What problem does it solve? Engineers working on the Sonder Runtime need to know why the code is structured the way it is, which documents are authoritative, and which invariants are machine-enforced before making structural changes. This Skill answers architecture questions without requiring a full read of the ADRs, the master spec, and the 641-line check_architecture.py script. ## Core Features & Use Cases - Document authority hierarchy: Ranks the master implementation spec, focused contract docs, verified evidence, and historical planning docs so rank-4 documents are never cited as current status. - ADR and invariant reference: Summarizes the six SPEC-5 ADRs, the layered package dependency rule, and the ratchets enforced by scripts/check_architecture.py, including retired-module and shim policies. - Violation triage and weak points: Maps check_architecture.py violation messages to the correct fix and lists known-weak points such as the 25,325-line server.py composition root. - Use Case: When check_architecture.py fails with "production caller imports compatibility root module", consult this Skill to learn the right fix is importing the packaged sonder_runtime adapter instead of adding an exception. ## Quick Start Ask why the Sonder Runtime code is structured this way or what invariant a proposed import change would break.
