Decisions (v0)

The PRD ("Newborn Log — PRD") plus the changes agreed while planning, and the calls made during the overnight build. Each entry says why.

Product

Topic	Decision	Why
Name	Wee Hours (com.hejitech.weehours)	Built for the wee hours with a wee one. Short, warm, not clinical
App Store name	Wee Hours: Hands-Free Baby Log (30 chars, the limit); the home screen stays "Wee Hours"	The name drives search; "hands-free" is what sets it apart. The subtitle can carry "baby tracker" or "voice"
Platform	Native iOS + watchOS first; Android later	Siri, Action Button, widgets and Live Activities are what let the phone stand on its own
Tracking	A type registry; every category is optional (bottle, breast, pumping, solids, diaper, sleep, growth: weight, height, head size)	Support every family; fewer enabled options also make the model more accurate
Advice	The app records facts; MCP exposes them; the user's own agent interprets	No medical advice from us; no aggregation in the app beyond the status line
Pediatrician PDF	Dropped; raw CSV export instead	Aggregation is the agent's job
Billing	Monthly / yearly subscription and a lifetime purchase, per household, 14-day trial	As requested. Judgment call: tap logging stays free after the trial so parents never lose access to their own log

Architecture

Topic	Decision	Why
Decision model	One unified model: Laya (0.4B ModernBERT, Q8 GGUF) via llama.cpp, on-device	Your choice. llama.cpp has decision models only in llama-server, so the decision path is ported to Swift (ios/LayaRuntime), with parity tested against the server
Question design	Event type = category × phase, not one 13-way question	Zero-shot Laya: 81% vs 13% type accuracy, and 0% vs 89% wrong auto-commits (eval/results)
Time and numbers	Clock times, relative times, ml/oz, kg/lb are parsed deterministically	The PRD already did this for clock times; Laya scored 21% on the "when" question
Calibration	Per-question temperature on top of Laya's own, fitted by logeval --fit	Thresholds only mean something if probabilities are calibrated
Sync	Supabase (Postgres + RLS), append-only events, an outbox plus a seq cursor	Android later; MCP needs server-side reads
Glasses voice	The glasses upload audio as a capture; a household phone processes it on open or on background refresh. Event id = f(capture id)	No server inference cost; all processing stays on the phone; two phones converge
Glasses gestures	Typed events go straight to Supabase (offline outbox); hold-to-speak attaches to the entry you just made	Time-critical facts (last feed) never wait for voice processing
Auth	Supabase Auth (Google, Apple, email for dev), shared by the app and MCP OAuth; personal access tokens for other agents	One identity everywhere
Local-only mode	"Use without an account" keeps the household on the phone (no Supabase); signing in later re-homes the never-synced rows and uploads them	The phone must stand alone; nothing is lost when moving to an account
Consistency	spec/ is the single source; Swift and TypeScript run the same derivation fixtures	Prevents status drift between the phone, glasses and MCP

Monorepo (2026-10-15)

Topic	Decision	Why
Home	Wee Hours moved into the HEJI monorepo (tianhaoz95/hejitech-apps, projects/weehours) with its history; the old repo is archived	Share one Supabase project (one plan's quota) and CI plumbing across the HEJI apps; easier to build an ecosystem
Database	Its own Postgres schema weehours and bucket weehours in the shared project, not public	Waypack predates the convention and owns public (it has its own entitlements table); accounts are shared, data isn't
MCP OAuth	The site's Cloudflare Worker is the OAuth server (@cloudflare/workers-oauth-provider, like Waypack); the MCP server moved from a Supabase Edge Function into that Worker	Owner's choice (a). Supabase's OAuth server has one consent URL per project, relative to the Site URL, which Waypack owns. A neutral shared consent router stays an option for later projects
Sign-up rows	Waypack's on_auth_user_created trigger is dropped; each app creates its rows on first use	Owner direction: one user pool for every app
Signing	TestFlight CI uses the team-wide HEJI identities Waypack uses (same certificates)	Owner direction; one set of secrets, never minting certificates
Google sign-in	The shared project's Google provider (HEJI web client) through Supabase in the system browser sheet with PKCE, returning to weehours://login-callback; the site uses the same provider	Owner request (2026-10-16). Reuses what Waypack set up, so no iOS OAuth client or GoogleSignIn SDK; Google shows the shared HEJI branding
Build numbers	Stay UTC timestamps	Builds already uploaded use them; Waypack's 2000 + run number would go backwards

Several children (2026-10-17)

Topic	Decision	Why
Now screen	Direction 03 "Log-for bar" from reports/weehours-multi-child: every shown child's status side by side, a sticky "Log for" bar over the buttons (any number of children, plus Both/All), foldable to one line; with one shown child, no bar and no extra card	Owner's pick, with: arbitrary child count, no wasted space for one child, fold for long stretches with one child
Which children a phone shows	Per phone (Settings → Children → Show on this iPhone); archiving is household-wide	Owner request: a family with three children can keep two on this phone
Per child	Name, birth date, colour, bottle size and quick-feed override; categories, reminders' intervals, caregivers, night window and duty stay household-wide	Recommended in the proposal; nothing else asked for
Several at once	One event per child sharing a group field; Undo takes them back together	Each child keeps a clean log; MCP and CSV need no new concept
Voice	Names in the sentence win ("the twins", "both of them" = all); otherwise the device's current child	Names are parsed deterministically, so the model's questions don't change
Price	Unchanged: one purchase covers every child	Recommended; families with twins shouldn't pay twice

Not done yet

See the report (report/v0/site, "What's verified") for what was verified in simulators and what still needs devices or the hosted project.