Operator, exact utterance: "Deciding to hold to gua does not cost anything
operationally and the case for ULA over gua is not very strong. Let's stay with
gua". Recorded as RULING NOTE 2026-08-01 -- D-139.

RULED: ruling B STANDS, unchanged in substance. The GUA carve table is confirmed,
the ULA /48 stays RETIRED for VR1, the D-101/D-111 amendments hold, and Phase-2
execution of D-139 is UNBLOCKED.

WHAT CHANGED IS THE RATIONALE OF RECORD. The RFC 6724 precedence argument is
STRUCK IN PLACE in D-139 -- quoted, with the measurement that kills it and a
pointer to the capture, marked DO NOT CITE IT. Struck rather than deleted on
purpose: deleting it would leave a future session free to re-derive an argument
that has already been considered and refuted. The block also warns against the
near-miss rescue -- glibc 2.35 DOES carry fc00::/7 in default_labels[] (label 6),
which drives SOURCE-selection rules 5/6, a different mechanism from destination
precedence; finding it does not resurrect the struck claim.

Ruling B now rests on two project-constraint arguments -- conformance (Willamette
and VR0 DC0 are already full GUA; VR1 was the outlier) and MINIMIZE DELTA TO
ROOSEVELT -- plus the operator's recorded reasoning that GUA costs nothing
operationally. MADE EXPLICIT because it was not visible before: on glibc 2.35 GUA
buys NO address-selection advantage on the two dual-stack planes; ULA would have
won equally at 40. Anyone later reasoning "GUA was chosen so v6 would beat v4" is
reasoning from the struck argument.

NEW STANDING RULE, recorded on D-139 because it generalises: the repo's citation
rule (open it, check STATUS and DATES) was FOLLOWED here and was NOT ENOUGH. The
citation was real, current, correctly quoted and correctly understood, and still
wrong, because nobody checked whether the IMPLEMENTATION follows the standard.
For a STANDARDS citation, add a third check -- confirm the deployed software
implements it, at the deployed version. An RFC is not a description of your system.

Staged by explicit path; an agent's in-flight files (netbox/d139-gua-carve.py,
tests/d139-gua-carve/, docs/audit/d139-carve-dryrun-20260801.txt) are deliberately
NOT included. repo-lint 0 fail.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf