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 koshkinvv/ios-agent-skills --skill ios-concurrencygit clone --depth 1 https://github.com/koshkinvv/ios-agent-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/koshkinvv/ios-agent-skills/ios-concurrency)<a href="https://agentmods.dev/skills/koshkinvv/ios-agent-skills/ios-concurrency"><img src="https://agentmods.dev/badge/skills/koshkinvv/ios-agent-skills/ios-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/koshkinvv/ios-agent-skills/ios-concurrency"><img src="https://agentmods.dev/badge/skills/koshkinvv/ios-agent-skills/ios-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 | $0.00191 | $0.02469 |
| Opus 5 | $0.00096 | $0.01234 |
| Sonnet 5 | $0.00038 | $0.00494 |
| Haiku 4.5 | $0.00019 | $0.00247 |
Grade A, and why
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 11d 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.
How it starts
The opening of the file, as written. The whole thing — 331 lines — stays where its author put it; the contents beside it link to each section on GitHub.
iOS Concurrency Skill
Core Rules
- Use async/await for ALL new asynchronous code. Do not use completion handlers or Combine for async operations in new code.
- Use structured concurrency (Task, TaskGroup). Avoid unstructured task leaks. Prefer
async letorTaskGroupover spawning looseTask {}blocks. - Mark UI-updating code with @MainActor. SwiftUI views are already
@MainActor-isolated. UIKit code that touches UI must run on@MainActor. - Use actors for shared mutable state instead of locks, semaphores, or serial dispatch queues.
- All types crossing actor boundaries must be Sendable. The compiler enforces this in strict concurrency mode.
- Prefer value types (struct, enum) for Sendable. They are implicitly Sendable when all stored properties are Sendable.
- Use
withCheckedContinuationto bridge callback-based APIs to async/await. Never resume a continuation more than once. - Use
AsyncStreamfor bridging delegate/callback patterns toAsyncSequence. Task.detachedis rarely needed. UseTask {}with explicit actor isolation instead. Detached tasks lose actor context and priority inheritance.- Always handle Task cancellation cooperatively. Check
Task.isCancelledor calltry Task.checkCancellation()at appropriate points.
Decision Guide
| Scenario | Solution |
|---|---|
| Single async operation | async func / Task {} |
| Multiple independent operations | TaskGroup / async let |
| Sequential dependent operations | await one after another |
| Shared mutable state | actor |
| UI updates from background | @MainActor / MainActor.run {} |
| Bridge callback API | withCheckedContinuation / withCheckedThrowingContinuation |
| Bridge delegate pattern | AsyncStream with continuation |
| Streaming data | AsyncSequence / AsyncStream |
| Debounce user input | Task cancellation pattern |
| Non-Sendable legacy type | @preconcurrency import / @unchecked Sendable (last resort) |
| Combine publisher to async | .values property on publisher |
| Timer / periodic work | AsyncTimerSequence (from swift-async-algorithms) or AsyncStream |
| Parallel with limit | TaskGroup with semaphore-like counter |
What ships with it
3 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.
- 11d ago First seen · 331 lines · 191 tokens per session scan A 14441ffd7861
ios-concurrency is a skill published in the GitHub repository koshkinvv/ios-agent-skills (6 stars, last pushed 5mo ago), licensed MIT. It adds 191 tokens to every session and 2,469 once invoked, about $0.0010 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 2026-08-31.
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