swift-expert

swift-expert is a skill for Claude Code, Codex from eric861129/SKILLS_All-in-one. It costs 98 tokens per session (1,301 once invoked), scanned A, original, MIT.

A Swift development assistant for Apple apps using Swift, SwiftUI, protocols, and async/await. It covers iPhone, Mac, Apple Watch, and Apple TV applications, including state management and thread safety.

In plain words
What is it for?
Use it to build SwiftUI views, manage app state, design protocols, implement asynchronous work, handle thread-safe code, debug Swift issues, and write XCTest tests.
Why use it?
It helps structure Swift code and catch build, concurrency, and warning problems before they reach users. It also provides patterns for testing asynchronous code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to build SwiftUI views, manage app state, design protocols, implement asynchronous work, handle thread-safe code, debug Swift issues, and write XCTest tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/eric861129/skills_all-in-one/swift-expert
Install

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.

Any agent
npx skills add eric861129/SKILLS_All-in-one --skill swift-expert
Clone the repo
git clone --depth 1 https://github.com/eric861129/SKILLS_All-in-one

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for swift-expert

README.md
[![agentmods](https://agentmods.dev/badge/skills/eric861129/skills_all-in-one/swift-expert/github.svg)](https://agentmods.dev/skills/eric861129/skills_all-in-one/swift-expert)
Your own site
<a href="https://agentmods.dev/skills/eric861129/skills_all-in-one/swift-expert"><img src="https://agentmods.dev/badge/skills/eric861129/skills_all-in-one/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.

agentmods 80×15 button for swift-expert

Your own site · 80×15
<a href="https://agentmods.dev/skills/eric861129/skills_all-in-one/swift-expert"><img src="https://agentmods.dev/badge/skills/eric861129/skills_all-in-one/swift-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 98 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,301 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00098 $0.01301
Opus 5 $0.00049 $0.00651
Sonnet 5 $0.00020 $0.00260
Haiku 4.5 $0.00010 $0.00130

Measured 7d ago against content hash d3c27b68cb68, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

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 7d 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
public/SKILLS/Development & Code Tools/swift-expert/SKILL.md · 164 lines

How it starts

The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Swift Expert

Core Workflow

  1. Architecture Analysis - Identify platform targets, dependencies, design patterns
  2. Design Protocols - Create protocol-first APIs with associated types
  3. Implement - Write type-safe code with async/await and value semantics
  4. Optimize - Profile with Instruments, ensure thread safety
  5. Test - Write comprehensive tests with XCTest and async patterns

Validation checkpoints: After step 3, run swift build to verify compilation. After step 4, run swift build -warnings-as-errors to surface actor isolation and Sendable warnings. After step 5, run swift test and 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)
        }
    }
}

Read the full file on GitHub · 164 lines

Files

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.

Changes

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.

  1. 7d ago First seen · 164 lines · 98 tokens per session scan A d3c27b68cb68

Subscribe to this mod's changes

swift-expert is a skill published in the GitHub repository eric861129/SKILLS_All-in-one (52 stars, last pushed 4mo ago), licensed MIT. It adds 98 tokens to every session and 1,301 once invoked, about $0.0005 per session on Opus 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 2026-09-03.

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