chat2/02 dissolved the terraces and lost two thirds of the mountain with them, then
concluded the loss was structural and needed a Phase-1 noise change. That conclusion
was wrong, and this commit is the refutation.
A monotone curve is a free reparametrization: it may be gentle in one place and steep
in another, and can lift bottom-heavy input into a substantial massif without ever
going flat. The area above a height is set by where the percentile->height mapping
crosses it, and that mapping is entirely ours to choose. The 02 sweep that "proved"
the loss structural varied climbFeather, which shapes the JOIN, not the mass
distribution — the wrong knob, and too strong a conclusion drawn from it.
Core/ClimbCalibration — the climb's control points are now MEASURED off the staircase
instead of invented from shape knobs. For p in {10,30,50,70,85,95} of above-ceiling
land, take that percentile's raw height and its staircase output height; PCHIP through
the pairs. That reproduces the staircase's elevation envelope, so the mountain mass
returns, while MinNormalizedSecant floors every grade so the flat bench and plateau
interiors become slope. The floor bites on exactly one segment — the plateau — which
is precisely where the staircase was flat.
ContinuousCurve.BuildCalibrated joins it to the same pinned lowland handover, the same
C1 join and the same per-seed spikeMax. The 02 analytic path survives unchanged as the
"before" contrast, and deliberately keeps its strictly-increasing-secant rule: a
calibrated curve is WAVY by design, so convexity is the wrong invariant for it and the
secant floor is the right one.
peakSharpness replaces summitDrama and fixes its bad trade. Drama steepened the peak by
pulling the summit ONSET down, dragging the whole massif with it (p99 199 -> 121 m).
Sharpness reshapes only above the last measured percentile, leaving that height fixed,
so peak and massif are independent: raising it leaves p90, >100 m and >220 m untouched
and only moves land within the summit.
Measured, both seeds, 2048:
variant >100 m >220 m p90
staircase (target) 16.05% 4.53% 127.4 m
continuous_02default 4.80% 0.63% 58.4 m
continuous_restored 14.25% 3.45% 123.2 m
continuous_bigger 19.70% 5.80% 163.5 m
Oracle all hard checks pass, including (a2) staircase still bit-identical to task 01's
dump and (d) lowlands bit-identical across every calibrated variant. New (g) reports
land above 100/220 m per variant and is deliberately NOT gated — it is a taste target
the developer tunes, and gating it would make mountainLift unusable. What it must never
do is stay silent, which is how 02 lost the mountain unnoticed.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DCWNaDZPfTiAy3meGNGgqt
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