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 twostraws/Swift-Concurrency-Agent-Skill --skill swift-concurrency-progit clone --depth 1 https://github.com/twostraws/Swift-Concurrency-Agent-SkillWrote 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/twostraws/swift-concurrency-agent-skill/swift-concurrency-pro)<a href="https://agentmods.dev/skills/twostraws/swift-concurrency-agent-skill/swift-concurrency-pro"><img src="https://agentmods.dev/badge/skills/twostraws/swift-concurrency-agent-skill/swift-concurrency-pro/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/twostraws/swift-concurrency-agent-skill/swift-concurrency-pro"><img src="https://agentmods.dev/badge/skills/twostraws/swift-concurrency-agent-skill/swift-concurrency-pro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
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 | $0.00035 | $0.01192 |
| Opus 5.5 | $0.00014 | $0.00477 |
| Sonnet 5.5 | $0.00007 | $0.00238 |
| Haiku 4.5 | $0.00003 | $0.00119 |
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 2mo 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 { This is a copy
100% identical to swift-concurrency-pro — 0 lines 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.
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:
- Scan for known-dangerous patterns using
references/hotspots.mdto prioritize what to inspect. - Check for recent Swift 6.2 concurrency behavior using
references/new-features.md. - Validate actor usage for reentrancy and isolation correctness using
references/actors.md. - Ensure structured concurrency is preferred over unstructured where appropriate using
references/structured.md. - Check unstructured task usage for correctness using
references/unstructured.md. - Verify cancellation is handled correctly using
references/cancellation.md. - Validate async stream and continuation usage using
references/async-streams.md. - Check bridging code between sync and async worlds using
references/bridging.md. - Review any legacy concurrency migrations using
references/interop.md. - Cross-check against common failure modes using
references/bug-patterns.md. - If the project has strict-concurrency errors, map diagnostics to fixes using
references/diagnostics.md. - 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/awaitand closure-based variants, always preferasync/await. - Do not introduce third-party concurrency frameworks without asking first.
- Do not suggest
@unchecked Sendableto fix compiler errors. It silences the diagnostic without fixing the underlying race. Prefer actors, value types, orsendingparameters instead. The only legitimate use is for types with internal locking that are provably thread-safe.
What ships with it
18 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.
- .claude-plugin/plugin.json 417 B
- agents/openai.yaml 380 B
- assets/swift-concurrency-pro-icon.png 2.7 KB
- assets/swift-concurrency-pro-icon.svg 1.5 KB
- references/actors.md 5.4 KB
- references/async-streams.md 2.1 KB
- references/bridging.md 2.9 KB
- references/bug-patterns.md 4.1 KB
- references/cancellation.md 3.6 KB
- references/diagnostics.md 4.4 KB
- references/hotspots.md 2.3 KB
- references/interop.md 3.6 KB
- references/new-features.md 7.7 KB
- references/structured.md 3.0 KB
- references/testing.md 8.1 KB
- references/unstructured.md 2.4 KB
- skills/swift-concurrency-pro/references 16 B
- skills/swift-concurrency-pro/SKILL.md 5.9 KB
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.
- 2mo ago First seen · 125 lines · 35 tokens per session scan A 95d3098b038a
swift-concurrency-pro is a skill published in the GitHub repository twostraws/Swift-Concurrency-Agent-Skill (582 stars, last pushed 5mo ago), licensed MIT. It adds 35 tokens to every session and 1,192 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). It is 100% identical to swift-concurrency-pro, differing in 0 lines, and is treated as a copy.
swift-concurrency-pro compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| swift-concurrency-protwostraws/Swift-Concurrency-Agent-Skill | Skill | 582 | 5mo ago | MIT | A | 35 | Claude Code, Codex |
| axiom-audit-codableCharlesWiltgen/Axiom | Skill | 1.3k | yesterday | MIT | A | 32 | Codex |
| axiom-swift-simplifierCharlesWiltgen/Axiom | Skill | 1.3k | yesterday | MIT | A | 34 | Codex |
| coding-best-practicesrshankras/claude-code-apple-skills | Skill | 864 | 2d ago | MIT | A | 55 | Claude Code |
| kotlin-concurrency-and-flowchrisbanes/skills | Skill | 1.1k | yesterday | Apache-2.0 | A | 60 | Claude Code |
| kotlin-api-designchrisbanes/skills | Skill | 1.1k | yesterday | Apache-2.0 | A | 46 | Claude Code |
| swift-concurrency-reviewcharlesjones-dev/claude-code-plugins-dev | Skill | 35 | 27d ago | MIT | A | 94 | Claude Code |