Discord bot on Fly.io: invite reconciliation + auto-role

[quinn-dougherty]

Description

Persistent-WS bot that reconciles Stripe-issued single-use invites with joining users and assigns `@attendee`. PLAYBOOK.md §5.2–§5.4.

Why Fly.io (not Vercel)

• Discord gateway needs a long-running WebSocket; Vercel Functions are request-scoped.
• Fallback (interactions HTTP on Vercel) loses `GUILD_MEMBER_ADD` events. Reject.

Responsibilities

• Watch `GUILD_MEMBER_ADD`; diff invite `uses` counts to identify which invite code a joiner used; match to `registrants` row; assign `@attendee`.
• `/whois ` slash command for organizer lookup.
• Cron-post schedule reminders to `#announcements`.
• Auto-kick unregistered joiners after 10 min grace.

Invite issuance (called from Stripe webhook)

• On `checkout.session.completed`: server calls Discord REST `POST /channels/{lobby}/invites` with `max_uses:1, max_age:0, unique:true`.
• Store code on `registrants.discord_invite_code`.
• Email registrant their personal link.

Failure modes to handle

• Registrant never joins → invite stays valid; T-7 reminder email.
• User joins on different account than email on file → surface in `/admin` for manual reconciliation.

Env vars

• `DISCORD_BOT_TOKEN`, `DISCORD_GUILD_ID`, `DISCORD_LOBBY_CHANNEL_ID`, `DISCORD_ATTENDEE_ROLE_ID`.

Monitoring

• Sentry project for the bot (separate from Vercel Observability on the web app).

Dependencies

• Discord server + IDs (Spin up Discord server + channels/roles + runbook #5).
• Stripe webhook (Build /register + Stripe Checkout + webhook #4).