diff --git a/amethyst/plans/2026-09-21-deck-0003-sno.md b/amethyst/plans/2026-09-21-deck-0003-sno.md
index b7411bee74..42580406d2 100644
--- a/amethyst/plans/2026-09-21-deck-0003-sno.md
+++ b/amethyst/plans/2026-09-21-deck-0003-sno.md
@@ -239,6 +239,49 @@ mode), `orient` (winding faces outward so a lit bench can paint backfaces dark),
 exists nowhere in the DECK), `pose`, `scale`, `hsv`. None of it is needed to *read* an
 object. All of it would be needed to build a workshop, which is D3's argument.
 
+### 2.5a Checked against the reference implementations, not only the spec
+
+§8.10 says its two reference implementations are "pinned to one set of golden
+vectors", and the first pass built the avatar ladder from the section's
+pseudocode instead — which is the same text both implementations read, so
+agreement with it proved nothing about agreement with them. Closed since:
+`tests/fixtures/avatar_work.json` from cyberspace-cli is now a test, and **all
+eight vectors pass**. The two fixture sets (cyberspace-cli and cyberspace-core)
+carry the same eight names with identical `reach` and `required` throughout, so
+the "one set" claim holds and checking either checks both.
+
+The vector that earns its keep is **"half gibson, ticks"**: a vertex of
+`[-1, -1, -1]` with ticks `[60, 60, 60]` is **-0.5** of a unit, not -1.5,
+because the whole part is the floor and the ticks count up from it. An
+implementation that takes the magnitude before adding the ticks prices that
+avatar at three times its reach and passes every other vector in the set.
+
+`verify_avatar_work` in the Python reference also confirms the shape of the
+payment check independently: committed ≥ required **and** zeros ≥ committed, as
+two separate conditions with distinct failure reasons — which is what §5 of this
+plan's own note about `Event.pow()` is about.
+
+**The Python reference is stale on the avatar kind, and we do not follow it.**
+
+| Implementation | Avatar kind |
+| ---- | ---- |
+| `CYBERSPACE_V2.md` §8.10 | **11333** |
+| cyberspace-core (TS, 2026-09-14) | 11333 |
+| ONOSENDAI (the client) | 11333 |
+| cyberspace-cli (Python, 2026-09-07) | **33331** |
+
+The Python CLI predates the kind move by a week and still calls 33331 the avatar
+kind, which DECK-0003 has since given to standalone objects. Run against the
+current network it would refuse a conformant avatar as `not-an-avatar`, and
+would treat one of the seven published `kind 33331` objects as an avatar and
+demand proof of work of it. We follow the spec and the two current
+implementations.
+
+Nothing else in the Python CLI overlaps this work: it implements no §1.9, no
+palette and no mode — its only SNO surface is the avatar ladder. It does
+implement the `kind 33330` bag (encrypt/decrypt), which is the part we
+deliberately do not.
+
 ### 2.6 The two reference implementations disagree, and I checked which way
 
 The DECK's conformance note says `sno-reference.py` and ONOSENDAI's TypeScript reader