RUNEby Fable 5
Add a rune
cd /library

>inspect rust-masteryfound

Rust Mastery

Expert Rust where speed and safety reinforce each other — ownership, allocation discipline, profiling, fearless concurrency, disciplined unsafe.

Engineeringv1.0.0Claude Code · Codex
$ npx rune-add rust-mastery

No CLI to install — the rune is written straight into your agent's skills folder.

Overview

Rust Mastery loads Rust's founding bet into your agent: the safe code and the fast code are the same code. The doctrine has two reinforcing halves — don't fight the borrow checker, redesign until it agrees; and measure, then remove work. The core file carries fifteen non-negotiables and two decision frameworks (the ownership ladder and performance triage); nine reference files go deep on ownership and borrowing, type-driven design, error handling, the full optimization toolbox (profiles, allocation discipline, layout, SIMD, rayon), concurrency and async/tokio, disciplined unsafe with Miri, crate API design, testing, and decoding compiler errors — loaded only when the task needs them.

What it grants

  • 01The ownership ladder: restructure > borrow > deliberate clone > Rc/Arc > unsafe — with the fight catalog for each borrow-checker classic
  • 02Performance triage in order of leverage: release profiles, algorithms, allocations, copies, contention, rayon, micro
  • 03Allocation discipline: with_capacity, buffer reuse, iterator fusion, arenas, small-vec — the everyday wins
  • 04Profiling as doctrine: criterion, flamegraphs, dhat, hyperfine — no optimization without a before/after in --release
  • 05Type-driven design: illegal states unrepresentable, newtypes, typestate, generics vs dyn dispatch decided by data
  • 06Errors as API: thiserror for libraries, anyhow for apps, panic policy, matchable variants
  • 07Fearless concurrency with discipline: locks never held across .await, cancellation-aware async, rayon vs tokio by workload
  • 08unsafe as a contract: SAFETY comments, safe wrappers, the UB catalog, Miri and fuzzing in CI, FFI mechanics
  • 09Crate craft: API signatures that borrow, additive features, semver discipline, doc tests on every public item
  • 10Compiler-error decoder ring: E0382/E0502/'not Send' surgically fixed, plus build-speed and footgun checklists

Try it like this

rune@fable5:~

agent> Profile and fix this hot path the rust-mastery way — release build, kill the allocations, justify every clone, and prove the wins with criterion.