clay-borg/evidence/CB-EV-0020-solve-legality.md

CB-EV-0020 — a gate moved the rule, and the report was wrong

CB-WP-0023 T03. Measured 2026-08-04 at 46c2fb6+. Pass kind product, tier S (chaos d8 = 6, no override). Declaration 6 of chaos window 2.

---

1. How long the inert move survived, and what it cost

SOLVE has been offered where it could do nothing since legal_commands was written — nineteen passes. It cost one maintainer three consecutive rounds of a real game, playing the same move and watching nothing happen, with no explanation on the page.

It was not found by a test. It was found by a person playing, and then only because they said so.

2. The rule ended up somewhere other than where I put it

I implemented the ruling in legal_commands — the offer layer — and it worked: SOLVE stopped being offered, four conditions, four tests.

Then the AM-1 coverage gate failed the build: 58/59, GR-P05 uncovered. Scenarios are what cover a rule, and scenarios drive validate, not the offer layer.

That is what showed the rule was in the wrong place. A rule enforced only by the offer is enforced only for clients that ask what is legal. The browser would have been filtered; a scenario file, a bot, or any future client that constructs a command directly would have walked straight past it.

Once GR-P05 moved into validate, every condition in legal_commands was dead code — and the layering test I had written for a different reason said so in exactly those words: "validate now rejects claimed — drop the filter." The offer layer is back to one arm for Investigate and SOLVE together, and it gets the rule for free because it filters candidates through validate anyway.

The gate did not catch a bug. It caught a design error, which is a better return than it was built for.

3. The reported case was not the one I reported

CB-WP-0018, CB-EV-0016 and the message to ground-game all described the defect as SOLVE offered on a face-down Problem.

Measured: validate already rejected face-down. It never was offered.

Problem 1 is the Surface Problem and is face-up from the deal (GR-S01), so the maintainer's three inert SOLVEs were the hand case — holding no Clarify for a Clarify Problem. I inferred "face-down" from the play report without checking which condition was actually blocking, and then told the game's designer.

The ruling covers both sub-cases, so nothing it says is invalidated and no re-ruling is needed. But a ruling was requested on the strength of a description that was wrong, and this is the second time in three passes that a premise I supplied reached ground-game unchecked — the first being the "12 points available" that voided GR-E01.

Two of two. The pattern is not that the analysis is careless; it is that a claim gets sent the moment it is interesting, and checked afterwards. That is the same shape as unexecuted verification, one step further out: not an unverified belief acted on, but an unverified belief published.

CB-WP-0022's "no finding without its reproduction" rule would have caught both. GD-0001 already carries its reproduction; this pass is the argument for making that the standard rather than the exception.

4. What the four conditions cost to prove

Each is asserted on its own, because a single "SOLVE is filtered" test passes with three of four implemented and nobody learns which.

mutation	result
drop the claimed check	solve_is_not_offered_on_an_already_claimed_problem red
drop the hand check	solve_is_not_offered_without_a_matching_solution_in_hand red
invert the layering assertion	validate_enforces_all_four_solve_conditions red

An earlier mutation run reported three survivors and was wrong: the replacement strings did not match the source, so nothing was mutated. The run proved nothing and looked like a result — the harness-does-nothing class, in my own hands, caught only by checking that the file changed.

No scenario encoded the bug. All 25 passed unchanged; the 26th covers GR-P05.

5. Cost

pass	kind	responses	cost	$/response
CB-WP-0022	product	in flight — T01 only
CB-WP-0021	product	12	$5.06	0.422
CB-WP-0023	product	provisional — not quoted

CB-WP-0022 is still active and cannot be quoted as settled; CB-WP-0021 is ready with its declaration and correction committed and no implementation, which is what $5.06 buys. Read by re-running make status at the moment of writing.

6. Open

• CB-WP-0021 (the edition import) is unstarted and now partly redundant: GR-P05's suit check makes the stand-in's cycled suits load-bearing, so importing real required_solution values changes which Problems each hand can solve. It should be re-read before it is run.
• CB-WP-0022 T02 (adversarial review) is next, and §3 has just handed it a second data point.
• GROUND-WP-0004 — GR-E01's ruling reopened on corrected numbers, with the maintainer's unwinnable 3-player games as evidence.
• Chaos: 6 of 12 in window 2, one override, changed nothing.