Self-play works: matches converge to 146.8 plies (~49 a round) with a 91% deck-
race rate, so the stalling that static opponents induced is gone. Duplicate match
eval scores 0.4968 with a mean lead of exactly 0.0 -- same deals, same coins, both
seats, deal luck cancelling exactly.
Success criterion 1 does not pass. The carry probe is close to flat: expeditions
opened sit at 5.00 whether the policy is 60 points down or 60 points up. Wager use
does move monotonically across all six carry levels, and in the right direction
(behind -> more multipliers), but the spread is 0.31 wagers.
Two diagnoses, one of which was mine and wrong:
- Residual potential shaping was NOT the cause. Annealing it fully to zero left
the probe just as flat.
- terminal_scale is. At carry -60, tanh((margin - 60)/50) is close to linear over
any realistic round margin, and maximising E[tanh] on a linear stretch is just
maximising E[margin] -- there is no reason to gamble. Risk-seeking only appears
where tanh is sharply convex, which needs a smaller scale. Dropping 50 -> 12
widens the wager spread 0.19 -> 0.31, which is the mechanism showing up.
The probe itself is also mis-scaled: at scale 12, tanh(60/12) is 1.0, so +/-60 is
a saturated dead zone with no gradient and the policy has learned nothing there.
The measurable band is |carry| <~ 2 * terminal_scale, and the probe levels have to
be set from the scale rather than fixed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XBQKgvBbxbheiTF1AVy1Sh
coolguyandClaude Opus 4.8
f170fcdcfd