Arm C is NOT defined in docs/2026-09-02-k3-k4-k5-metode.md -- that file
contains no occurrence of the word, and neither Arm A nor Arm B is defined
there either. The definition implemented here was written for order
20260904T145630Z and is reported as the author's, never as a ratified one.
Arm C = Arm B's mechanical rules, plus one deterministic rule that cuts
any proposed span longer than a declared cap at the nearest paragraph
boundary at or before it, the whole document counting as one span when
the rules find no boundary at all.
One rule and not two, on purpose. The two failure modes the K2 rebuild
measured -- a PDF with no outline (Bilag 9.1, 217 472 characters) and a PDF
whose headings are its table of contents, so the trailing segment absorbs
the body (Bilag 3.1, Bilag 1) -- are the same failure of SIZE, and a second
rule aimed at each would confound which one moved the number.
`--max-segment-chars` defaults to 0, which is OFF: the artifact is then
byte-identical to Arm B's, pinned by a test that writes both and compares
bytes. The standard profile does not move, and the K2 bundle a consumer is
running against right now is not rebuilt.
What Arm C deliberately does NOT change: the region before the first
candidate is still covered by no segment. That is a real coverage defect --
the K3 baseline's blind rater named it -- and fixing it here would put two
changes behind one measurement.
A part carries TWO rule names in `derived`: the heading rule that opened the
span, and `rule:size-split` for the cut. Dropping the first would make a
part traceable to arithmetic and nothing else.
Tests first: 13 red, then green. 1055 -> 1068.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>