The baseline-drift card reported a pulse in the hundreds of millions against a
usual range in the tens of thousands. Neither figure is a heart rate, and both
came from the same place.
The application declares a plausibility domain per metric, and every
interactive, import, MCP and Telegram write validates against it. The
derivation layer did not ask. So a single stored value outside that domain — a
provider unit-decode slip, or a row from a writer that never had the gate — was
folded into the day mean, carried by the median into the band, and then held
against itself as "currently". The two numbers in the sentence were wrong by
different amounts, which is why the line read as nonsense rather than as an
exaggeration.
Both readers now refuse a value the application has already declared
impossible: the per-day means behind the band, and the latest-day mean the
deviation reads. A day left with no plausible reading contributes nothing
rather than a fabricated point, and the vital drops out of the comparison — the
coverage floor already knows how to report an absent day. The rollup branch
applies the same rule to a bucket mean, since the rollup writer averages
whatever is stored. Everything downstream of `readDayMeanSeries` inherits it,
which is every consumer of the usual range: the band strip, the drift card, the
changepoint detector, readiness, trajectory, the coach read.
The card also printed raw doubles. Each figure now renders at the metric's own
decimal precision through the shared formatter, so a mean reads as a number
rather than as a float and follows the reader's number convention.
Left open, and recorded for a separate pass: the provider sync writers do not
enforce the domain on the way in, so the impossible rows keep landing.
Marc-André Bombeck
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