Rust Code Studio

Design or review public API, decide breaking vs additive change, audit accidental pub, plan crate boundary split, gate any change touching the public surface. Tier-2 lead for API surface, crate boundaries, and semver discipline. Owns the re-export strategy, #[non_exhaustive] / sealed-trait policy, and API-GATE sign-off.

Trait and type design specialist: trait design, type-state machines, builders, sealed traits, newtypes, GATs, trait-objects-vs-generics, standard impls (From/TryFrom/Display/Error/Iterator/Default). Use to design a public API surface or make illegal states unrepresentable. Trigger phrases: "design this trait", "typestate builder", "sealed trait", "newtype pattern", "object safety", "illegal states unrepresentable", "GAT", "From vs TryFrom".

Tokio runtime and async-correctness specialist. Owns cancellation safety, select!, streams, spawning, JoinHandles, Send/'static bounds, async traits, and timeouts. Use when reviewing or writing async code, debugging a hang/race/cancellation bug, auditing spawn sites, reasoning about structured concurrency, or deciding between spawn vs. spawn_blocking.

Tier-2 lead for async architecture and service design. Owns tokio runtime topology, web stack choice (axum/actix/hyper/tower), service-level concurrency model, backpressure, and the ASYNC-GATE. Use when designing or reviewing an async service, choosing a web framework, wiring up shutdown, handling backpressure, or auditing cancellation safety.

Implements build infrastructure: build.rs, CI configs, cross-compilation, xtask, cargo-hack feature matrices, OUT_DIR codegen. Use to set up/fix build scripts, add cross targets, debug CI, or verify all feature combinations compile. (tooling-lead owns build policy + BUILD-GATE; this agent implements.) Trigger phrases: "build.rs", "cross-compile", "cargo hack", "xtask", "OUT_DIR", "rerun-if", "CI matrix".

Add a Rust dependency / add-dep / vet a crate — run the full vetting pipeline (RUSTSEC, license, MSRV, features) before touching Cargo.toml.

Adopt / onboard an existing Rust crate or workspace into studio governance — reverse-engineer structure, infer domains and standards, summarize the public API, catalog debt/gaps, then delegate the docs.

ADR / architecture decision record — write, number, and file a decision record using the studio template: context, options, decision, consequences, alternatives.

Detect semver hazards, accidental-pub leaks, and required version bump in a public API change — runs cargo public-api / cargo semver-checks, classifies every change with api-design-lead, and drafts mitigations.

Design or revise module/crate architecture — boundaries, dependency direction, key types, and an architecture doc. Drives map → decide → record → hand off via chief-architect.

10 hooks across 7 events

rust-analyzer

One finding per line, severity-tagged, evidence over prose — the studio reviewer voice

Stream this PR's CI check status while /resolve-pr is shepherding it, so failing checks surface as notifications without polling. No-op when gh is unavailable.