polar-billing

polar-billing is a skill for Claude Code from fcakyon/claude-codex-settings. It costs 29 tokens per session (5,661 once invoked), scanned A, original, Apache-2.0.

A guide to building Polar's billing system, including payments, orders, recurring subscriptions, and customer benefits. Polar is a billing platform that uses Stripe for payment processing.

In plain words
What is it for?
Use it when working on Polar checkout flows, Stripe integration, subscription changes, proration, payment retries, transaction records, or benefit provisioning.
Why use it?
It gives developers a shared explanation of how billing records and payment events connect across the subscription lifecycle. This reduces mistakes when changing checkout, payments, retries, or benefits.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the polar-skills plugin — 2 skills shipped together

Good fit Use it when working on Polar checkout flows, Stripe integration, subscription changes, proration, payment retries, transaction records, or benefit provisioning.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fcakyon/claude-codex-settings/polar-billing
About the project

claude-codex-settings is a collection of configurations and reusable extensions for Claude Code, OpenAI Codex, Cursor, and related coding tools. Developers use its skills, commands, hooks, agents, plugins, and MCP servers to shape coding-agent workflows and connect alternative model APIs. The catalogue entries are components of this collection that can be installed into supported coding tools.

fcakyon/claude-codex-settings · 1,133 stars · on GitHub · claudesettings.com

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 fcakyon/claude-codex-settings --skill polar-billing
Clone the repo
git clone --depth 1 https://github.com/fcakyon/claude-codex-settings

Made for: Claude Code.

Or install polar-skills, the plugin that ships this one along with the rest of its 2 skills.

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 polar-billing

README.md
[![agentmods](https://agentmods.dev/badge/skills/fcakyon/claude-codex-settings/polar-billing.svg)](https://agentmods.dev/skills/fcakyon/claude-codex-settings/polar-billing)
Your own site
<a href="https://agentmods.dev/skills/fcakyon/claude-codex-settings/polar-billing"><img src="https://agentmods.dev/badge/skills/fcakyon/claude-codex-settings/polar-billing.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,661 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 $0.00029 $0.05661
Opus 5 $0.00015 $0.02831
Sonnet 5 $0.00006 $0.01132
Haiku 4.5 $0.00003 $0.00566

Measured 5d ago against content hash 29e8b87d2468, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

polar-billing 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 5d 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.

plugins/polar-skills/skills/polar-billing/SKILL.md · 822 lines

How it starts

The opening of the file, as written. The whole thing — 822 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Polar Billing System

Comprehensive guide to Polar's billing infrastructure, covering entities, flows, Stripe integration, and benefit provisioning.

Quick Reference

Checkout → Payment → Order → Transaction → Benefits
                         ↓
                   Subscription (if recurring)
                         ↓
                   Subscription Cycle → Order → ...

Table of Contents

  1. Core Entities
  2. Entity Relationships
  3. Main Services
  4. Dramatiq Background Tasks
  5. Stripe Integration
  6. Subscription Lifecycle
  7. Proration System
  8. Benefits & Credits
  9. Dunning & Payment Retry
  10. Transaction Ledger
  11. Key File Locations

1. Core Entities

Checkout

File: server/polar/models/checkout.py

Shopping cart/payment session before order confirmation.

Field Type Description
status CheckoutStatus open, expired, confirmed, succeeded, failed
payment_processor PaymentProcessor stripe, manual
client_secret str Unique identifier for frontend
amount, currency int, str Price in cents
tax_amount, discount_amount int Calculated amounts
allow_trial, trial_end bool, datetime Trial configuration
seats int For seat-based products

Relationships: organization, customer, product, product_price, discount, subscription (for upgrades)


CheckoutLink

File: server/polar/models/checkout_link.py

Persistent URL that creates Checkout Sessions on visit.

Field Type Description
client_secret str Unique identifier for the URL
seats int | None Preconfigured seat count for seat-based pricing
discount_id UUID | None Preset discount to apply
trial_interval, trial_interval_count Trial config Override product trial settings

Read the full file on GitHub · 822 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.

  1. 5d ago First seen · 822 lines · 29 tokens per session scan A 29e8b87d2468

Subscribe to this mod's changes

polar-billing is a skill published in the GitHub repository fcakyon/claude-codex-settings (1,133 stars, last pushed 2d ago), licensed Apache-2.0. It adds 29 tokens to every session and 5,661 once invoked, about $0.0001 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.