Rust Expert
Use this as the default Rust engineering router. Inspect the repo first, load
only the references needed for the task, then use compiler/test feedback as
design evidence.
Operating Model
- Read the local guidance and manifests first:
AGENTS.md, Cargo.toml,
Cargo.lock, rust-toolchain.toml, .cargo/config.toml, CI, justfile,
mise.toml, and nearby tests.
- Classify the task before editing: compile failure, implementation, review,
refactor, dependency, public API, release, performance, or security.
- Fix the root cause. Avoid silencing Rust with reflexive
.clone(),
Arc<Mutex<_>>, broad trait bounds, unwrap, or unsafe.
- Use repo-native gates first. When command surface is unclear, run
scripts/discover-rust-gates.mjs <repo-root>.
- Research current docs/source when facts can drift: dependency additions or
upgrades, version-sensitive APIs, Tauri/plugin support, public API/release
decisions, security, unsafe/FFI, or novel crates.
Domain Routing
| Signal |
Prefer |
| Command-line app, subcommands, flags, config precedence, JSON/stdout contracts |
rust-cli-clap |
| Terminal UI, interactive dashboards, Ratatui widgets/layout/events |
rust-tui-ratatui |
Tauri v2, src-tauri, commands, capabilities, IPC, updater, mobile layout |
rust-tauri-apps |
| HTTP APIs/services, Axum, Tower, Tokio server runtime, DB pools |
rust-web-services |
| Broad architecture review or multi-domain Rust planning explicitly requested |
rust-mega-eng |
If no specialist owns the task, stay in rust-expert. Keep rust-mega-eng
explicit-only; broad wording alone does not trigger it.
Reference Map
Load the smallest needed set:
references/toolchain-cargo.md: editions, MSRV, resolver, lockfiles, features,
workspace policy, verification commands.references/ownership-async-errors.md: borrow checker, ownership,
lifetimes, async Send, task ownership, typed errors.references/crate-selection.md: preferred crates, dependency decision rules,
feature hygiene, source-refresh triggers.references/testing-quality.md: unit/integration/doctest/property/snapshot/
benchmark checks and reviewable test design.references/performance-security.md: measurement, allocations, unsafe/FFI,
supply chain, cargo-deny/audit, secrets and subprocesses.
Toolchain Policy
Existing repos: preserve detected contracts first. Do not change edition,
resolver, rust-version, lockfile policy, or exact toolchain pins unless the
task is explicitly a migration or the repo is missing required metadata.
Greenfield defaults:
edition = "2024".- Set
[workspace] resolver = "3" explicitly for virtual workspaces.
- Add an explicit
rust-version and document the policy.
- Commit
Cargo.lock by default; for public libraries, also test latest
dependency resolution because consumers use Cargo.toml.
- Avoid exact
rust-toolchain.toml version pins unless reproducibility,
nightly, embedded/custom targets, or release policy requires them.
Verification Ladder
Start narrow, then broaden:
cargo check -p <crate>
cargo test -p <crate> <test_name>
cargo fmt --all -- --check
cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
cargo test --workspace --all-targets --all-features --locked
cargo test --doc --workspace --locked
Use cargo nextest run when configured. Add cargo hack, cargo deny,
cargo audit, cargo semver-checks, or release tooling only when the repo or
change surface warrants it.
Helper Scripts
scripts/discover-rust-gates.mjs [repo-root]: print likely Rust gates.scripts/check-reference-links.mjs <skill-dir...>: validate local skill links.scripts/check-trigger-evals.mjs <skill-dir...>: validate trigger eval JSON.
1---2name: rust-expert3description: Core Rust engineering. Use for implementation, debugging, review, compiler errors, ownership and lifetimes, traits and generics, async and concurrency, typed errors, Cargo and MSRV, crate choice, tests, performance, unsafe and security. Excludes focused product surfaces owned by narrower Rust skills.4---56# Rust Expert78Use this as the default Rust engineering router. Inspect the repo first, load9only the references needed for the task, then use compiler/test feedback as10design evidence.1112## Operating Model13141. Read the local guidance and manifests first: `AGENTS.md`, `Cargo.toml`,15 `Cargo.lock`, `rust-toolchain.toml`, `.cargo/config.toml`, CI, `justfile`,16 `mise.toml`, and nearby tests.172. Classify the task before editing: compile failure, implementation, review,18 refactor, dependency, public API, release, performance, or security.193. Fix the root cause. Avoid silencing Rust with reflexive `.clone()`,20 `Arc<Mutex<_>>`, broad trait bounds, `unwrap`, or `unsafe`.214. Use repo-native gates first. When command surface is unclear, run22 `scripts/discover-rust-gates.mjs <repo-root>`.235. Research current docs/source when facts can drift: dependency additions or24 upgrades, version-sensitive APIs, Tauri/plugin support, public API/release25 decisions, security, unsafe/FFI, or novel crates.2627## Domain Routing2829| Signal | Prefer |30| --- | --- |31| Command-line app, subcommands, flags, config precedence, JSON/stdout contracts | `rust-cli-clap` |32| Terminal UI, interactive dashboards, Ratatui widgets/layout/events | `rust-tui-ratatui` |33| Tauri v2, `src-tauri`, commands, capabilities, IPC, updater, mobile layout | `rust-tauri-apps` |34| HTTP APIs/services, Axum, Tower, Tokio server runtime, DB pools | `rust-web-services` |35| Broad architecture review or multi-domain Rust planning explicitly requested | `rust-mega-eng` |3637If no specialist owns the task, stay in `rust-expert`. Keep `rust-mega-eng`38explicit-only; broad wording alone does not trigger it.3940## Reference Map4142Load the smallest needed set:4344- `references/toolchain-cargo.md`: editions, MSRV, resolver, lockfiles, features,45 workspace policy, verification commands.46- `references/ownership-async-errors.md`: borrow checker, ownership,47 lifetimes, async `Send`, task ownership, typed errors.48- `references/crate-selection.md`: preferred crates, dependency decision rules,49 feature hygiene, source-refresh triggers.50- `references/testing-quality.md`: unit/integration/doctest/property/snapshot/51 benchmark checks and reviewable test design.52- `references/performance-security.md`: measurement, allocations, unsafe/FFI,53 supply chain, cargo-deny/audit, secrets and subprocesses.5455## Toolchain Policy5657Existing repos: preserve detected contracts first. Do not change edition,58resolver, `rust-version`, lockfile policy, or exact toolchain pins unless the59task is explicitly a migration or the repo is missing required metadata.6061Greenfield defaults:6263- `edition = "2024"`.64- Set `[workspace] resolver = "3"` explicitly for virtual workspaces.65- Add an explicit `rust-version` and document the policy.66- Commit `Cargo.lock` by default; for public libraries, also test latest67 dependency resolution because consumers use `Cargo.toml`.68- Avoid exact `rust-toolchain.toml` version pins unless reproducibility,69 nightly, embedded/custom targets, or release policy requires them.7071## Verification Ladder7273Start narrow, then broaden:7475```bash76cargo check -p <crate>77cargo test -p <crate> <test_name>78cargo fmt --all -- --check79cargo clippy --workspace --all-targets --all-features --locked -- -D warnings80cargo test --workspace --all-targets --all-features --locked81cargo test --doc --workspace --locked82```8384Use `cargo nextest run` when configured. Add `cargo hack`, `cargo deny`,85`cargo audit`, `cargo semver-checks`, or release tooling only when the repo or86change surface warrants it.8788## Helper Scripts8990- `scripts/discover-rust-gates.mjs [repo-root]`: print likely Rust gates.91- `scripts/check-reference-links.mjs <skill-dir...>`: validate local skill links.92- `scripts/check-trigger-evals.mjs <skill-dir...>`: validate trigger eval JSON.
BjornMelin