"Will I have my period the week of the wedding?" is a core prediction question the app could not answer. The calendar marked only the next forecast window and stopped browsing one month out, so a textbook-regular user paged forward into blank months. CycleProjection reaches a year. It is a separate type from Prediction, deliberately: a forecast is something the app scores itself on -- the period arrives inside the window or it does not, and PredictionRecord writes down which -- while a projection eleven cycles out is never scored, never learned from, and will have been replaced four times before its date arrives. Separate types mean a projection cannot reach the accuracy figures by accident. Three rules keep it honest, each with a test named after it. Uncertainty grows as sqrt(n), because cycle lengths are near-independent draws: eleven cycles out is about three times as uncertain as one, not eleven times. Real cycles do correlate, so that is the optimistic edge -- which is the second reason the assumption sentence is mandatory. It declines rather than stretching. Past ten days either side a projection stops being an answer, so the projection ends and reports that it ended -- FertilityEstimate's precedent, which already refuses to show a seventeen-day fertile window. The caller can tell "no period due here" from "cannot see this far", and only the second invites her to log more. The assumption is stated, not implied. Any month showing projected marks carries "If your cycles continue as they have, this is the forecast" with the confidence for that distance beside it. A year-ahead date drawn without that is the clearest overstatement this app could make. Cycle 1 is the engine's own forecast copied through unchanged, so the calendar and the Today screen cannot disagree about the next period. The typical cycle length comes from her own history and never a population default -- projecting 29 days for a 35-day user is §3's core defect repeated twelve times over. PROJECTED_PERIOD is its own mark: the same dashed ring as a prediction, thinner and finer. The family resemblance is the message -- still a period, weaker claim -- and it survives greyscale, which an opacity difference would not. Screen readers get the distance in the label, since they cannot see that a square is months away. Browsing now reaches a year; logging still stops at today. ConfidenceRow and readable() move to feature/common and are shared with the Today screen rather than copied. Two of them drifting apart is a screen saying Medium in dots and Low in words. closes #57 Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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| docs | ||
| domain | ||
| gradle | ||
| scripts | ||
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| README.md | ||
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README.md
Privacy: Period Tracker
Status: Draft
Owner: _null
Last reviewed: 2026-08-20
Governs: README.md as the project-facing overview for Privacy: Period Tracker
Review trigger: The first buildable feature release; any change to the stack, the
privacy promise, or how the project is built and run
A private Android period tracker that learns your cycle rather than the average person's — and never sells your data.
What it is | Status | Build and run | Repository map | Project docs | Agent notes
{ Android / Google Play | Kotlin + Jetpack Compose | Room, offline-first | Personalized prediction with an honest window | Discreet notifications | No account, no server, no data sale }
The core loop is:
Track → Learn → Predict → Remind → Learn again
What it is
A focused tracker that answers one question well: when is my next period likely to start? It records confirmed period dates, learns the individual's pattern from them, and produces a most-likely date with a window and a confidence label — never a bare date presented as fact. From that it estimates ovulation and the fertile window, and it asks discreetly whether the period started, using both yes and not yet to improve the next forecast.
Two promises hold the product up:
Your period. Better predicted. — once there is enough personal history, the app must not fall back to a generic 28-day cycle. A user recording 34, 35, 36, 34, 35 who is predicted 28 is a core product defect, not a tuning issue.
Your cycle belongs to you. We will never sell period history, fertility information, ovulation estimates, cycle predictions or personally identifiable information — to advertisers, data brokers or anyone else.
The second is held structurally rather than remembered, and the rule was written
before the code it constrains: checkModuleBoundaries in the root
build.gradle.kts already carries ":core:ads" to emptySet(), so when the ads
module arrives in Batch 07 it may declare no project dependency at all —
stricter than "nothing from the cycle database or the prediction domain". It is
not in settings.gradle.kts yet, so today the rule matches no module, which is
why the guard is proved against injected violations rather than trusted.
What it deliberately is not — no community, no pregnancy mode, no chatbot, no article feed, no symptom encyclopedia, and not contraception — is in docs/planning/PROJECT_PLAN.md.
Status
Foundation through Batch 06 are closed, Batch 08 polish is complete, and monetization (Batch 07) remains unbuilt. Every row below cites the file or test that proves it.
| Surface | Status | Evidence |
|---|---|---|
| Documentation tree and tracker convention | Adopted | this tree; milestones and issues in the tracker |
| Gradle / Kotlin / Compose project | Builds | ./gradlew assembleDebug and assembleRelease both pass |
| Material 3 theme and tokens | Built | core/designsystem |
| Four-tab navigation shell | Built | app/src/main/kotlin/dev/privacyllc/period/navigation/PeriodApp.kt — Today, Calendar, Insights, Settings, each wired to its real screen |
| Cycle model and interval derivation | Built | domain/cycle (13 tests); domain/prediction/src/main/kotlin/dev/privacyllc/period/domain/prediction/IntervalAnalysis.kt (12 tests) |
| Prediction engine | Built — personalized | PersonalPredictionEngine, wired in app/src/main/kotlin/dev/privacyllc/period/di/DataModule.kt; the 12 acceptance tests from PRODUCT_PLAN §51 run against both engines (PersonalAcceptanceTest, BaselineAcceptanceTest), and EngineComparisonTest scores the personal engine against the retained baseline every build |
| Room persistence, DataStore | Built | core/database (schema v1 exported, SchemaTest + scripts/schema-guard.sh), core/datastore, core/data |
| Onboarding, Today, Calendar, Insights | Built | app/src/main/kotlin/dev/privacyllc/period/feature/ — onboarding, today, calendar, insights; OnboardingViewModelTest, TodayViewModelTest, TodayUiStateTest |
| Fertility window and ovulation estimate | Built | domain/prediction/src/main/kotlin/dev/privacyllc/period/domain/prediction/FertilityEstimate.kt, 11 tests; shown on Today and Calendar |
| Discreet notifications | Built | core/notifications (24 JVM tests), instrumented NotificationPrivacyTest |
| App lock (PIN + fingerprint) | Built | core/security (Keystore-backed verifier, lockout policy), app/src/main/kotlin/dev/privacyllc/period/lock gate; 28 JVM tests plus KeystoreVerifierTest run on PeriodMinSdk26 and PeriodQA |
| Discreet launcher alias | Built | app/src/main/AndroidManifest.xml aliases; LauncherAliasSwitcherTest, PrivacyViewModelTest; device checked on emulator-5554 |
| Export My Data | Built | core/export (format pinned byte-for-byte against core/export/src/test/resources/golden-v1.json), written through the Storage Access Framework by app/src/main/kotlin/dev/privacyllc/period/feature/export |
| Monetization | Not built | Batch 07 |
| QA | Round 3 run, partial | docs/qa/ClaudeReport.md — partial at 0451fbe; TalkBack, text scaling, minSdk and a real locked screen still unreached |
BaselinePredictionEngine is still in the tree, but it stopped being the
product in Batch 02. DataModule provides PersonalPredictionEngine — the
recency-weighted, trend-aware, "not yet"-conditioned engine PRODUCT_PLAN §12
specifies — and the baseline is now the control: EngineComparisonTest scores
both over the §51 fixtures every build, so "the new engine is better" is a number
rather than an opinion.
Build and run
Prerequisites: a JDK 21 and the Android SDK with platform 37 and
build-tools 37.0.0 installed, ANDROID_HOME set.
git config core.hooksPath .githooks # per clone, every clone — see below
./gradlew test # JVM suites, no emulator, ~1s
./gradlew assembleDebug # app/build/outputs/apk/debug/
./gradlew assembleRelease # minified, unsigned
compileSdk is 37 because the current AndroidX libraries require it;
targetSdk is 36, Google Play's floor for new apps from 2026-08-31. They are
deliberately different — raising targetSdk opts the app into runtime behaviour
changes and is a tested decision, not a build fix.
git config core.hooksPath .githooks is per clone. Without it the hooks are
not installed and fail silently, which is the failure mode they exist to
prevent. post-commit pushes; see
docs/architecture/githooks/README.md.
Repository map
app/ application module, MainActivity, navigation shell, DI
core/designsystem/ Material 3 theme and colour tokens
core/database/ Room entities, DAOs, converters, the exported schema
core/datastore/ user preferences that are not health history
core/data/ CycleRepository — the only module that touches a DAO
core/notifications/ reminder copy, privacy modes, WorkManager scheduling
domain/cycle/ pure Kotlin — period records, cycle derivation
domain/prediction/ pure Kotlin — the forecast, window and confidence
scripts/ six from the template, plus schema-guard.sh, our own
.githooks/ pre-commit, commit-msg, post-commit
docs/ product, architecture, design, brand, QA, security, history
domain/* are kotlin("jvm") modules and cannot see the Android SDK. That is
on purpose: the prediction engine is the product, so it needs the most tests,
and tests that need an emulator are tests that do not get run.
Project docs
Detailed procedures belong in docs; open work belongs in the tracker, not in this README.
| Doc | Purpose |
|---|---|
| docs/DOC_TRUST_MAP.md | Which document owns which answer, and which source wins when records disagree. Read this first. |
| docs/planning/PRODUCT_PLAN.md | The full V1 specification — prediction requirements, screens, copy, compliance |
| docs/planning/PROJECT_PLAN.md | The short vision, the stack and its reasons, and what this is deliberately not |
| docs/WORK_CYCLE.md | What happens at the end of a piece of work |
| docs/architecture/README.md | Modules, boundaries, data shapes, migrations |
| docs/design/README.md | Tone, and the four rules that settle design arguments |
| docs/security/SECURITY.md | Threat model, the advertising boundary, logging rules |
| docs/TOOLS.md | Which script to run, and which ones can stop you |
Where the tracker is
Milestones are batches, issues are deliverables, and severity labels are exactly
P0, P1, P2 and release-blocker. Credentials come from the environment,
never from this repository:
set -a; . ~/.openclaw/docker-registry.env; set +a
python3 scripts/forgejo-issue.py list
Two traps that cost an hour each otherwise: Cloudflare 1010-blocks clients that
do not look like a browser or curl, so every request needs
User-Agent: curl/8.5.0 — forgejo-issue.py sends it and anything new must
too. And /issues returns pull requests unless type=issues is passed.
Agent notes
- Product truth comes from the code and the tracker before prose.
- Do not keep a work list in this README or anywhere else in
docs/. - Finish with docs/WORK_CYCLE.md, every time: close what you finished with the evidence, close the milestone if the batch landed, update the documents the change triggered in the same commit, push, log the entry, then reconcile and write the summary and next action.
- Nothing on privacyllc.dev writes itself except the tracker counts and the pushed docs.
- Do not claim a feature is built unless you can cite the file, test or screenshot that proves it. The status table above is the standard.
- Verify current stable versions before changing the toolchain. The ones in
gradle/libs.versions.tomlwere checked against the official sources on 2026-08-18; PRODUCT_PLAN.md asks for that check rather than for its own numbers to be trusted. - Never put a cycle date, a prediction or a fertility state into a log, an analytics event, or an ad request.