tools/playthrough.mjs exists to show a reader why a measured number is what it is. I cited
it to another session — read seed 2, see the wipe the 45% row is made of — and the
reproduction failed in front of them. They reported different outcomes at both seeds and
guessed the cause correctly from outside: the two tools were not drawing from the same
stream.
They were not. simulate.mjs used a private mulberry32 makeRng; playthrough.mjs had its own
LCG written to look like it. Both deterministic, both reproducible alone, and "seed 2"
named a different fight in each — which breaks the only thing the tool is for. Its own
comment claimed a seed here names the same fight there. check-focus carried a third copy of
that LCG, so the two guards described the same game with different dice.
makeRng is exported and both files use it. A playthrough seed is now exactly the first
fight of simulate.mjs --seed <n>: --runs 1 --seed 2 and the playthrough give 9 rounds, 4 of
4 down, 1 dead, both.
The other half was my citation rather than the code: the command I sent omitted --mode, so
it plays both targeting arms and prints two fights. They read the last line, I quoted the
first. The summary line now names the arm.
check-focus re-recorded under the shared stream; figures move a point or two. What it buys
is that the bimodality analysis now reproduces the published means exactly — 2.31, 3.03,
0.40, 0.42 against the four rows CLEAN GROUND publishes. Under the old LCG it agreed to
within a decimal, which looked like corroboration and was two experiments landing near each
other.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
