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 SethCalkins/claude-ios-swift-plugin --skill swift-concurrency-expertgit clone --depth 1 https://github.com/SethCalkins/claude-ios-swift-pluginWrote 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/sethcalkins/claude-ios-swift-plugin/swift-concurrency-expert)<a href="https://agentmods.dev/skills/sethcalkins/claude-ios-swift-plugin/swift-concurrency-expert"><img src="https://agentmods.dev/badge/skills/sethcalkins/claude-ios-swift-plugin/swift-concurrency-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.
<a href="https://agentmods.dev/skills/sethcalkins/claude-ios-swift-plugin/swift-concurrency-expert"><img src="https://agentmods.dev/badge/skills/sethcalkins/claude-ios-swift-plugin/swift-concurrency-expert.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 | $0.00045 | $0.00481 |
| Opus 5 | $0.00023 | $0.00241 |
| Sonnet 5 | $0.00009 | $0.00096 |
| Haiku 4.5 | $0.00005 | $0.00048 |
Grade A, and why
swift-concurrency-expert 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.
This is a copy
95% identical to swift-concurrency-expert — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
Swift Concurrency Expert
Overview
Review and fix Swift Concurrency issues in Swift 6.2+ codebases by applying actor isolation, Sendable safety, and modern concurrency patterns with minimal behavior changes.
Workflow
1. Triage the issue
- Capture the exact compiler diagnostics and the offending symbol(s).
- Check project concurrency settings: Swift language version (6.2+), strict concurrency level, and whether approachable concurrency (default actor isolation / main-actor-by-default) is enabled.
- Identify the current actor context (
@MainActor,actor,nonisolated) and whether a default actor isolation mode is enabled. - Confirm whether the code is UI-bound or intended to run off the main actor.
2. Apply the smallest safe fix
Prefer edits that preserve existing behavior while satisfying data-race safety.
Common fixes:
- UI-bound types: annotate the type or relevant members with
@MainActor. - Protocol conformance on main actor types: make the conformance isolated (e.g.,
extension Foo: @MainActor SomeProtocol). - Global/static state: protect with
@MainActoror move into an actor. - Background work: move expensive work into a
@concurrentasync function on anonisolatedtype or use anactorto guard mutable state. - Sendable errors: prefer immutable/value types; add
Sendableconformance only when correct; avoid@unchecked Sendableunless you can prove thread safety.
Reference material
- See
references/swift-6-2-concurrency.mdfor Swift 6.2 changes, patterns, and examples. - See
references/swift-6-2-hang-elimination.mdfor eliminating hangs using Task.immediate, priority escalation, named tasks, and default main actor isolation. - See
references/approachable-concurrency.mdwhen the project is opted into approachable concurrency mode. - See
references/swiftui-concurrency-tour-wwdc.mdfor SwiftUI-specific concurrency guidance.
What ships with it
4 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 · 39 lines · 45 tokens per session scan A cc07687bbe60
swift-concurrency-expert is a skill published in the GitHub repository SethCalkins/claude-ios-swift-plugin (2 stars, last pushed 7mo ago), licensed MIT. It adds 45 tokens to every session and 481 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to swift-concurrency-expert, differing in 1 line, and is treated as a copy.
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