clay-borg/decisions
tegwick 3a026b1e1f CB-WP-0025 T03: ADR-0013 -- one world after the game, and difficulty that
does not measure the bot

Seven decisions. Two are not what T03 expected, because the review moved
the ground under both.

D1: strategy fusion DOES NOT APPLY, and that is why the affordable option
is also the honest one. Fusion is a defect of aggregating over
determinizations to choose a move -- the search picking different actions
in states a player cannot distinguish. After the game there is ONE WORLD:
the deal is known, so a search over it yields a line executable in the
only world there is. The survey treated fusion as this pass's central
obstacle; it is an obstacle to a playing engine, which we are not
building. The tool answers "given the deal as it actually was, was there a
line that reached the threshold" and is labelled that way on screen --
never "how you should have played".

D4: difficulty is the WINNABLE FRACTION, not a bot's win rate. C4 killed
the bot rate -- two trivial policies span 0-100% on the same deals, and
improving the bot would make the game "easier" without a rule changing. A
measure that moves when the measurer improves is not measuring the thing.
The solver supplies the alternative: over N deals, in what proportion does
a winning line exist. That is a property of the deal distribution and the
threshold, which is what ground-game tunes and what GROUND-WP-0005 is
blocked on. Ships as a table -- winnable fraction, named reference policy,
skill gap -- never one number, with policy/N/seed-range/K in the number's
name. Stated as a LOWER BOUND, since a K-round search cannot see a line
that needed round 1.

D2: search GroundState. The survey's view-only structural boundary is not
implementable -- a view cannot fold events, and it said so in §6. The
guarantee moves to something checkable: every move in a witness is marked
visible or hidden, computed from project(). A witness reads "you could
have won, but two of these six moves needed a card you had no way to know
was coming" -- more useful than either extreme.

D3: bounded exhaustive over the last K rounds, table as one co-operative
agent, K=2 default. Affordable once C6 corrected the premise: joint
branching over the last two rounds is ~5x10^2 / 1.6x10^5 / 5.7x10^5 at
2/3/4 seats. Wording is normative: "no winning line found in the last K
rounds", never "unwinnable". PIMC and ISMCTS rejected -- they add strategy
fusion to a problem that does not have it.

D5: the harness becomes an instrument before any figure is quoted (C3) --
positive controls, --self-test in make self-tests, a make target, and a
PLURAL policy panel, because the spread between policies is what C4
exposed and hiding it would restore the error.

D6: no new crate and no port. The L declaration was an over-declaration
and is recorded as one. D7: the node cost is disputed 5x between author
and reviewer; T04 benchmarks it with criterion and neither existing figure
may be cited, including by this ADR.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-05 18:47:07 +02:00
..
ADR-0002-game-kernel.md T04: adversarial review round + survey corrections + ADR-0002 (reimplement, assimilate patterns) 2026-07-31 01:25:02 +02:00
ADR-0003-cost-accounting.md T02: ADR-0003 — transcript as instrument, commit intervals as attribution 2026-07-31 08:44:27 +02:00
ADR-0004-am4-ratification.md CB-WP-0019 T01/T02: AM-4b asks what a contributor acquires 2026-08-03 19:04:54 +02:00
ADR-0005-assertion-coverage-and-replay.md ADR-0005 + CB-WP-0005: count assertions, not names 2026-07-31 14:25:26 +02:00
ADR-0006-adaptive-control-gates.md ADR-0006 + CB-WP-0009: control gates are experiments 2026-08-01 15:34:27 +02:00
ADR-0007-render-html-not-a-port.md CB-WP-0012-T03: ADR-0007 — render to HTML, and do not declare the port yet 2026-08-02 04:13:35 +02:00
ADR-0008-instrument-corrections.md CB-WP-0013-T02/T03: retire SH-3 as a gate; correct AM-4a and its target 2026-08-02 07:30:14 +02:00
ADR-0009-embed-the-js-engine.md CB-WP-0014-T01/T02: execute the JavaScript — and find AM-4b blind 2026-08-02 07:56:02 +02:00
ADR-0010-what-the-script-may-do.md CB-WP-0017: legible interaction, and the chaos window's verdict 2026-08-02 22:42:45 +02:00
ADR-0011-vendor-the-edition.md CB-WP-0021 T01/T02/T05: the engine plays its own data — AM-7 blocks 2026-08-04 00:47:56 +02:00
ADR-0012-the-design-instrument.md CB-WP-0022 T03: ADR-0012 -- the register already existed, and the rule was 2026-08-05 15:05:51 +02:00
ADR-0013-could-we-have-won.md CB-WP-0025 T03: ADR-0013 -- one world after the game, and difficulty that 2026-08-05 18:47:07 +02:00