Axum Scaffolder

"An API that is not documented is an API that is not finished. Security by default: every route is protected unless explicitly marked public."

Core Philosophy

Axum is Rust's most ergonomic HTTP framework, built on Tower's middleware ecosystem and Tokio's async runtime. This skill scaffolds production-ready Axum APIs with OpenAPI documentation, security middleware, and proper error handling from day one. The OpenAPI spec is generated from code, not written separately; routes are versioned from the first commit; auth is applied at the router level so anonymous access is explicit; request and response data flow through typed extractors and impl IntoResponse, never raw Request parsing.

Non-Negotiable Constraints:

1. OPENAPI-FIRST — #[utoipa::path] on every handler; utoipa::OpenApi derive on the app; the spec must be accurate.
2. VERSIONING FROM DAY ONE — /api/v1/ prefix on all routers; no unversioned routes.
3. SECURITY BY DEFAULT — Tower middleware for JWT validation; anonymous access is explicit (/health, /docs).
4. TYPED EXTRACTORS — all request data via axum::extract::{Json, Path, Query, State}; no raw Request parsing.
5. TYPED RESPONSES — impl IntoResponse with explicit status codes; errors as RFC 7807 Problem Details via AppError.

Full principle table, KB lookups, discipline rules, anti-patterns, and error recovery live in references/conventions.md.

Workflow

DETECT      Existing Cargo.toml/deps, AppState/AppError/main router, Rust edition + Tokio version,
            existing utoipa setup.

CONFIGURE   Add deps to Cargo.toml; create src/errors.rs (AppError), src/state.rs (AppState),
            src/openapi.rs (OpenApi derive).  (Templates in router-template.md.)

SCAFFOLD    Feature router with typed handlers; request/response models with ToSchema;
            #[utoipa::path] on handlers; feature error type with From<FeatureError> for AppError.

SECURE      Add JWT validation middleware; apply to protected route groups; leave /health + /docs
            unprotected.  (Layer ordering + JWT in middleware-patterns.md.)

DOCUMENT    #[utoipa::path] on all handlers; ToSchema on all types; OpenApi derive with all
            paths/schemas; /docs route serving the OpenAPI UI.

VERIFY      cargo build · cargo test · cargo clippy -- -D warnings · curl /health → 200 ·
            curl /docs → OpenAPI UI · protected routes → 401 without token.

Exit criteria: all routes scaffolded, documented, secured, and verified.

State Block

<axum-scaffold-state>
phase: DETECT | CONFIGURE | SCAFFOLD | SECURE | DOCUMENT | VERIFY | COMPLETE
feature_name: [name]
edition: [2015 | 2018 | 2021 | 2024]
tokio_version: [1.x | unknown]
utoipa_configured: true | false
auth_middleware: true | false
rate_limiting: true | false
cors_configured: true | false
health_check: true | false
openapi_ui: true | false
build_status: pass | fail | not-run
last_action: [description]
next_action: [description]
</axum-scaffold-state>

Output Template

• Cargo.toml deps, errors/AppError, auth/JWT, openapi, main, health, scaffold checklist — references/router-template.md.
• Layer ordering, JWT, CORS, rate limiting, tracing, timeout, compression, security headers — references/middleware-patterns.md.
• Principle table, KB lookups, discipline rules, anti-patterns, error recovery — references/conventions.md.

Integration with Other Skills