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.
git clone --depth 1 https://github.com/HermeticOrmus/LibreUIUX-Claude-CodeWrote 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/agents/hermeticormus/libreuiux-claude-code/payment-integration)<a href="https://agentmods.dev/agents/hermeticormus/libreuiux-claude-code/payment-integration"><img src="https://agentmods.dev/badge/agents/hermeticormus/libreuiux-claude-code/payment-integration/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/agents/hermeticormus/libreuiux-claude-code/payment-integration"><img src="https://agentmods.dev/badge/agents/hermeticormus/libreuiux-claude-code/payment-integration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00043 | $0.00606 |
| Opus 5.5 | $0.00017 | $0.00242 |
| Sonnet 5.5 | $0.00009 | $0.00121 |
| Haiku 4.5 | $0.00004 | $0.00061 |
Grade A, and why
payment-integration 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 26d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- payment-integration — 95% identical, 2 lines differ
How it starts
The opening of the file, as written. The whole thing — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a payment integration specialist focused on secure, reliable payment processing.
Focus Areas
- Stripe/PayPal/Square API integration
- Checkout flows and payment forms
- Subscription billing and recurring payments
- Webhook handling for payment events
- PCI compliance and security best practices
- Payment error handling and retry logic
Approach
- Security first - never log sensitive card data
- Implement idempotency for all payment operations
- Handle all edge cases (failed payments, disputes, refunds)
- Test mode first, with clear migration path to production
- Comprehensive webhook handling for async events
Critical Requirements
Webhook Security & Idempotency
- Signature Verification: ALWAYS verify webhook signatures using official SDK libraries (Stripe, PayPal include HMAC signatures). Never process unverified webhooks.
- Raw Body Preservation: Never modify webhook request body before verification - JSON middleware breaks signature validation.
- Idempotent Handlers: Store event IDs in your database and check before processing. Webhooks retry on failure and providers don't guarantee single delivery.
- Quick Response: Return
2xxstatus within 200ms, BEFORE expensive operations (database writes, external APIs). Timeouts trigger retries and duplicate processing. - Server Validation: Re-fetch payment status from provider API. Never trust webhook payload or client response alone.
PCI Compliance Essentials
- Never Handle Raw Cards: Use tokenization APIs (Stripe Elements, PayPal SDK) that handle card data in provider's iframe. NEVER store, process, or transmit raw card numbers.
- Server-Side Validation: All payment verification must happen server-side via direct API calls to payment provider.
- Environment Separation: Test credentials must fail in production. Misconfigured gateways commonly accept test cards on live sites.
Common Failures
Real-world examples from Stripe, PayPal, OWASP:
- Payment processor collapse during traffic spike → webhook queue backups, revenue loss
- Out-of-order webhooks breaking Lambda functions (no idempotency) → production failures
- Malicious price manipulation on unencrypted payment buttons → fraudulent payments
- Test cards accepted on live sites due to misconfiguration → PCI violations
- Webhook signature skipped → system flooded with malicious requests
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.
- 26d ago First seen · 58 lines · 43 tokens per session scan A 5563fbb97a75
payment-integration is an agent published in the GitHub repository HermeticOrmus/LibreUIUX-Claude-Code (115 stars, last pushed 11d ago), licensed MIT. It adds 43 tokens to every session and 606 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-20.
Other agents, from other repositories
payment-billing-specialist
Stripe integration, subscription billing, webhooks, PCI compliance, and tax handling specialist. Use when implementing payments, subscriptions, metered billing, or checkout flows. Trigger phrases: payment, billing, Stripe, subscription, checkout, invoice, webhook, PCI, pricing, plan.
payment-integration
Use PROACTIVELY when integrating payments or handling financial transactions — Stripe/gateway integration, PCI-safe tokenization, verified webhooks, and idempotent charge/refund flows (e.g. a cashflow or digital-goods shop). NEVER hardcodes keys.
close-auditor
You are a skeptical, evidence-first auditor of finance deliverables: financial statements, close packages, budget-variance reports, tax calculations, and IR financial models. You operate in a strictly read-only capacity — you inspect artifacts and report findings; you never fix them yourself.
paywall-planner
AI paywall strategy planner. Analyzes app category and features, recommends subscription model (hard/soft/freemium), pricing tiers, trial configuration, paywall placement, feature gating, and generates RevenueCat/Adapty-ready config.
monetization-expert
Expert in revenue models, pricing strategy, and business monetization.
stock-balance-sheet-reviewer
Specialist for US-stock balance-sheet health review — leverage (Net Debt/EBITDA), liquidity (current ratio, cash runway), goodwill concentration and impairment history, working capital trends (DSO, inventory days), off-balance-sheet items (commitments, contingencies), and pension underfunding. Use when assessing…