subscription-patterns

A set of implementation patterns for subscription billing across the full customer lifecycle, including trials, discounts, plan changes, failed payments, cancellations, and add-ons. Subscription billing is recurring payment management for plans customers pay for over time.

In plain words
What is it for?
Use it when building free trials, introductory offers, plan changes, proration, payment retries, cancellation flows, plan groups, or subscription add-ons.
Why use it?
It provides consistent rules for handling subscription states and transitions, including payment problems and upgrades or downgrades. The patterns are intended to apply across billing systems.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/commet-labs/subscription-patterns/subscription-patterns
Any agent
npx skills add commet-labs/subscription-patterns --skill subscription-patterns
Clone the repo
git clone --depth 1 https://github.com/commet-labs/subscription-patterns

Made for: Claude Code, Codex.

Per session 51 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 667 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00051 $0.00667
Opus 5 $0.00026 $0.00333
Sonnet 5 $0.00010 $0.00133
Haiku 4.5 $0.00005 $0.00067

Measured 2d ago against content hash a8c5cd3e09e2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

subscription-patterns 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 2d 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/subscription-patterns/SKILL.md · 54 lines

How it starts

The opening of the file, as written. The whole thing — 54 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Subscription Billing Patterns

Universal patterns for the full subscription lifecycle. These apply to any billing system — the examples use @commet/node but the logic is the same everywhere.

Subscription State Machine

Every subscription moves through these states:

draft → pending_payment → trialing → active → canceled
                               │          │
                               └──────────┴→ past_due
                                              │
                                              ├→ active
                                              └→ canceled

The persisted statuses are draft, pending_payment, trialing, active, past_due, and canceled. Commet does not expose a pause/resume status.

One active subscription relationship per customer. Treat the active endpoint and current API errors as the source of truth when deciding whether a new subscription may be created. Do not recreate lifecycle rules from stale status lists.

Quick Reference

Task File
Implement free trials trials-and-intro-offers.md
Add intro offer discounts trials-and-intro-offers.md
Handle plan upgrades upgrades-downgrades.md
Handle plan downgrades upgrades-downgrades.md
Change billing interval upgrades-downgrades.md
Calculate proration proration-logic.md
Handle mid-cycle plan changes proration-logic.md
Implement failed payment retries dunning-and-retries.md
Build grace period logic dunning-and-retries.md
Cancel a subscription cancellation-flows.md
Reactivate a canceled subscription cancellation-flows.md
Add purchasable add-ons addons-and-extras.md
Prorate mid-cycle add-on activation addons-and-extras.md

Read the full file on GitHub · 54 lines

Files

What ships with it

6 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.

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. 2d ago First seen · 54 lines · 51 tokens per session scan A a8c5cd3e09e2

Subscribe to this mod's changes

subscription-patterns is a skill published in the GitHub repository commet-labs/subscription-patterns (2 stars, last pushed 1mo ago), licensed MIT. It adds 51 tokens to every session and 667 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 2026-08-31.

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