One armourAgainst, in the authority, shared with the harness (R-257)

Left open by R-256. Two rules decided how a hit meets armour — armourAgainst (a critical
ignores it, a special halves it, rounded down) and damageAfterArmour (what is left never
goes below zero). Both lived in ringbrp.mjs, which is the game. Neither lived in
rules.mjs, which is the authority, so the guard that forbids redefining a rule had
nothing to forbid. tools/simulate.mjs applied armour from its own inline copies of both,
as it had since it was written.

They agreed, which is the whole point. Nothing published was wrong and no guard could
have said they were two things rather than one. But every number in BESTIARY.md, every
row of the lethality baseline and every measurement quoted from R-251 onward comes out of
that harness: change how a special hit meets armour and the game changes, the numbers
describing the game do not, and all nine guards still pass. Same shape as ddc4f99, with
no tolerance to blame and no reason it would ever have surfaced.

Both rules now live in rules.mjs. ringbrp.mjs imports and re-exports them because they
are public API at game.ringbrp. The simulator imports them. Verified live in the world
that game.ringbrp.armourAgainst and the rules.mjs export are the same function object,
not two that agree.

Proof it changed nothing: check-lethality replays 47 creatures over 2000 fights each and
every one fights exactly as recorded — no tolerance, no drift — across roughly four
million resolved attacks, all of which now go through the moved rule.

check-rules fails any file outside rules.mjs that halves armour or subtracts it inline,
naming file and line. Negative-tested by restoring the harness's original three lines
verbatim (both patterns fire) and by redefining armourAgainst in ringbrp.mjs, which the
name-based guard now catches because the rule finally lives somewhere it belongs to.
Arriving in rules.mjs also tripped the spot-check requirement immediately: eight new
spot-checks, and what a special does to hide 9 is now written down once.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

system.json

@@ -2,7 +2,7 @@
   "id": "ringbrp",
   "title": "The Custodians",
   "description": "A Basic Roleplaying game of agents who cross the crossing to contain what should not be there — and who come back a little less from here each time.",
-  "version": "1.7.11",
+  "version": "1.7.12",
   "compatibility": {
     "minimum": 13,
     "verified": "14.364"