The operator's question -- "are we mirroring the assigned IPv6 octet with the last
IPv4 octet like we did before?" -- exposed two errors in what this session recorded.

(i) I said MAAS static assignment "needs only the subnet, which now exists". Wrong:
mode=static means an EXPLICITLY CONFIGURED address, which is how the Stage-4 carve
set the 90 v4 links. Measured -- all 18 Ready nodes carry ZERO IPv6 links, while
their v4 side is correctly octet-mirrored. So VIPs are mirrored (156 apex objects)
and nodes are not; 108 assignments are owed. (ii) v6 gateway_ip and dns_servers are
unset on all 12 v6 subnets, unnamed before I called step 3 complete. That
"complete" is withdrawn -- the MAAS/apex/lib-net population stands, the node layer
is the remaining half.

D-101 gains its GOVERNING RATIONALE, quoted verbatim, because it existed in no repo
surface: IPv6 unless IPv4 is NECESSARY, driven by real IPv4 sizing constraints in
future expansion -- a commercial requirement, not a preference. It records that
v4-first was DELIBERATE RISK REDUCTION so a future session does not read v4
surfaces as neglect and "correct" them; that Roosevelt has full v4 and v6 edge
transport; and that NAT64/DNS64 was considered and REJECTED on that basis -- a shim
with no Roosevelt analog, against ULA planes that are internal by design.

Node v6 carve scoped in docs/audit/node-v6-carve-scope-20260727.md: 108 assignments
mirroring each node's live v4 octet, prior art measured v4-only, blast radius
per-link and reversible, and the operator's own rationale arguing to carve BEFORE
the deploy since v6-unfriendly modules surface far more cheaply on a static
read-back than mid-bundle.

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