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.
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 CharlesWiltgen/Axiom --skill axiom-paymentsgit clone --depth 1 https://github.com/CharlesWiltgen/AxiomWrote 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/charleswiltgen/axiom/axiom-payments)<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-payments"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-payments/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/charleswiltgen/axiom/axiom-payments"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-payments.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk warn
- NVIDIA SkillSpector warn
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 Privilege Escalation · line 131 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
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 | $0.00055 | $0.03731 |
| Opus 5 | $0.00028 | $0.01865 |
| Sonnet 5 | $0.00011 | $0.00746 |
| Haiku 4.5 | $0.00006 | $0.00373 |
Grade A, and why
axiom-payments 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.
How it starts
The opening of the file, as written. The whole thing — 228 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Real-World Payments (Apple Pay / Wallet / Tap to Pay)
You MUST use this skill when accepting ANY real-world payment — physical goods, services, donations, ticketing, loyalty cards, contactless card-present, or post-purchase order tracking. NOT for in-app purchase or digital content.
When to Use
Use this skill when you encounter:
- Adding Apple Pay to an iOS / iPadOS / macOS / Catalyst / visionOS / watchOS app
- Adding Apple Pay to a website (Apple Pay JS or W3C Payment Request API)
- Building Wallet passes (boarding passes, event tickets, coupons, loyalty cards, store cards)
- Accepting contactless card payments on iPhone (Tap to Pay on iPhone / ProximityReader)
- Surfacing post-purchase order tracking in Wallet (Orders in Wallet, FinanceKitUI add-order helpers)
- Issuer or bank card provisioning into Wallet (issuer extensions)
- Apple Pay merchant ID, processing certificate, or merchant identity certificate setup
- Pass Type ID or Order Type ID certificates and PKCS #7 signing chains
- Tap to Pay managed entitlement (
com.apple.developer.proximity-reader.payment.acceptance) - App Review rejections that mention payments, IAP, Apple Pay, Wallet, or Acceptable Use Guidelines
- Domain verification for Apple Pay on the web (
.well-known/apple-developer-merchantid-domain-association.txt) - Sandbox testing with Apple Pay sandbox cards or sandbox tester accounts
When NOT to Use
| Issue | Correct Skill | Why NOT axiom-payments |
|---|---|---|
| In-app purchase, subscriptions for digital content | axiom-integration | StoreKit 2 / digital goods boundary; see axiom-integration (skills/in-app-purchases.md) |
| Generic NFC tag reads (Core NFC, non-Wallet) | axiom-integration | Different framework; PassKit NFC is Wallet-specific |
| Code signing / provisioning fundamentals | axiom-security | Code signing is generic; payment certs are added to that flow |
| App Store rejection workflow & appeals | axiom-shipping | Rejection workflow lives there; payment-specific rejection patterns route from there into here |
| HIG cross-cutting design guidance | axiom-design | Apple Pay / Wallet HIG specifics live here, but design overview lives in axiom-design |
| Consumer banking surface (FinanceKit) | Out of scope | This suite uses FinanceKitUI only for Orders. Account aggregation / transaction queries are not covered. |
| PKSecureElementPass, transit cards, car keys | Out of scope | Issuer-controlled, not relevant to merchant developers |
What ships with it
12 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.
- skills/apple-pay-ref.md 20 KB
- skills/apple-pay-vs-iap.md 17 KB
- skills/apple-pay-web-ref.md 16 KB
- skills/apple-pay-web.md 30 KB
- skills/apple-pay.md 25 KB
- skills/payments-diag.md 23 KB
- skills/tap-to-pay-ref.md 14 KB
- skills/tap-to-pay.md 20 KB
- skills/wallet-extensions-ref.md 3.1 KB
- skills/wallet-orders.md 18 KB
- skills/wallet-passes-ref.md 21 KB
- skills/wallet-passes.md 23 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.
- 6d ago First seen · 228 lines · 55 tokens per session scan A 87cb7f2442e2
axiom-payments is a skill published in the GitHub repository CharlesWiltgen/Axiom (1,155 stars, last pushed 3d ago), licensed MIT. It adds 55 tokens to every session and 3,731 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 2026-09-06.
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User-facing sign-in for a fintech iOS app, built on Apple's AuthenticationServices (ASAuthorization, ASWebAuthenticationSession) and LocalAuthentication (LAContext). Targets the iOS 26 era. This skill covers how the user proves identity; storing the resulting tokens/keys is a separate concern.