rust-builder

name	rust-builder
description	Guide Rust implementation work with an explicit checklist for correctness, maintainability, and verification evidence. Use when writing, changing, or extending Rust code; implementing a bug fix or feature; or driving a disciplined builder role in a Rust workflow.

rust-builder

Purpose

Guide Rust implementation work with an explicit checklist that keeps behavior, maintainability, and verification evidence in scope.

When to use

Use this skill when you are writing, changing, or extending Rust code and need a disciplined implementation path instead of ad hoc edits.

Inputs expected

• task goal and intended user-visible behavior
• relevant files, modules, or crate boundaries
• current failing test, bug report, or verification target
• constraints such as public API stability, performance limits, or MSRV expectations

Build/implementation checklist

• define the smallest behavior change to make
• identify the crate, module, and API surface affected
• preserve ownership and borrowing clarity; prefer simple lifetimes over clever indirection, using The Rust Book and the Rust Reference when semantics need confirmation
• make error handling explicit and meaningful; avoid lossy unwrap or vague error text in production paths
• check public API stability before renaming types, functions, features, or error variants; review Rust API Guidelines expectations and note semver impact explicitly
• document concurrency assumptions for shared state, async work, or channel boundaries; include ordering, cancellation, and shared-state assumptions when they matter
• minimize unsafe; if unsafe is necessary, narrow the block and explain the invariant being protected at the point of use
• keep dependencies intentional; prefer standard library or existing crate patterns before adding new crates
• leave the code ready for the selected evidence profile, from minimal baseline through workspace or strict checks
• capture verification evidence before claiming completion, and record bootstrap blockers instead of silently weakening the profile

Expected outputs

• implementation aligned to the requested behavior
• updated or added tests when behavior changed
• concise note describing what changed, why, and which evidence profile was used
• explicit blockers or residual risks when verification is incomplete

Required evidence

• selected evidence profile command results:
  • minimal baseline: cargo fmt --check, cargo clippy -- -D warnings, cargo test, cargo audit
  • workspace baseline when applicable: cargo fmt --all -- --check, cargo clippy --workspace --all-targets --all-features -- -D warnings, cargo test --workspace --all-targets --all-features, cargo audit
• command output or concise summary for any environment blocker