swift-concurrency-pro

swift-concurrency-pro is a skill for Codex from jacklandrin/OnlySwitch. It costs 35 tokens per session (1,192 once invoked), scanned A, original, MIT.

A review guide for Swift code that uses concurrency, meaning work that can happen asynchronously or at the same time. It checks modern APIs, async/await usage, actors, cancellation, streams, and related code patterns.

In plain words
What is it for?
Use it when writing or reviewing Swift concurrency code, investigating strict-concurrency errors, or checking code that bridges synchronous and asynchronous operations.
Why use it?
Concurrency code can fail through data races, incorrect isolation, lost cancellation, or unsafe task handling. The review focuses on genuine correctness problems rather than style complaints.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Use it when writing or reviewing Swift concurrency code, investigating strict-concurrency errors, or checking code that bridges synchronous and asynchronous operations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jacklandrin/onlyswitch/swift-concurrency-pro
About the project

OnlySwitch is a macOS menu bar app that groups system toggles and shortcuts in one customizable control panel. It is used to change settings such as dark mode, desktop icon visibility, notch hiding, and audio controls, with optional widgets and keyboard shortcuts.

jacklandrin/OnlySwitch · 5,907 stars · on GitHub · onlyswitch.click

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 jacklandrin/OnlySwitch --skill swift-concurrency-pro
Clone the repo
git clone --depth 1 https://github.com/jacklandrin/OnlySwitch

Made for: 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 swift-concurrency-pro

README.md
[![agentmods](https://agentmods.dev/badge/skills/jacklandrin/onlyswitch/swift-concurrency-pro.svg)](https://agentmods.dev/skills/jacklandrin/onlyswitch/swift-concurrency-pro)
Your own site
<a href="https://agentmods.dev/skills/jacklandrin/onlyswitch/swift-concurrency-pro"><img src="https://agentmods.dev/badge/skills/jacklandrin/onlyswitch/swift-concurrency-pro.svg" alt="Measured on agentmods" height="20"></a>
Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,192 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 37
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
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 $0.00035 $0.01192
Opus 5 $0.00017 $0.00596
Sonnet 5 $0.00007 $0.00238
Haiku 4.5 $0.00003 $0.00119

Measured 8d ago against content hash 95d3098b038a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

swift-concurrency-pro 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.

func fetch(_ key: String) async throws -> Data {
Origin

Copies of this mod

2 near-identical copies found in the catalogue:

doc/skills/swift-concurrency-pro/SKILL.md · 125 lines

How it starts

The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Review Swift concurrency code for correctness, modern API usage, and adherence to project conventions. Report only genuine problems - do not nitpick or invent issues.

Review process:

  1. Scan for known-dangerous patterns using references/hotspots.md to prioritize what to inspect.
  2. Check for recent Swift 6.2 concurrency behavior using references/new-features.md.
  3. Validate actor usage for reentrancy and isolation correctness using references/actors.md.
  4. Ensure structured concurrency is preferred over unstructured where appropriate using references/structured.md.
  5. Check unstructured task usage for correctness using references/unstructured.md.
  6. Verify cancellation is handled correctly using references/cancellation.md.
  7. Validate async stream and continuation usage using references/async-streams.md.
  8. Check bridging code between sync and async worlds using references/bridging.md.
  9. Review any legacy concurrency migrations using references/interop.md.
  10. Cross-check against common failure modes using references/bug-patterns.md.
  11. If the project has strict-concurrency errors, map diagnostics to fixes using references/diagnostics.md.
  12. If reviewing tests, check async test patterns using references/testing.md.

If doing a partial review, load only the relevant reference files.

Core Instructions

  • Target Swift 6.2 or later with strict concurrency checking.
  • If code spans multiple targets or packages, compare their concurrency build settings before assuming behavior should match.
  • Prefer structured concurrency (task groups) over unstructured (Task {}).
  • Prefer Swift concurrency over Grand Central Dispatch for new code. GCD is still acceptable in low-level code, framework interop, or performance-critical synchronous work where queues and locks are the right tool – don't flag these as errors.
  • If an API offers both async/await and closure-based variants, always prefer async/await.
  • Do not introduce third-party concurrency frameworks without asking first.
  • Do not suggest @unchecked Sendable to fix compiler errors. It silences the diagnostic without fixing the underlying race. Prefer actors, value types, or sending parameters instead. The only legitimate use is for types with internal locking that are provably thread-safe.

Read the full file on GitHub · 125 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 · 125 lines · 35 tokens per session scan A 95d3098b038a

Subscribe to this mod's changes

swift-concurrency-pro is a skill published in the GitHub repository jacklandrin/OnlySwitch (5,907 stars, last pushed 8d ago), licensed MIT. It adds 35 tokens to every session and 1,192 once invoked, about $0.0002 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 2026-08-30.

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