swift-formatstyle

swift-formatstyle is a skill for Claude Code, Codex from TalissonVitorino/kmp-ios-skills. It costs 226 tokens per session (5,550 once invoked), scanned A, original, MIT.

A guide to formatting values such as numbers, currencies, dates, durations, measurements, and names according to the user's locale. It also covers parsing formatted text back into values.

In plain words
What is it for?
Use it for prices, percentages, dates, amounts, durations, measurements, file sizes, and other localized text in Apple-platform apps.
Why use it?
It helps display values correctly for different languages and regions while replacing older formatter classes with Swift's newer type-safe system.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it for prices, percentages, dates, amounts, durations, measurements, file sizes, and other localized text in Apple-platform apps.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/talissonvitorino/kmp-ios-skills/swift-formatstyle
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 TalissonVitorino/kmp-ios-skills --skill swift-formatstyle
Clone the repo
git clone --depth 1 https://github.com/TalissonVitorino/kmp-ios-skills

Made for: Claude Code, 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-formatstyle

README.md
[![agentmods](https://agentmods.dev/badge/skills/talissonvitorino/kmp-ios-skills/swift-formatstyle/github.svg)](https://agentmods.dev/skills/talissonvitorino/kmp-ios-skills/swift-formatstyle)
Your own site
<a href="https://agentmods.dev/skills/talissonvitorino/kmp-ios-skills/swift-formatstyle"><img src="https://agentmods.dev/badge/skills/talissonvitorino/kmp-ios-skills/swift-formatstyle/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.

agentmods 80×15 button for swift-formatstyle

Your own site · 80×15
<a href="https://agentmods.dev/skills/talissonvitorino/kmp-ios-skills/swift-formatstyle"><img src="https://agentmods.dev/badge/skills/talissonvitorino/kmp-ios-skills/swift-formatstyle.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 226 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,550 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
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 $0.00226 $0.05550
Opus 5 $0.00113 $0.02775
Sonnet 5 $0.00045 $0.01110
Haiku 4.5 $0.00023 $0.00555

Measured 7d ago against content hash 46acd68fecc0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

swift-formatstyle 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 7d 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.

ios/swift-formatstyle/SKILL.md · 401 lines

How it starts

The opening of the file, as written. The whole thing — 401 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Swift FormatStyle (iOS / macOS)

Locale-aware, value-to-string formatting (and string-to-value parsing) built on Foundation's FormatStyle protocol. This is the modern, type-safe replacement for NumberFormatter, DateFormatter, DateComponentsFormatter, and friends — prefer it for all new code.

  • Baseline availability: FormatStyle, number/date/list/measurement/person-name styles are iOS 15+. Duration styles (.units / .time) and the FormatStyle-based ByteCountFormatStyle (.byteCount) are iOS 16+.
  • KMP boundary: keep the numeric value (a Decimal, Date, or Money) in shared code; format only at the iOS presentation layer. Never hand a Double across the boundary for money — see kmp-money.
  • Two entry points, equivalent:
    • value.formatted(style) — call on the value.
    • style.format(value) — call on the style (useful when the style is stored/reused).

Contents

Core protocol & the .formatted entry points

A FormatStyle maps FormatInput → FormatOutput (usually String) via format(_:), and applies locale conventions automatically. Every built-in style is a value type you build with dot-chained modifiers.

import Foundation

let n = 1234.5
n.formatted()                                   // "1,234.5"  (current locale)
n.formatted(.number.precision(.fractionLength(2)))   // "1,234.50"
(0.75).formatted(.percent)                      // "75%"
Date.now.formatted(.dateTime.year().month().day())   // "Aug 3, 2026" (en_US)

Read the full file on GitHub · 401 lines

Files

What ships with it

1 file 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.

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. 7d ago First seen · 401 lines · 226 tokens per session scan A 46acd68fecc0

Subscribe to this mod's changes

swift-formatstyle is a skill published in the GitHub repository TalissonVitorino/kmp-ios-skills (12 stars, last pushed 16d ago), licensed MIT. It adds 226 tokens to every session and 5,550 once invoked, about $0.0011 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 2026-09-03.

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