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 n0an/Swift-FormatStyle-Agent-Skill --skill swift-format-stylegit clone --depth 1 https://github.com/n0an/Swift-FormatStyle-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/n0an/swift-formatstyle-agent-skill/swift-format-style)<a href="https://agentmods.dev/skills/n0an/swift-formatstyle-agent-skill/swift-format-style"><img src="https://agentmods.dev/badge/skills/n0an/swift-formatstyle-agent-skill/swift-format-style/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/n0an/swift-formatstyle-agent-skill/swift-format-style"><img src="https://agentmods.dev/badge/skills/n0an/swift-formatstyle-agent-skill/swift-format-style.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 | $0.00050 | $0.00955 |
| Opus 5 | $0.00025 | $0.00477 |
| Sonnet 5 | $0.00010 | $0.00191 |
| Haiku 4.5 | $0.00005 | $0.00096 |
Grade A, and why
swift-format-style 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 9d 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 — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Write and review Swift code that formats values for display, ensuring modern FormatStyle APIs are used instead of legacy Formatter subclasses or C-style formatting.
Review process:
- Check for legacy formatting patterns and replace with modern FormatStyle equivalents using
references/anti-patterns.md. - Validate number, percent, and currency formatting using
references/numeric-styles.md. - Validate date and time formatting using
references/date-styles.md. - Validate duration formatting using
references/duration-styles.md. - Validate measurement, list, person name, byte count, and URL formatting using
references/other-styles.md. - Check SwiftUI Text views for proper FormatStyle integration using
references/swiftui.md.
If doing partial work, load only the relevant reference files.
Core Instructions
- Target iOS 15+ / macOS 12+ minimum for basic FormatStyle. Duration and URL styles require iOS 16+ / macOS 13+.
- Never use legacy
Formattersubclasses (DateFormatter,NumberFormatter,MeasurementFormatter,DateComponentsFormatter,DateIntervalFormatter,PersonNameComponentsFormatter,ByteCountFormatter). - Never use C-style
String(format:)for number formatting. Always use.formatted()orFormatStyledirectly. - Never use
DispatchQueuefor formatting on background threads - FormatStyle types are value types and thread-safe. - Prefer
.formatted()instance method for simple cases, and explicitFormatStyletypes for reusable or complex configurations. - In SwiftUI, use
Text(_:format:)instead ofText("\(value.formatted())"). - Use
Decimalinstead ofFloat/Doublefor currency values. - FormatStyle types are locale-aware by default. Only set locale explicitly when you need a specific locale different from the user's current locale.
- FormatStyle types conform to
CodableandHashable, making them safe to store and compare.
Output Format
If the user asks for a review, organize findings by file. For each issue:
What ships with it
7 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.
- 9d ago First seen · 91 lines · 50 tokens per session scan A 8a4983d20be3
swift-format-style is a skill published in the GitHub repository n0an/Swift-FormatStyle-Agent-Skill (9 stars, last pushed yesterday), licensed MIT. It adds 50 tokens to every session and 955 once invoked, about $0.0003 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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