rust-impl-cargo-project

The single-crate Cargo project setup skill: how to scaffold a crate, structure its Cargo.toml, declare dependencies safely, design features that obey the additive principle, tune profiles, override third-party code with [patch] / [replace], configure package-level lints via the [lints] table, and opt into the MSRV-aware resolver introduced in Rust 1.84.

Cross-references: [[rust-impl-workspaces]] (multi-crate layout with [workspace]), [[rust-core-toolchain]] (rustup channels, components, rust-toolchain.toml), [[rust-core-language-versions]] (which features stabilized in which release), [[rust-impl-build-scripts]] (build.rs, OUT_DIR, cargo:: directives).

When to use this skill

• User runs cargo new or cargo init and asks lib vs bin, what edition, where files go.
• User edits Cargo.toml and asks about [package], [dependencies], [dev-dependencies], [build-dependencies], or target-specific dependencies.
• User asks about version requirements: caret vs tilde vs exact vs wildcard.
• User designs a feature flag, hits a non-additive design, or asks about dep: / ? syntax.
• User tunes [profile.release], defines a custom profile, or asks about LTO, opt-level, codegen-units, strip, panic.
• User wants to override a transitive dependency via [patch.crates-io] or [replace].
• User wants project-wide lint configuration via the [lints] table.
• User wants cargo add to pick versions compatible with their MSRV (Rust 1.84+ resolver).