CodexA: capabilities, use cases, and sources

Developer Intelligence Engine — semantic code search, AI-assisted understanding, and workspace tooling Key features: Per-model vector subdirectories for multi-model index support, Vim -- Vimscript plugin with quickfix integration (Planned), Thread-safe SessionManager for concurrent AI agent sessions with TTL cleanup, Bridge session endpoints: /sessions, /sessions/create, /sessions/close, 39 CLI commands, 13 AI agent tools, 22 plugin hooks.