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 rshankras/claude-code-apple-skills --skill concurrencygit clone --depth 1 https://github.com/rshankras/claude-code-apple-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/rshankras/claude-code-apple-skills/concurrency)<a href="https://agentmods.dev/skills/rshankras/claude-code-apple-skills/concurrency"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/concurrency/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/rshankras/claude-code-apple-skills/concurrency"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/concurrency.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00052 | $0.03220 |
| Opus 5.5 | $0.00021 | $0.01288 |
| Sonnet 5.5 | $0.00010 | $0.00644 |
| Haiku 4.5 | $0.00005 | $0.00322 |
Grade A, and why
swift-concurrency-updates 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 yesterday.
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.
How it starts
The opening of the file, as written. The whole thing — 386 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Swift 6.2 Concurrency Updates
Swift 6.2 introduces "Approachable Concurrency" -- a set of changes that make strict concurrency dramatically easier to adopt. Code runs on @MainActor by default, async functions stay on the calling actor, and you explicitly request background execution with @concurrent.
This skill covers only the Swift 6.2 specific changes. For general concurrency patterns (actors, TaskGroup, AsyncSequence, Sendable, cancellation), see the swift/concurrency-patterns skill.
When This Skill Activates
- User is adopting Swift 6.2 concurrency features
- User asks about default MainActor inference or the "infer main actor" build setting
- User encounters data-race errors that Swift 6.2 resolves
- User asks about
@concurrent, isolated conformances, or approachable concurrency - User wants to migrate from Swift 6.0/6.1 strict concurrency to 6.2
- User asks how async functions behave differently in Swift 6.2
- User needs to offload CPU-intensive work to a background thread in Swift 6.2
What Changed in Swift 6.2 vs Before
Swift 6.2 Changes at a Glance
| Feature | Before (6.0/6.1) | After (6.2) |
|---|---|---|
| Default isolation | Nothing inferred; manual @MainActor everywhere |
Opt-in mode infers @MainActor on everything |
| Async function execution | Hops to generic concurrent executor | Stays on calling actor |
@MainActor type conforming to protocol |
Compiler error for non-isolated protocols | Isolated conformances: @MainActor Protocol |
| Background execution | Task.detached or manual nonisolated functions |
@concurrent attribute |
| Global/static mutable state | Required @MainActor annotation or Sendable |
Default MainActor mode handles it automatically |
1. Async Functions Stay on the Calling Actor
In Swift 6.2, async functions without specific actor isolation stay on whatever actor called them, instead of hopping to the generic concurrent executor as in 6.0/6.1 -- eliminating a common source of data-race errors with no code changes required.
What ships with it
1 file 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.
- yesterday First seen · 386 lines · 52 tokens per session scan A cb543398bb19
swift-concurrency-updates is a skill published in the GitHub repository rshankras/claude-code-apple-skills (864 stars, last pushed 2d ago), licensed MIT. It adds 52 tokens to every session and 3,220 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-11-05.
swift-concurrency-updates compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| swift-concurrency-updatesrshankras/claude-code-apple-skills | Skill | 864 | 2d ago | MIT | A | 52 | Claude Code |
| swift-expertpersonamanagmentlayer/pcl | Skill | 44 | 11d ago | Apache-2.0 | A | 76 | Claude Code |
| ios-expertpersonamanagmentlayer/pcl | Skill | 44 | 11d ago | Apache-2.0 | A | 64 | Claude Code |
| swift6-concurrencymarkdavidgan/apple-dev-skills | Skill | 5 | 2mo ago | MIT | A | 74 | Claude Code |
| ios-swiftui-productJasonColapietro/ios-app-dev-skills | Skill | 9 | 2mo ago | MIT | A | 67 | Codex |
| swiftui-maxDev869/swift-tothemax | Skill | 7 | 4mo ago | MIT | A | 271 | Claude Code |
| swift-languageDev869/swift-tothemax | Skill | 7 | 4mo ago | MIT | A | 167 | Claude Code |