What is axiom-storekit-ref?

A reference for StoreKit 2, Apple’s framework for selling digital items and subscriptions inside apps. It covers products, purchases, transaction verification, and subscription states.

Use it to build consumable purchases, one-time unlocks, subscriptions, purchase flows, transaction checks, and StoreKit-based SwiftUI screens.

It helps developers implement purchases correctly, including restoring permanent products and subscriptions on new devices.

axiom-storekit-ref — Skill for Claude Code and Codex by ComeOnOliver

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 ComeOnOliver/skillshub --skill axiom-storekit-ref

Clone the repo

git clone --depth 1 https://github.com/ComeOnOliver/skillshub

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/comeonoliver/skillshub/axiom-storekit-ref/github.svg)](https://agentmods.dev/skills/comeonoliver/skillshub/axiom-storekit-ref)

Your own site

<a href="https://agentmods.dev/skills/comeonoliver/skillshub/axiom-storekit-ref"><img src="https://agentmods.dev/badge/skills/comeonoliver/skillshub/axiom-storekit-ref/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/comeonoliver/skillshub/axiom-storekit-ref"><img src="https://agentmods.dev/badge/skills/comeonoliver/skillshub/axiom-storekit-ref.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 8,682 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00056	$0.08682
Opus 5	$0.00028	$0.04341
Sonnet 5	$0.00011	$0.01736
Haiku 4.5	$0.00006	$0.00868

Measured 9d ago against content hash ba9e385f61ec, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

axiom-storekit-ref 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.

skills/CharlesWiltgen/Axiom/axiom-storekit-ref/SKILL.md · 1,562 lines

How it starts

The opening of the file, as written. The whole thing — 1,562 lines — stays where its author put it; the contents beside it link to each section on GitHub.

StoreKit 2 — Complete API Reference

Overview

StoreKit 2 is Apple's modern in-app purchase framework with async/await APIs, automatic receipt validation, and SwiftUI integration. This reference covers every API, iOS 18.4 enhancements, and comprehensive WWDC 2025 code examples.

Product Types Supported

Consumable:

Products that can be purchased multiple times
Examples: coins, hints, temporary boosts
Do NOT restore on new devices

Non-Consumable:

Products purchased once, owned forever
Examples: premium features, level packs, remove ads
MUST restore on new devices

Auto-Renewable Subscription:

Subscriptions that renew automatically
Organized into subscription groups
MUST restore on new devices
Support: free trials, intro offers, promotional offers, win-back offers

Non-Renewing Subscription:

Fixed duration subscriptions (no auto-renewal)
Examples: seasonal passes
MUST restore on new devices

Key Improvements Over StoreKit 1

Async/Await: Modern concurrency instead of delegates/closures
Automatic Verification: JSON Web Signature (JWS) verification built-in
Transaction Types: Strong Swift types instead of SKPaymentTransaction
Testing: StoreKit configuration files for local testing
SwiftUI Views: Pre-built purchase UIs (ProductView, SubscriptionStoreView)
Server APIs: App Store Server API and Server Notifications

When to Use This Reference

Use this reference when:

Implementing in-app purchases with StoreKit 2
Understanding new iOS 18.4 fields (appTransactionID, offerPeriod, etc.)
Looking up specific API signatures and parameters
Planning subscription architecture
Debugging transaction issues
Implementing StoreKit Views
Integrating with App Store Server APIs

Related Skills:

axiom-in-app-purchases — Discipline skill with testing-first workflow, architecture patterns
(Future: iap-auditor agent for auditing existing IAP code)
(Future: iap-implementation agent for implementing IAP from scratch)

Read the full file on GitHub · 1,562 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.

9d ago First seen · 1,562 lines · 56 tokens per session scan A ba9e385f61ec

Subscribe to this mod's changes

axiom-storekit-ref is a skill published in the GitHub repository ComeOnOliver/skillshub (63 stars, last pushed 2mo ago), licensed MIT. It adds 56 tokens to every session and 8,682 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 2026-09-03.

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