Status: IN
Observer's composition architecture is principally grounded through two independent mechanisms: SRP's actor-based framing provides the principled decision criterion for when to compose Observer with Mediator (via ChangeManager centralizing notifications when actors are entangled), while Observer's built-in Template Method integration ensures compositional safety by enforcing state self-consistency before notification dispatch.
Observer's designed-for-composition architecture + SRP's principled composition decision = principled composition architecture
Depends on (SL): observer-designed-for-pattern-composition, srp-grounds-observer-mediator-decision