This triggers automatically on Rust ownership errors like E0382 or E0597 and pushes you to ask design questions before reaching for clone(). Instead of just fixing the compiler error, it maps each error code to a fundamental question: who should own this data, is the scope boundary right, should mutation happen elsewhere. The trace up/trace down framework is smart, connecting ownership issues to domain modeling (m09) or resource patterns (m02) when quick fixes fail three times. Best part is the error-to-design-question table that reframes "borrowed value does not live long enough" as "is the scope boundary correct?" It won't teach you ownership from scratch, but it will stop you from cargo cult cloning everything.
npx skills add https://github.com/actionbook/rust-skills --skill m01-ownership