# AGENTS.md — Build guide for Systeme.io

## Project scope
Publish a small funnel, collect consented signups and sell access to one course through Stripe Checkout. Deliver lessons through authenticated entitlements and run a simple reviewed email sequence.

Catalogue verdict: kinda. None of the individual pieces here are hard: a landing page, an opt-in form, a contacts table, a Stripe checkout, a gated video page, a ref-code cookie. An agent can wire all of that into one self-hosted app in a weekend and you will own the list outright. What you cannot one-shot is the boring operational layer: domain authentication, bounce and complaint handling, unsubscribe compliance, and the fact that sending 20,000 emails from your own setup means you now care about deliverability as a personal hobby. You also lose the drag-and-drop editor, which sounds cosmetic until you want to change a headline at 11pm without opening an editor. Verdict lands at kinda because the value survives the rebuild but the maintenance does not disappear.
Use the implementation prompt below to define the deliverable. Complete each phase's acceptance checks before extending the scope.

## Working agreement
- Inspect the repository and its existing instructions before choosing paths, dependencies or commands. Keep one coherent stack and explain changes to the proposed architecture.
- Plan a vertical slice that accepts a real input and produces the useful output described below. Persist only the state the prompt calls for; respect memory-only and upstream-managed workflows. Use fixtures only when they are clearly labelled.
- After scaffolding, document the actual install, development, check and build commands in README and keep them synchronized with the package or project manifest. Do not report commands as successful unless they ran.
- Work in small steps. At handoff, list implemented flows, checks actually performed, remaining blockers, and any credentials or provider setup the owner must supply.
- Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization.

## Prerequisites
- A supported Node release, PostgreSQL, HTTPS for a shared deployment, and a backup destination. Begin with one workspace and explicit owner/member permissions. Stripe integration requires the account keys, verified webhook secret and public HTTPS endpoint; start with sandbox fixtures before live payments.
- Implementation components: Next.js App Router and TypeScript for server-rendered pages and validated mutations. PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace.
- Scope boundary: Automated affiliate payouts, tax calculation and broad commerce integrations are deferred.

## Stack and architecture
- Next.js App Router and TypeScript for server-rendered pages and validated mutations.
- PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace.
- Domain model: funnel pages, consented opt-ins, products, checkout sessions, course entitlements, drip steps and referral records

## Security and data integrity
- Authorize every record read and mutation on the server using its workspace membership; validate payloads, protect mutations against CSRF, and escape user-authored HTML.
- Correctness boundary: A referral records attribution but never proves a payment; access and affiliate accounting follow verified payment/refund events and immutable order snapshots.
- Commit related database changes in one transaction. Use version checks for competing edits and an outbox for external notifications; retry delivery independently of saving the record.
- Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching.

## Agent implementation rules
- Project rule — data model: funnel pages, consented opt-ins, products, checkout sessions, course entitlements, drip steps and referral records
- Project rule — preserve this invariant: A referral records attribution but never proves a payment; access and affiliate accounting follow verified payment/refund events and immutable order snapshots.
- Project rule — acceptance evidence: Replay a purchase webhook and grant one entitlement; an unsubscribed buyer keeps purchased access while marketing drip messages stop.

## Optional agent skills and references
- Optional external skill: [vercel-react-best-practices](https://github.com/vercel-labs/agent-skills/blob/main/skills/react-best-practices/SKILL.md) — Improve React and Next.js data fetching, rendering, bundle size and server performance. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
- Optional external skill: [supabase-postgres-best-practices](https://github.com/supabase/agent-skills/blob/main/skills/supabase-postgres-best-practices/SKILL.md) — Review PostgreSQL schemas, queries, indexes, pooling, concurrency and row-level security. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
- Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
- Optional external skill: [stripe-best-practices](https://github.com/stripe/ai/blob/main/skills/stripe-best-practices/SKILL.md) — Plan Stripe checkout, subscriptions, webhooks, platform payments and secure API integration. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.

Read the linked SKILL.md and its dependencies before adding a skill. Select only the skills matching this project's runtime and task; their documentation does not supply API access, credentials or approval to perform external actions. Pin the reviewed revision where the tool supports it. Follow the chosen agent's documented project-level installation mechanism.

## Distribution ideas
These are optional planning notes. Obtain the owner's approval before publishing or contacting anyone.
- Demonstrate the actual Systeme.io-inspired workflow with owned or clearly labeled sample data: Publish a small funnel, collect consented signups and sell access to one course through Stripe Checkout. Deliver lessons through authenticated entitlements and run a simple reviewed email sequence.
- Publish a reproducible walkthrough with this observable result: Replay a purchase webhook and grant one entitlement; an unsubscribed buyer keeps purchased access while marketing drip messages stop.
- Explain who can operate this scoped tool, its setup and ongoing costs, and these remaining product gaps: Automated affiliate payouts, tax calculation and broad commerce integrations are deferred. Avoid guaranteed savings, performance scores or implied endorsement.

## Engineering roadmap
1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Publish a small funnel, collect consented signups and sell access to one course through Stripe Checkout. Deliver lessons through authenticated entitlements and run a simple reviewed email sequence. Record prerequisites, select representative user-owned fixtures and document the unsupported features: Automated affiliate payouts, tax calculation and broad commerce integrations are deferred.
2. Phase 2 — Durable model. Model funnel pages, consented opt-ins, products, checkout sessions, course entitlements, drip steps and referral records Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: A referral records attribution but never proves a payment; access and affiliate accounting follow verified payment/refund events and immutable order snapshots.
3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Commit related database changes in one transaction. Use version checks for competing edits and an outbox for external notifications; retry delivery independently of saving the record.
4. Phase 4 — Permissions and integration failure. Authorize every record read and mutation on the server using its workspace membership; validate payloads, protect mutations against CSRF, and escape user-authored HTML. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
5. Phase 5 — Portable handoff. Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
6. Phase 6 — Acceptance scenarios. Replay a purchase webhook and grant one entitlement; an unsubscribed buyer keeps purchased access while marketing drip messages stop. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.

## Paid-product capabilities outside this build
- Visual page and email editors, plus the template library that makes launching a funnel a copy-paste job
- Managed deliverability: shared sending reputation, bounce suppression, spam complaint handling
- Affiliate program plumbing at the level people expect, including payouts and dashboards for your affiliates
- Webinars, blogs, and the odd extras that come free in the bundle
- One vendor to blame when checkout breaks on launch day

## Implementation prompt
WORKING SLICE
Publish a small funnel, collect consented signups and sell access to one course through Stripe Checkout. Deliver lessons through authenticated entitlements and run a simple reviewed email sequence.

Build this scoped Systeme.io-inspired workflow with a documented data model and visible failure states.

Architecture
- Next.js App Router and TypeScript for server-rendered pages and validated mutations.
- PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace.

Prerequisites and limits
A supported Node release, PostgreSQL, HTTPS for a shared deployment, and a backup destination. Begin with one workspace and explicit owner/member permissions. Stripe integration requires the account keys, verified webhook secret and public HTTPS endpoint; start with sandbox fixtures before live payments.
Outside this release: Automated affiliate payouts, tax calculation and broad commerce integrations are deferred.

Data model and correctness
funnel pages, consented opt-ins, products, checkout sessions, course entitlements, drip steps and referral records
Invariant: A referral records attribution but never proves a payment; access and affiliate accounting follow verified payment/refund events and immutable order snapshots.
Commit related database changes in one transaction. Use version checks for competing edits and an outbox for external notifications; retry delivery independently of saving the record.

Security and privacy
Authorize every record read and mutation on the server using its workspace membership; validate payloads, protect mutations against CSRF, and escape user-authored HTML.

Recovery and export
Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching.

Implementation order
1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Publish a small funnel, collect consented signups and sell access to one course through Stripe Checkout. Deliver lessons through authenticated entitlements and run a simple reviewed email sequence. Record prerequisites, select representative user-owned fixtures and document the unsupported features: Automated affiliate payouts, tax calculation and broad commerce integrations are deferred.
2. Phase 2 — Durable model. Model funnel pages, consented opt-ins, products, checkout sessions, course entitlements, drip steps and referral records Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: A referral records attribution but never proves a payment; access and affiliate accounting follow verified payment/refund events and immutable order snapshots.
3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Commit related database changes in one transaction. Use version checks for competing edits and an outbox for external notifications; retry delivery independently of saving the record.
4. Phase 4 — Permissions and integration failure. Authorize every record read and mutation on the server using its workspace membership; validate payloads, protect mutations against CSRF, and escape user-authored HTML. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
5. Phase 5 — Portable handoff. Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
6. Phase 6 — Acceptance scenarios. Replay a purchase webhook and grant one entitlement; an unsubscribed buyer keeps purchased access while marketing drip messages stop. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.

Acceptance
Replay a purchase webhook and grant one entitlement; an unsubscribed buyer keeps purchased access while marketing drip messages stop.
Use real source data or clearly labeled fixtures. Explain unsupported input and provider failures; do not fabricate analytics, delivery receipts, accuracy claims or security guarantees.

Optional agent guidance
Optional external skill: [vercel-react-best-practices](https://github.com/vercel-labs/agent-skills/blob/main/skills/react-best-practices/SKILL.md) — Improve React and Next.js data fetching, rendering, bundle size and server performance. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [supabase-postgres-best-practices](https://github.com/supabase/agent-skills/blob/main/skills/supabase-postgres-best-practices/SKILL.md) — Review PostgreSQL schemas, queries, indexes, pooling, concurrency and row-level security. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [stripe-best-practices](https://github.com/stripe/ai/blob/main/skills/stripe-best-practices/SKILL.md) — Plan Stripe checkout, subscriptions, webhooks, platform payments and secure API integration. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Project rule — data model: funnel pages, consented opt-ins, products, checkout sessions, course entitlements, drip steps and referral records
Project rule — preserve this invariant: A referral records attribution but never proves a payment; access and affiliate accounting follow verified payment/refund events and immutable order snapshots.
Project rule — acceptance evidence: Replay a purchase webhook and grant one entitlement; an unsubscribed buyer keeps purchased access while marketing drip messages stop.

## Completion evidence
Demonstrate the prompt's acceptance scenarios against the scoped workflow. Include setup from a clean checkout and failure recovery. Check persistence across restart and export/restore only for the state the prompt says to store; for memory-only tools, confirm that temporary content is discarded as specified. Record actual results and remaining limitations. A detailed plan alone does not establish a working replacement.