DayOtter's optional client analytics module (Mixpanel + Google Analytics 4 + PostHog) in apps/web/lib/analytics.ts. Two independent switches - per-provider env config (deployer) and a per-browser opt-out (end user). Load this when adding tracking, wiring a new provider, or changing consent behavior.
How scheduling actually works in DayOtter - the pure availability engine (DST-correct, integer-ms slot math), the busy_blocks cache the sync worker maintains, provider adapters, best-effort push subscriptions, and the booking lifecycle fan-out. Load this when touching availability, calendar sync, busy caching, bookings, or the sync/reminder workers.
Orientation for the DayOtter monorepo - layout, the single sources of truth (availability engine, sync worker), the load-bearing invariants (timezone discipline, confirm-first AI, encryption, SSRF-safe egress, single runtime), and how to build/test/verify. Load this first when starting work anywhere in the repo.
How DayOtter's self-hosted vs cloud editions work, gated by the DAYOTTER_CLOUD deploy flag and lib/billing/edition.ts. Load this when touching billing, CRM, messaging, managed AI, the ee/ layer, or any feature that should behave differently on the hosted product - or when a "self-hosted / not configured" message shows up where cloud behavior was expected.
apps/web UI conventions - theme tokens and class-based dark mode, the marketing/docs/blog width tiers, brand typography (Geist, no serif), illustration gotchas (baked light frames cause dark-mode edges), reveal animations, and the Card system. Load this when doing marketing or app UI work so new pages match the rest of the site.
DayOtter's plugin/extension system - in-process, config-listed plugins that extend the product without forking (notes, scribing, custom integrations, booking hooks). Covers the plugin-sdk/plugin-host packages, plugin_data storage, the host context (safeHttp via safeFetch), and the trust model. Load this when adding an extension point, writing a plugin, or touching the plugin host.