Spool provides a sidebar library of projects derived from working directories of multiple AI agents, with real-time session indexing that watches agent-specific storage paths and SQLite databases. It offers full-text search across the session archive with optional AI-synthesized answers, and includes a built-in scanner that detects leaked API keys, tokens, and PII across sessions with one-click rotation support for major vendors. An ACP-compatible /spool skill lets users pull relevant session fragments directly into active Claude Code conversations.