CB-RES-0008 with a runnable baseline
(games/ground/examples/difficulty-baseline.rs), and the measurement
produced a finding before any solver exists.
A GREEDY BOT WINS 200 OF 200 GAMES AT FIVE AND SIX SEATS. Median margin
+3, 11.8-12.0 points available against a threshold of 9. The curve is
66% / 82.5% / 95% / 100% / 100% across 2/3/4/5/6 seats.
Row-level, as GROUND-WP-0004 T02 requires: available points 6 / 9 / 12
against thresholds 5 / 7 / 9, so the ratio RISES with seat count (1.20,
1.29, 1.33) while the table also gains actions per round to clear it with.
Three multipliers pointing the same direction.
It also explains the maintainer's report without needing a solver at all:
"I felt it was too easy but then we lost" is two true statements about
different seat counts.
Cost measured and it rules out the obvious approach. Branching is small
(mean 4.7-9.1) but legal_commands costs 112-161 us per call because it
filters candidates through full validate. Exhaustive search is out at
every seat count; 10^4-10^5 nodes is 1.4-14 seconds, which is the budget
the ADR must design inside.
Prior art names the trap: determinized search (PIMC) suffers strategy
fusion (Frank, Basin & Matsubara 1998) -- the search picks different
actions in states a real player cannot distinguish, so the witness may
require knowing what was on top of the deck. Such a line still replays
green, so the checkability benchmark does not catch it. Honesty and
checkability are different properties; stated explicitly so T03 cannot
conflate them.
The survey states its own most likely killer up front (§6): a view-only
search cannot fold events, so making the information boundary structural
rather than a promise may not be affordable. Better found here than in
T05.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Five remarks from the maintainer's test games, checked against the code
before being written down — two had already reached ground-game on wrong
premises, so a claim now names the line that makes it true.
Three of the five turned out to be data the projection already carries,
drawn as text: solution_deck_len, solution_discard, and OutcomeView's
personal/mastery/winners. One control (`close — I have read this`) is
labelled as a reading but shuts the server down, and leaves a live-looking
page pointing at a dead port. One number does not exist at all: table.rs
loops run_game and keeps only the last summary.
CB-WP-0024 (S, chaos d8=6, declaration 7 of window 2) — the piles and the
other seats' plays as objects on the table, the ending control saying what
it does, and a tally that survives "play again".
CB-WP-0025 (L, chaos d8=6, declaration 8) — "could we have won" and "how
hard is this" are the same search asked twice. Tier L because the
information boundary is the whole design problem: a solver reading
GroundState sees the deck the rules hide, and would tell the maintainer he
could have won by playing a card he had no way to know was there. Also
unblocks GROUND-WP-0005, active with both tasks waiting on a measured
difficulty baseline.
Also: CB-WP-0022 T07's evidence file moves to CB-EV-0021 — CB-WP-0023
shipped CB-EV-0020 first.
loop-lint: no findings.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
