Fortuity Sleep capabilities

Last updated Sunday, October 4, 2026. Every capability below is in the current build for iPhone, iPad and Apple Watch, with the mechanism that produces it.

Platforms

iPhone and iPad on iOS and iPadOS 26 (universal app). Apple Watch on watchOS 26 (companion app).
Price: $24.99, paid once, with no subscription. While it installs through Apple's TestFlight, it is free.
Data source: Apple Health sleep analysis written by Apple Watch, plus heart rate, heart rate variability, respiratory rate, blood oxygen, wrist temperature and Apple's breathing disturbances measurement. Read-only: the app asks for no write access.

Reading last night

Capability	Mechanism	How to verify
Night selection by session clustering	Samples are grouped into sessions on gaps longer than 90 minutes; last night is the most recent session of 3 hours or more that ended within the last day. Shorter sessions are naps.	Take a 40-minute afternoon nap: it appears under Naps and last night's total is unchanged.
One recorder per night	When several sources wrote the same session to Apple Health, the source with the most staged sleep is used, then the most asleep time. The others are set aside and named in a footnote.	Run another sleep app that writes to Apple Health alongside the watch: last night's total matches the watch alone.
"Not recorded" instead of zero	Per-stage totals are shown only when at least 50% of asleep time carries a stage. Otherwise deep, REM and core read "not recorded". On a staged night, an absent stage is a measured zero and reads 0m.	A night recorded without Sleep Focus shows "not recorded" for deep and REM.
Efficiency and wakings	Efficiency is asleep time divided by time from sleep onset to final waking. A waking is an awake stretch of 5 minutes or more after onset.	Shown on the Last night card.
Hypnogram	Awake, REM, Core and Deep each on their own row across the night, drawn from the session's samples.	Tonight screen, "The shape of the night".

Verdicts and the morning sentence

Verdict	Fires when	Action for tonight
Short night	Asleep 45 minutes or more under your own median	Be asleep earlier by the shortfall
Long night	Asleep 45 minutes or more over your median	None
Late bedtime	Sleep onset more than 1 hour after your circular median onset	Wind down at your usual hour
Broken night	3 or more wakings of 5 minutes or more	Dark, cool room; no alcohol within 3 hours of bed
Low deep sleep	Deep under 10% of asleep time, staged nights only	Earlier bedtime
Breathing elevated	Apple's own breathing disturbances classification reads elevated	If it repeats, show your doctor
Stages missing or partial	No stage data, or under 50% staged	None needed
Steady	Nothing else fires	None

Ranking: a data-quality verdict always outranks good news, so a night that could not be read is never headlined by a cheerful card.
The sentence: Apple's on-device Foundation Models session receives the finished verdict, its action and its evidence, with a 2,048-token budget, and returns one sentence. A sentence containing a number absent from the evidence, a diagnosis word, an exclamation mark, or over 280 characters is discarded and the rule's own sentence is shown. Timeout: 6 seconds.
Personal norm: median asleep time and circular median bedtime over your last 30 nights, built from nights before last night, and only once 7 nights of 3 hours or more exist.

Trends

Time asleep per night for 14 or 30 nights, with your norm drawn across and nights 45 minutes or more under it marked.
Bedtime consistency: sleep onset per night on a noon-to-noon clock, and the spread between earliest and latest.
Averages: mean asleep time, bedtime spread, mean efficiency.

Apple Watch

Reads Apple Health on the watch itself and runs the same engine as the iPhone: hours asleep with the sleep window, the headline verdict, tonight's action, deep, REM and core tiles (or "n/r" when not recorded), and the difference from your norm.

Engine

FortuitySleepKit, a Swift package with no HealthKit dependency, so every rule is a pure function tested off-device: 61 tests, including a decoy night recorded twice that must count once.
The same engine powers the Sleep mode in Fortuity Health.