Asset inventories miss the paths that matter: the forgotten subdomain that shares a session store with production, the CI runner with cloud credentials, the internal API that trusts anything on the VPC. This guide shows how Sybil builds and maintains a living model of your stack — 29 domains, 851 subdomains, 3.2k open ports and counting — and how to use it to find the seams before someone else does. Pairs well with a continuous monitoring engagement, but useful standalone.