rust
Rust language patterns and ecosystem covering ownership, borrowing, lifetimes, error handling (Result/Option, thiserror, anyhow), async with Tokio, traits, generics, serde serialization, Cargo workspaces, and testing. Includes axum web framework, ratatui terminal UI, clap CLI parsing, criterion benchmarking, cargo-deny supply chain security, cargo-dist binary distribution, and release-plz changelog automation. Use when writing Rust code, designing ownership models, building async services with Tokio/axum, creating terminal UIs with ratatui, setting up CLI applications with clap, configuring CI/CD pipelines for Rust, benchmarking with criterion, auditing dependencies with cargo-deny, or distributing binaries with cargo-dist.
What this skill does
# Rust
## Overview
Rust is a systems programming language focused on safety, concurrency, and performance. The ownership system guarantees memory safety without garbage collection, and the type system enforces thread safety at compile time.
**When to use:** Systems programming, web services (axum), CLI tools (clap), terminal UIs (ratatui), WebAssembly, performance-critical applications, anything requiring memory safety without runtime overhead.
**When NOT to use:** Rapid prototyping where compile times matter more than safety, simple scripting tasks, projects where the team has no Rust experience and deadlines are tight.
## Quick Reference
| Pattern | API / Tool | Key Points |
| ------------------- | ----------------------------------- | ------------------------------------ |
| Ownership transfer | `let b = a;` | `a` is moved, no longer usable |
| Borrowing | `&T` / `&mut T` | One mutable OR many immutable refs |
| Lifetime annotation | `fn f<'a>(x: &'a str) -> &'a str` | Ties output lifetime to input |
| Error propagation | `?` operator | Converts and propagates errors |
| Custom errors | `thiserror::Error` derive | Structured error types with Display |
| Ad-hoc errors | `anyhow::Result<T>` | Context chaining for applications |
| Async runtime | `#[tokio::main]` | Entry point for async programs |
| Spawn task | `tokio::spawn(async { })` | Concurrent async task execution |
| HTTP router | `axum::Router::new().route(...)` | Composable routing with extractors |
| Extractors | `Json<T>`, `Path<T>`, `State<T>` | Type-safe request parsing |
| Serialization | `#[derive(Serialize, Deserialize)]` | serde with format-agnostic derives |
| CLI parsing | `#[derive(Parser)]` | clap derive API for arg parsing |
| TUI rendering | `terminal.draw(\|f\| { })` | Immediate-mode ratatui rendering |
| Benchmarking | `criterion::Criterion` | Statistical benchmarking framework |
| Dep auditing | `cargo deny check` | License, vulnerability, source audit |
| Binary release | `cargo dist init` | Cross-platform binary distribution |
| Changelog | `release-plz update` | Auto semver bump and changelog |
## Common Mistakes
| Mistake | Correct Pattern |
| --------------------------------------- | --------------------------------------------- |
| Returning reference to local variable | Return owned type or use lifetime parameter |
| Using `unwrap()` in library code | Return `Result` and let caller decide |
| `clone()` to satisfy borrow checker | Restructure code to avoid the borrow conflict |
| Blocking in async context | Use `tokio::task::spawn_blocking` |
| Shared mutable state without sync | Use `Arc<Mutex<T>>` or channels |
| `String` where `&str` suffices | Accept `&str` in function parameters |
| Ignoring `must_use` warnings | Handle or explicitly discard with `let _ =` |
| Large enum variants | Box the large variant to reduce overall size |
| `async fn` in traits without bounds | Add `Send` bound or use `async-trait` crate |
| Missing `#[tokio::test]` on async tests | Use `#[tokio::test]` instead of `#[test]` |
## Delegation
- **Code exploration**: Use `Explore` agent
- **Architecture review**: Use `Task` agent
- **Code review**: Delegate to `code-reviewer` agent
> If the `docker` skill is available, delegate multi-stage container build patterns to it.
> If the `github-actions` skill is available, delegate CI pipeline configuration to it.
> If the `openapi` skill is available, delegate API specification and code generation to it.
## References
- [Ownership, borrowing, lifetimes, and type system patterns](references/ownership-and-types.md)
- [Error handling with Result, Option, thiserror, and anyhow](references/error-handling.md)
- [Async programming with Tokio runtime and concurrency](references/async-tokio.md)
- [Web APIs and backends with axum, tower, and sqlx](references/axum-web.md)
- [Terminal user interfaces with ratatui and crossterm](references/ratatui-tui.md)
- [CLI applications with clap, config, and signal handling](references/cli-applications.md)
- [Testing patterns and criterion benchmarking](references/testing-and-benchmarks.md)
- [Release pipeline with cargo-deny, cargo-dist, and release-plz](references/release-pipeline.md)
Related in Design
contribute
IncludedLocal-only OSS contribution command center. Auto-refreshes the user's in-flight PR and issue state on invoke so conversations start with full context — no need to brief Claude on what's in flight. Helps the user find issues to contribute to on GitHub, builds per-repo dossiers of what each upstream expects (CLA, DCO, branch convention, AI policy, draft-first, review bots, issue templates), runs deterministic gates before any external action so AI-assisted contributions don't reach maintainers as slop. State is markdown-only: candidate files at ~/.contribute-system/candidates/, repo dossiers at ~/.contribute-system/research/, append-only event log at ~/.contribute-system/log.jsonl. No database, no cloud calls. Use when the user asks about their PRs / issues / contributions, wants to find new work to take on, claim an issue, build/refresh a repo's dossier, or draft a Design Issue or PR. Trigger with "/contribute", "what's my PR status", "find a contribution", "claim issue X", "draft a Design Issue for Y", "refresh dossier for Z".
architectural-analysis
IncludedUser-triggered deep architectural analysis of a codebase or scoped subtree across eight modes — information architecture, data flow, integration points, UI surfaces, interaction patterns, data model, control flow, and failure modes. This skill should be used when the user asks to "diagram this codebase," "map the architecture," "show the data flow," "give me an ERD," "trace control flow," "find the integration points," "verify the layout pattern," "audit the UX architecture," or any similar request whose primary deliverable is mermaid diagrams plus cited reports under docs/architecture/. Dispatches haiku/sonnet sub-agents in parallel for per-mode exploration, then verifies every citation mechanically before any node lands in a diagram. Not for one-off prose explanations of code (use code-explanation) or for high-level system design from scratch (use system-design).
mcp
IncludedModel Context Protocol (MCP) server development and tool management. Languages: Python, TypeScript. Capabilities: build MCP servers, integrate external APIs, discover/execute MCP tools, manage multi-server configs, design agent-centric tools. Actions: create, build, integrate, discover, execute, configure MCP servers/tools. Keywords: MCP, Model Context Protocol, MCP server, MCP tool, stdio transport, SSE transport, tool discovery, resource provider, prompt template, external API integration, Gemini CLI MCP, Claude MCP, agent tools, tool execution, server config. Use when: building MCP servers, integrating external APIs as MCP tools, discovering available MCP tools, executing MCP capabilities, configuring multi-server setups, designing tools for AI agents.
react-native-skia
IncludedDesign, build, debug, and optimise high-polish animated graphics in React Native or Expo using @shopify/react-native-skia, Reanimated, and Gesture Handler. Use when the user wants canvas-driven UI, shaders, paths, rich text, image filters, sprite fields, Skottie, video frames, snapshots, web CanvasKit setup, or performance tuning for custom motion-heavy elements such as loaders, hero art, cards, charts, progress indicators, particle systems, or gesture-driven surfaces. Also use when the user asks for fluid, glow, glass, blob, parallax, 60fps/120fps, or GPU-friendly animated effects in React Native, even if they do not explicitly say "Skia". Do not use for ordinary form/layout work with standard views.
plaid
IncludedProduct Led AI Development — guides founders from idea to launched product. Six capabilities: Idea (discover a product idea), Validate (pressure-test the idea against fatal flaws, problem reality, competition, and 2-week MVP feasibility), Plan (vision intake + document generation), Design (translate image references into a design.md spec), Launch (go-to-market strategy), and Build (roadmap execution). Use when someone says "PLAID", "plaid idea", "help me find an idea", "product idea", "idea from my business", "idea from my expertise", "plaid validate", "validate my idea", "pressure-test", "is this idea good", "find fatal flaws", "validate the problem", "plan a product", "define my vision", "generate a PRD", "product strategy", "plaid design", "design from image", "translate image to design", "create design.md", "extract design tokens", "plaid launch", "go-to-market", "launch plan", "GTM strategy", "launch playbook", "plaid build", "build the app", "start building", or "execute the roadmap".
nextjs-framer-motion-animations
IncludedAdds production-safe Motion for React or Framer Motion animations to Next.js apps, including reveal, hover and tap micro-interactions, whileInView, stagger, AnimatePresence, layout and layoutId transitions, reorder, scroll-linked UI, and lightweight route-content transitions. Use when the user asks to add, refactor, or debug Motion or Framer Motion in App Router or Pages Router codebases, especially around server/client boundaries, reduced motion, LazyMotion, bundle size, hydration, or route transitions. Avoid for GSAP-style timelines, WebGL or 3D scenes, heavy scroll storytelling, or CSS-only effects unless Motion is explicitly requested.