Calculate and analyze SaaS subscription metrics. Computes MRR, ARR, CAC, LTV, churn rate, Rule of 40, burn multiple, and other critical SaaS KPIs. Provides health assessment and benchmarks. Use when the user mentions SaaS metrics, MRR, ARR, churn, CAC, LTV, Rule of 40, unit economics, subscription analytics, burn multiple, NRR, net revenue retention, or magic number.