[ryanbr]

A user asked why the coach said it couldn't access their sleep stage data. It was telling the
truth.

What the coach could see

parts.append("rest " + (d.totalSleepMin.map { String(format: "%.1fh", $0 / 60) } ?? "—"))

rest 7.5h was every word the context carried about a night. No deep, no REM, no light, no
efficiency. The model wasn't refusing or inventing a limitation — it genuinely had none of it.

The data was never missing

deepMin, remMin, lightMin and efficiency sit on the same DailyMetric row the day line
already reads for totalSleepMin, avgHrv and restingHr. Nothing new is plumbed; they were simply
never included.

That looks like an oversight rather than a decision — #124 widened this same context once before, for
the same reason ("the coach used to see only recovery/strain/sleep/HRV/RHR").

Both platforms, since AiCoach.kt is a twin of AICoach.swift and had the identical gap.

Design notes

Always emitted, dash when absent, exactly like every other field on the line. The alternative —
appending stages only when present — gives the model a schema that changes shape between days and
invites it to read a missing field as a zero. That is the one misreading worth designing against,
because the users most likely to ask about stages are the ones whose strap banks none.

Both system prompts updated too. Each enumerates what the coach may be given, so adding the data
without the prompt would have left the model explicitly told it doesn't have what it just received.
The Swift prompt also now says a dash means NOT MEASURED rather than zero; the Kotlin context header
already said so.

One test repinned, not weakened

sparseRawOnlyDaysRenderDashesNotInventedNumbers asserts one contiguous daily line where every
unrecorded value is a dash. That string now carries the new fields. Contiguous is the point — it's
what catches a field silently dropping out of the line.

Verification

• 14 AiCoach tests, 0 failures, including two new ones: stages reach the context, and an unstaged
  night reports dashes rather than going quiet.
• compileFullDebugKotlin, swiftc -parse, doc_comment_lint, i18n_audit --ci all clean.
• The Swift half is app-target with no local build — the testing build's iOS leg compiles it.

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