What problem does it solve? macOS SwiftUI apps accumulate rendering anti-patterns—formatters allocated inside body, identity churn from .id(UUID()), AnyView type-erasure, greedy GeometryReader, and per-render filter/sort in ForEach—that cause needless re-renders, especially in resizable, long-lived Mac windows. This Skill locates those defects with a hybrid lint engine, verifies them against real shipping-app code and Apple docs, and fixes the mechanical ones safely. ## Core Features & Use Cases - 12-rule defect index (vperf-01 to vperf-12): Detects heavyweight allocations in body/init, identity churn, un-skippable children, high-frequency @Environment fan-out, over-broad @Observable reads, eager ForEach, and leftover Self.printChanges() debug lines. - Hybrid lint engine: Runs tier-1 grep tells plus tier-2 ast-grep structural rules (formatter-inside-body, logic-in-init) with a per-file parse probe, emitting unified JSON and SARIF output. - Grounded fixes: Every suggested correction is backed by a consensus call shape from 1,857 real macOS apps via the swiftui-ctx CLI, plus Apple documentation fetched through Sosumi, with findings written to a unified on-disk schema. - Use Case: Point it at an in-progress macOS SwiftUI project; it locates a DateFormatter built inside body, confirms the Text(:format:) fix target against the deployment target, and writes a permalinked finding with the correct pattern. ## Quick Start Ask the agent to audit your macOS SwiftUI project's view performance and report findings with fixes.
