, that one modified, a legacy one deleted. Six commands cover diff, blame, impact, log, entities and context across 26 languages, with typical diffs computed in 8 milliseconds and JSON output on every command.
Two of those commands aim squarely at agents. Sem impact walks the cross-file dependency graph to report everything a change touches, tests included. Sem context builds a token-budgeted prompt window containing an entity, its dependencies and its dependents, sized to fit a model's context limit. Ataraxy's headline benchmark, self-published and worth that caveat, claims agents are 2.3 times more accurate when given sem output instead of raw line diffs.
The interesting signal is not the number. It is that developer tools have started designing their output for machine readers first, with humans as the secondary audience.