What the catalogue is

skills/ holds a compact set of Rust skills designed to be loaded one or two at a time. Each SKILL.md is intentionally short, with longer comparison material in references/. The router (rust-router) directs traffic so that callers do not load half the catalogue when one skill will do.

The tiers are:

• one router — rust-router,
• six language skills — memory and state, types and APIs, errors, async and concurrency, unsafe and FFI, performance and layout,
• six architecture and domain skills — crate design, supply chain, decision records, web services, CLIs and daemons, embedded and IoT,
• one verification router — rust-verification — and three deep dives, proptest, kani, and verus,
• three focused skills — rust-state-machines for logical state and transition design, rust-unit-testing for unit-test shape and assertions, and rust-unused-code for dead_code and unused_imports decisions,
• one migration skill — nll-to-polonius for adopting Polonius Alpha, retiring designs imposed by non-lexical lifetime (NLL) limitations, and evolving internal APIs towards borrow-centric forms.

For borrow-sensitive work, the router also establishes an ambient borrow-checker posture: nll, polonius-alpha, polonius-legacy, or unknown. That posture modifies the assumptions used by the ordinary language skills without loading a separate Polonius edition of each skill.