axiom-ios-concurrency

axiom-ios-concurrency is a skill for Claude Code, Codex from ComeOnOliver/skillshub. It costs 48 tokens per session (1,945 once invoked), scanned A, original, MIT.

A guide for writing and fixing concurrent Swift code, where multiple tasks can run at once. It covers Swift 6 rules such as async/await, actors, @MainActor, and Sendable.

In plain words
What is it for?
It is for diagnosing Swift concurrency errors, moving work off the main thread, handling shared data safely, and improving async code performance.
Why use it?
It helps prevent data races, actor-isolation errors, and app freezes caused by doing slow work on the user-interface thread.

Skill for Claude CodeCodex

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

Good fit It is for diagnosing Swift concurrency errors, moving work off the main thread, handling shared data safely, and improving async code performance.

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Install with agentmods
npx agentmods add skills/comeonoliver/skillshub/axiom-ios-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-ios-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.

agentmods badge for axiom-ios-concurrency

README.md
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Your own site
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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.

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Your own site · 80×15
<a href="https://agentmods.dev/skills/comeonoliver/skillshub/axiom-ios-concurrency"><img src="https://agentmods.dev/badge/skills/comeonoliver/skillshub/axiom-ios-concurrency.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,945 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00048 $0.01945
Opus 5 $0.00024 $0.00972
Sonnet 5 $0.00010 $0.00389
Haiku 4.5 $0.00005 $0.00194

Measured 9d ago against content hash 719f09843cbe, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

axiom-ios-concurrency scanned grade A with 0 findings 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 9d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/CharlesWiltgen/Axiom/axiom-ios-concurrency/SKILL.md · 211 lines

How it starts

The opening of the file, as written. The whole thing — 211 lines — stays where its author put it; the contents beside it link to each section on GitHub.

iOS Concurrency Router

You MUST use this skill for ANY concurrency, async/await, threading, or Swift 6 concurrency work.

When to Use

Use this router when:

  • Writing async/await code
  • Seeing concurrency errors (data races, actor isolation)
  • Working with @MainActor
  • Dealing with Sendable conformance
  • Optimizing Swift performance
  • Migrating to Swift 6 concurrency
  • App freezes during loading (likely main thread blocking)

Conflict Resolution

ios-concurrency vs ios-performance: When app freezes or feels slow:

  1. Try ios-concurrency FIRST — Main thread blocking is the #1 cause of UI freezes. Check for synchronous work on @MainActor before profiling.
  2. Only use ios-performance if concurrency fixes don't help — Profile after ruling out obvious blocking.

ios-concurrency vs ios-build: When seeing Swift 6 concurrency errors:

  • Use ios-concurrency, NOT ios-build — Concurrency errors are CODE issues, not environment issues
  • ios-build is for "No such module", simulator issues, build failures unrelated to Swift language errors

ios-concurrency vs ios-data: When concurrency errors involve Core Data or SwiftData:

  • Core Data threading (NSManagedObjectContext thread confinement, performBackgroundTask) → use ios-data first — Core Data has its own threading model distinct from Swift concurrency
  • SwiftData + @MainActor ModelContext → use ios-concurrency — This is Swift concurrency isolation
  • General "background saves losing data" → use ios-data first — Framework-specific threading rules take priority

Rationale: A 2-second freeze during data loading is almost always await on main thread or missing background dispatch. Domain knowledge solves this faster than Time Profiler. Core Data threading violations need Core Data-specific fixes, not generic concurrency patterns.

Routing Logic

Swift Concurrency Issues

Swift 6 concurrency patterns/skill axiom-swift-concurrency

  • async/await patterns
  • @MainActor usage
  • Actor isolation
  • Sendable conformance
  • Data race prevention
  • Swift 6 migration

Read the full file on GitHub · 211 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. 9d ago First seen · 211 lines · 48 tokens per session scan A 719f09843cbe

Subscribe to this mod's changes

axiom-ios-concurrency is a skill published in the GitHub repository ComeOnOliver/skillshub (63 stars, last pushed 2mo ago), licensed MIT. It adds 48 tokens to every session and 1,945 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.