axiom-swift-concurrency

axiom-swift-concurrency is a skill for Claude Code, Codex from ComeOnOliver/skillshub. It costs 89 tokens per session (6,270 once invoked), scanned A, original, MIT.

A guide to Swift concurrency, the language features for running work safely at the same time. It explains async/await, actors, the main thread, and data-race safety in Swift 6.

In plain words
What is it for?
Use it when fixing actor-isolation or Sendable errors, converting callbacks to async/await, moving heavy work off the user-interface thread, or designing concurrent iOS code.
Why use it?
It helps resolve concurrency errors and prevent crashes or inconsistent data when code runs across threads.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it when fixing actor-isolation or Sendable errors, converting callbacks to async/await, moving heavy work off the user-interface thread, or designing concurrent iOS code.

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Install with agentmods
npx agentmods add skills/comeonoliver/skillshub/axiom-swift-concurrency
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 ComeOnOliver/skillshub --skill axiom-swift-concurrency
Clone the repo
git clone --depth 1 https://github.com/ComeOnOliver/skillshub

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.

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README.md
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Per session 89 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,270 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 $0.00089 $0.06270
Opus 5 $0.00044 $0.03135
Sonnet 5 $0.00018 $0.01254
Haiku 4.5 $0.00009 $0.00627

Measured 8d ago against content hash eb8bb4946bfc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

axiom-swift-concurrency 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 8d 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.

return try context.fetch(descriptor)
skills/CharlesWiltgen/Axiom/axiom-swift-concurrency/SKILL.md · 955 lines

How it starts

The opening of the file, as written. The whole thing — 955 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Swift 6 Concurrency Guide

Purpose: Progressive journey from single-threaded to concurrent Swift code Swift Version: Swift 6.0+, Swift 6.2+ for @concurrent iOS Version: iOS 17+ (iOS 18.2+ for @concurrent) Xcode: Xcode 16+ (Xcode 16.2+ for @concurrent) Context: WWDC 2025-268 "Embracing Swift concurrency" - approachable path to data-race safety

When to Use This Skill

Use this skill when:

  • Starting a new project and deciding concurrency strategy
  • Debugging Swift 6 concurrency errors (actor isolation, data races, Sendable warnings)
  • Deciding when to introduce async/await vs concurrency
  • Implementing @MainActor classes or async functions
  • Converting delegate callbacks to async-safe patterns
  • Deciding between @MainActor, nonisolated, @concurrent, or actor isolation
  • Resolving "Sending 'self' risks causing data races" errors
  • Making types conform to Sendable
  • Offloading CPU-intensive work to background threads
  • UI feels unresponsive and profiling shows main thread bottleneck

Do NOT use this skill for:

  • General Swift syntax (use Swift documentation)
  • SwiftUI-specific patterns (use axiom-swiftui-debugging or axiom-swiftui-performance)
  • API-specific patterns (use API documentation)

Core Philosophy: Start Single-Threaded

Apple's Guidance (WWDC 2025-268): "Your apps should start by running all of their code on the main thread, and you can get really far with single-threaded code."

The Progressive Journey

Single-Threaded → Asynchronous → Concurrent → Actors
     ↓                ↓             ↓           ↓
   Start here    Hide latency   Background   Move data
                 (network)      CPU work     off main

When to advance:

  1. Stay single-threaded if UI is responsive and operations are fast
  2. Add async/await when high-latency operations (network, file I/O) block UI
  3. Add concurrency when CPU-intensive work (image processing, parsing) freezes UI
  4. Add actors when too much main actor code causes contention

Read the full file on GitHub · 955 lines

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. 8d ago First seen · 955 lines · 89 tokens per session scan A eb8bb4946bfc

Subscribe to this mod's changes

axiom-swift-concurrency is a skill published in the GitHub repository ComeOnOliver/skillshub (63 stars, last pushed 2mo ago), licensed MIT. It adds 89 tokens to every session and 6,270 once invoked, about $0.0004 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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