Companion

The field-tested reference curve (Riyaz's long-shipped tanh, preserved exactly for score-history continuity).

Raw scores pass through unchanged. The default.

Generous low-and-mid boost: rough takes get visible credit.

Closer to raw: the middle is not flattered.

A client-supplied curve. Must be monotonic non-decreasing over 0..1 and finite everywhere; outputs are clamped to 0..1 at apply time.