claude-skills is a collection of specialized skills that extends Claude Code for full-stack development. Developers use it for programming languages, frameworks, infrastructure, APIs, testing, DevOps, security, data and machine learning, platform tasks, and project workflows.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add Jeffallan/claude-skills --skill swift-expertgit clone --depth 1 https://github.com/Jeffallan/claude-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/jeffallan/claude-skills/swift-expert)<a href="https://agentmods.dev/skills/jeffallan/claude-skills/swift-expert"><img src="https://agentmods.dev/badge/skills/jeffallan/claude-skills/swift-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/jeffallan/claude-skills/swift-expert"><img src="https://agentmods.dev/badge/skills/jeffallan/claude-skills/swift-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00098 | $0.01374 |
| Opus 5.5 | $0.00039 | $0.00550 |
| Sonnet 5.5 | $0.00020 | $0.00275 |
| Haiku 4.5 | $0.00010 | $0.00137 |
Grade A, and why
swift-expert scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 13d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
func fetch(id: Entity.ID) async throws -> Entity Copies of this mod
1 near-identical copy found in the catalogue:
- swift-expert — 88% identical, 5 lines differ
How it starts
The opening of the file, as written. The whole thing — 169 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Swift Expert
Core Workflow
- Architecture Analysis - Identify platform targets, dependencies, design patterns
- Design Protocols - Create protocol-first APIs with associated types
- Implement - Write type-safe code with async/await and value semantics
- Optimize - Profile with Instruments, ensure thread safety
- Test - Write comprehensive tests with XCTest and async patterns
Validation checkpoints: After step 3, run
swift buildto verify compilation. After step 4, runswift build -warnings-as-errorsto surface actor isolation and Sendable warnings. After step 5, runswift testand confirm all async tests pass.
Reference Guide
Load detailed guidance based on context:
| Topic | Reference | Load When |
|---|---|---|
| SwiftUI | references/swiftui-patterns.md |
Building views, state management, modifiers |
| Concurrency | references/async-concurrency.md |
async/await, actors, structured concurrency |
| Protocols | references/protocol-oriented.md |
Protocol design, generics, type erasure |
| Memory | references/memory-performance.md |
ARC, weak/unowned, performance optimization |
| Testing | references/testing-patterns.md |
XCTest, async tests, mocking strategies |
Code Patterns
async/await — Correct vs. Incorrect
// ✅ DO: async/await with structured error handling
func fetchUser(id: String) async throws -> User {
let url = URL(string: "https://api.example.com/users/\(id)")!
let (data, _) = try await URLSession.shared.data(from: url)
return try JSONDecoder().decode(User.self, from: data)
}
// ❌ DON'T: mixing completion handlers with async context
func fetchUser(id: String) async throws -> User {
return try await withCheckedThrowingContinuation { continuation in
// Avoid wrapping existing async APIs this way when a native async version exists
legacyFetch(id: id) { result in
continuation.resume(with: result)
}
}
}
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 13d ago First seen · 169 lines · 98 tokens per session scan A a50b57faf2ed
swift-expert is a skill published in the GitHub repository Jeffallan/claude-skills (11,907 stars, last pushed today), licensed MIT. It adds 98 tokens to every session and 1,374 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-04.
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