axiom-modernize

axiom-modernize is a skill for Claude Code, Codex from CharlesWiltgen/Axiom. It costs 48 tokens per session (3,807 once invoked), scanned A, original, MIT.

A modernization helper for SwiftUI apps that finds older Swift and SwiftUI patterns and suggests current iOS 17 and iOS 18 forms. SwiftUI is Apple's framework for building app interfaces in Swift.

In plain words
What is it for?
Use it to migrate ObservableObject and related state patterns, replace older SwiftUI modifiers, and change completion-handler code to async/await.
Why use it?
It helps reduce the manual work of updating older state management, view modifiers, and asynchronous code to newer APIs.

Skill for Claude CodeCodex

Written for Claude Code and Codex: Claude Code plugin machinery, but also agents/openai.yaml present.

Good fit Use it to migrate ObservableObject and related state patterns, replace older SwiftUI modifiers, and change completion-handler code to async/await.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/charleswiltgen/axiom/axiom-modernize
About the project

Axiom is a toolkit of instructions, agents, commands, and development tools that give coding assistants specialized guidance for Apple operating-system development. It covers Swift, SwiftUI, interface design, data, concurrency, performance, networking, accessibility, logging, crash analysis, simulator testing, and profiling for iOS, iPadOS, watchOS, and tvOS. The catalogue contains 42 agents, 16 commands, and one plugin from this toolkit.

CharlesWiltgen/Axiom · 1,155 stars · on GitHub · charleswiltgen.github.io

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 CharlesWiltgen/Axiom --skill axiom-modernize
Clone the repo
git clone --depth 1 https://github.com/CharlesWiltgen/Axiom

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 axiom-modernize

README.md
[![agentmods](https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-modernize/github.svg)](https://agentmods.dev/skills/charleswiltgen/axiom/axiom-modernize)
Your own site
<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-modernize"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-modernize/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 axiom-modernize

Your own site · 80×15
<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-modernize"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-modernize.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,807 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 warn 7 Sept 2026
SkillSpector: 1 finding, up to high

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 →

  • high Anti-Refusal · line 90
    Skill instructs the agent to omit warnings, disclaimers, or ethical commentary. Stripping safety caveats hides risk from the user and is a common jailbreak preamble.
    Fix: Remove instructions that suppress warnings, disclaimers, or ethical commentary. Let the agent surface safety-relevant caveats to the user.
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 $0.00048 $0.03807
Opus 5 $0.00024 $0.01903
Sonnet 5 $0.00010 $0.00761
Haiku 4.5 $0.00005 $0.00381

Measured 6d ago against content hash 76f91aac84bd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

axiom-modernize 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 6d 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.

axiom-codex/skills/axiom-modernize/SKILL.md · 569 lines

How it starts

The opening of the file, as written. The whole thing — 569 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Modernization Helper Agent

You are an expert at migrating iOS apps to modern iOS 17/18+ patterns.

Your Mission

Scan the codebase for legacy patterns and provide migration paths:

  • ObservableObject@Observable
  • @StateObject@State with Observable
  • @ObservedObject → Direct property or @Bindable
  • @EnvironmentObject@Environment
  • Legacy SwiftUI modifiers → Modern equivalents
  • Completion handlers → async/await

Tool Use Is Mandatory

Run every Glob, Grep, and Read this prompt lists. Do not reason from training data instead of scanning.

  • Run each Grep pattern as written; do not collapse them into one mega-regex.
  • Run the Read verifications each section calls for.
  • "Build a mental model" / "map the architecture" means with tool output in hand, not from memory.

Files to Scan

Swift files: **/*.swift Skip: *Tests.swift, *Previews.swift, */Pods/*, */Carthage/*, */.build/*, */DerivedData/*, */scratch/*, */docs/*, */.claude/*, */.claude-plugin/*

Modernization Patterns (iOS 17+ / iOS 18+)

Pattern 1: ObservableObject → @Observable (HIGH)

Why migrate: Better performance (view updates only when accessed properties change), simpler syntax, no @Published needed

Requirement: iOS 17+

Detection:

Grep: class.*ObservableObject
Grep: : ObservableObject
Grep: @Published
// ❌ LEGACY (iOS 14-16)
class ContentViewModel: ObservableObject {
    @Published var items: [Item] = []
    @Published var isLoading = false
    @Published var errorMessage: String?
}

// ✅ MODERN (iOS 17+)
@Observable
class ContentViewModel {
    var items: [Item] = []
    var isLoading = false
    var errorMessage: String?

    // Use @ObservationIgnored for non-observed properties
    @ObservationIgnored
    var internalCache: [String: Any] = [:]
}

Migration steps:

  1. Replace : ObservableObject with @Observable macro
  2. Remove all @Published property wrappers
  3. Add @ObservationIgnored to properties that shouldn't trigger updates
  4. Update consuming views (see patterns below)

Read the full file on GitHub · 569 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. 6d ago First seen · 569 lines · 48 tokens per session scan A 76f91aac84bd

Subscribe to this mod's changes

axiom-modernize is a skill published in the GitHub repository CharlesWiltgen/Axiom (1,155 stars, last pushed 3d ago), licensed MIT. It adds 48 tokens to every session and 3,807 once invoked, about $0.0002 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 2026-09-06.

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