init-rust

Generate Rust tooling configuration files for a new project. This skill is used by the init-project skill but can also be used standalone.

Files to Generate

Copy assets/Cargo.toml into the target directory and substitute <project-or-subdirectory-name> with the actual project (or subdirectory) name. It ships pedantic clippy lints plus tuned dev/release profiles (thin debug info; LTO + codegen-units = 1 + strip + panic = "abort" for release). Profiles only take effect in a workspace-root manifest — if you're initialising a workspace member, move the two [profile.*] tables to the root Cargo.toml.
Copy assets/cargo-config.toml to .cargo/config.toml at the project (or workspace) root. It wires mold as the linker on Linux targets (see below). Skip this file for a workspace member — a single .cargo/config.toml at the root covers the whole workspace.

Build performance

These are the highest-leverage, low-effort speedups for Rust. The two levers are caching compilation (sccache) and faster linking (mold) — they're complementary: sccache skips recompiling unchanged crates, mold speeds up the link that happens even on a full cache hit.

Faster linking — mold (Linux only)

Shipped in assets/cargo-config.toml, scoped to x86_64/aarch64-unknown-linux-gnu. mold is ~3-10x faster than GNU ld on large dependency graphs, and linking is exactly what sccache can't cache. Contributors on Linux (and CI/Docker Linux stages) must install mold: apt-get install mold / dnf install mold / pacman -S mold.

macOS: deliberately not configured. mold cannot link Mach-O (its macOS port sold was discontinued), and Apple's default linker (ld-prime, Xcode 15+) is already fast. Do not set a global -fuse-ld=mold — it will break native macOS builds. If you want a faster-than-default linker on older macOS, lld (brew install llvm, then -fuse-ld=lld) is the option, but on current Xcode the default is fine.