What problem does it solve? Specs drift from shipped code and structures grow without backing. This Skill derives or updates ARCHITECTURE.md from a proven PRODUCT_SPEC.md so every spec fact has exactly one owning node, every node pins to real file:line locations, and quality budgets carry measurable numbers. ## Core Features & Use Cases - Node structure derivation: Proposes named nodes and seams based on the project's kind (fullstack app, backend service, CLI, skill pack, content project), then lets the spec's facts decide the final map. - Reality pinning and budgets: Reconciles every node with shipped code via grep-verified file:line pins, and writes quality budgets with instrumentation homes and watchers. - Runtime, placement, and fitness views: Walks every promised flow through the nodes, states where each node runs and where secrets live, and applies a three-question fitness test to every new or carved node. - Use Case: Hand the Skill a proven spec for a fullstack app and receive an updated ARCHITECTURE.md with frontend, backend, and store nodes, named seams, a generated Reference table, and a coverage rule ensuring no orphan spec facts. ## Quick Start Use the architect skill to derive ARCHITECTURE.md from my proven PRODUCT_SPEC.md and pin every node to the shipped code.