SETools is a comprehensive SELinux policy analysis toolkit providing both command-line and GUI utilities for querying, comparing, and analyzing SELinux policies. The system consists of a core library (setools) for policy representation and analysis, GUI components (setoolsgui) for interactive analysis via apol, and specialized tools like seinfo (policy querying), sesearch (rule search), sediff (policy comparison), and setools-mcp (MCP server for LLM integration). The architecture features a modular design with clear separation between policy representation, querying mechanisms, difference analysis, and validation frameworks. Key strengths include a reusable query framework using descriptor patterns and mixins, a robust difference engine with wrapper-based caching, and a well-structured GUI following model-view patterns. The project demonstrates active maintenance with recent updates, strict dependency management, and extensive test coverage.