Evaluate extensibility patterns, abstraction layers, and configuration approaches in frameworks. Use when (1) assessing base class/protocol design, (2) understanding dependency injection patterns, (3) evaluating plugin/extension systems, (4) comparing code-first vs config-first approaches, or (5) determining framework flexibility for customization.

Generate a reference architecture specification from analyzed frameworks. Use when (1) designing a new agent framework based on prior art, (2) defining core primitives (Message, State, Tool types), (3) specifying interface protocols, (4) creating execution loop pseudocode, or (5) producing architecture diagrams and implementation roadmaps.