Explanation

Background knowledge and design rationale for protoPen's architecture and subsystems.

• Architecture -- System architecture: backends, subagents, tool layer, engagement lifecycle, observability.
• The Control Stack -- How goals, workflows, playbooks, subagents, and skills relate -- and when to reach for which.
• Knowledge Search -- Hybrid search with SQLite, sqlite-vec, FTS5, and Reciprocal Rank Fusion.
• Auto-Ingestion -- How tool output is automatically parsed and stored in the target intelligence database.
• Security Model -- Risk gating, guardrails, audit trail, Docker hardening, and alerting.