Purchase thanks

The homepage Trigger it card labeled Event is this example. A purchase is a moment your factory can already know about. The package that reacts does not need a model in the loop and does not need you to paste the receipt into chat.

Live public package: @kentcdodds/stripe-purchase-thanks. After a verified successful Stripe checkout it indexes Kent's business Gmail for the buyer, creates a thank-you draft on a relevant thread (To is the buyer, never Kent), and posts a one-liner that the draft is ready. Draft only. Never send.

The homepage calls this an event because the interesting fact is the purchase, not the HTTP door. Kent's listing uses a Stripe webhook as the way that fact arrives, then treats the verified checkout as the event that starts the thank-you. You can also emit @you/purchase.completed from one package and subscribe from another.

Subscriptions and package-emitted topics: Subscriptions and events. Vendor POST ingress: Inbound webhooks. Drafts the agent must not send: Gmail drafts without send.

Two honest shapes

One package, vendor ingress. Stripe POSTs checkout.session.completed. The handler fetch-back verifies the event id (the body is untrusted; only id is used), keeps successful paid checkouts, and calls thankPurchase. That is Kent's listing.

import handleStripeWebhook from 'kody:@you/stripe-purchase-thanks/handle-stripe-webhook'

export default async function main() {
	return await handleStripeWebhook({
		request: { json: { id: 'evt_1ABC', type: 'checkout.session.completed' } },
	})
}

Two packages, an owned topic. The Stripe (or commerce) package verifies the payment, then emits. The thanks package subscribes. Other packages can listen without sharing the webhook secret.

import { events } from 'kody:runtime'

await events.dispatch({
	topic: '@you/purchase.completed',
	idempotencyKey: `stripe:checkout:${eventId}`,
	payload: {
		eventId,
		product: 'Kody Standard',
		customerEmail: 'ada@example.com',
	},
})

{
	"name": "@you/purchase-thanks",
	"kody": {
		"subscriptions": {
			"@you/purchase.completed": {
				"handler": "./src/on-purchase-completed.ts",
				"description": "Draft a thank-you after a verified purchase."
			}
		}
	}
}

events.dispatch is unavailable in ad hoc execute. Emit from package code (or a static import of an export that dispatches). Payloads are JSON objects capped at 64 KiB. Store Gmail threads and draft ids in packageStorage() and emit a reference when the thank-you record is large.

Package shape

Kent's thank-you export is the part you replay from chat after a payment is already verified:

import { thankPurchase } from 'kody:@you/stripe-purchase-thanks/thank-purchase'

export default async function main() {
	return await thankPurchase({
		eventId: 'evt_1ABC',
		amount: 1200,
		currency: 'usd',
		product: 'Kody Standard',
		customerName: 'Ada',
		customerEmail: 'ada@example.com',
		livemode: true,
	})
}

Rules that keep this safe:

• Fetch-back verify. Do not trust the webhook JSON beyond the event id.
• Draft. Do not send. If the Google token can send, lock the published package and the integration so execute cannot widen it. See Gmail drafts without send.
• Money alerts stay out of this package. Kent keeps those in @kentcdodds/stripe-alerts.
• Never log customer email, checkout session ids, or receipt URLs in public channels.
• After publish, smoke-test the webhook export with a dry-run payload, or replay thankPurchase on facts you already verified. For the owned-topic shape, use packageSubscriptionDispatch.

Example prompts

Build the event shape

Search Kody for purchase thanks and package-emitted events. I want @me/purchase.completed emitted after a verified paid checkout, and a second package that drafts a thank-you (never send) when that event lands. Show me the kody.emits and kody.subscriptions snippets, then persist both packages. Smoke-test the subscriber with packageSubscriptionDispatch.

Fork the public one

Open https://kody.codes/@kentcdodds/stripe-purchase-thanks, fork it, and point the Stripe webhook at my checkout. Keep drafts-only. Do not send. Do not disable Kent's live stripe webhook.

Replay one purchase

Import thankPurchase from my fork and replay event evt_… that I already verified. Show me which Gmail thread it picked and the draft id. Do not send the draft.

What you see

The homepage card is a tile with the kicker Event and the title Purchase thanks. It links here.

Where to go next

• Subscriptions and events — kody.emits, events.dispatch, filters, synthetic dispatch.
• Inbound webhooks — Stripe signature windows and mint / rotate.
• Gmail drafts without send — lock the package so a later agent cannot send.
• Flake Hunter — the cron sibling on the same homepage row.