#000070: dav1d review 2026-06-01 — GO with rewrite (AnchorN, not Anchor6)

Folds dav1d's 1904-line review verdict into the ticket as §0 (new),
preserves §§1-8 as the design log of the original Anchor6 proposal
that was reviewed. Status flips from "open · awaiting dav1d review"
to "open · dav1d GO with rewrite · spec revision pending before any
kernel ships."

Verdict matrix:
  ✅ GO: generic AnchorN substrate primitive (not fixed Anchor6)
  ✅ GO: Joseph6 as the first registered default grammar (not THE
        ontology)
  ✅ GO: deterministic object-state canonicalization
  ✅ GO: axiom/physics-loaded WorldDimensionGrammar as the scalable
        path
  ❌ NO-GO: hard-coding H₁..H₆ as final ontology
  ❌ NO-GO: runtime LLM-decided dimensionality (axioms MAY propose,
           only deterministic validators may accept; grammars must
           freeze via grammar_hash before proof-path use)
  ❌ NO-GO: framing this as a "semantic verifier warrant"
  ❌ NO-GO: relation/event/place/agent_trace in this ticket
  ❌ NO-GO: SQL persistence at Phase 1

Critical technical corrections:
  - H₁ MUST use uint256, not uint64 (octree position entropy at
    depth >8)
  - Rotation mapper is map_rotation_euler_ypr(), NOT "SO(3)"
    (review §17 — quantized Euler triple, no continuous SO(3))
  - Canonical record carries grammar_hash + axiom_pack_hash +
    manifest_hash + seed_hash alongside the per-dimension values
  - Missing privacy.class = HARD reject (no PUBLIC fallback)
  - spatial-anchor-object@v1 folds into canonicalization_version
    only — no new audit_mode token, no verifier_policy_hash bump

Corrected package layout:
  arborist/substrate/spatial_anchor.py   (AnchorN, split_anchor_n)
  arborist/world/grammar.py              NEW — WorldDimensionGrammar
  arborist/world/pi_star/object.py       (derive_world_object_record
                                          + 5 mappers)
  arborist/pi_star/spatial_anchor_object.py  NEW — registry adapter
  bench/fixtures/spatial-anchor-object/known-answer-tests.jsonl
  tests/test_spatial_anchor.py
  tests/test_world_dimension_grammar.py
  tests/test_pi_star_spatial_anchor_object.py

Implementation NOT started — arborist/world/__init__.py STATUS still
"namespace_reserved"; only bench/spatial_anchor_validation.py
(pre-review empirical bench, commit 55b651f) on disk. Review arrives
at the right moment: no production code committed against the original
Anchor6 spec yet, so the AnchorN reframe lands in the spec before
the wrong primitive ships.

Full review archived at:
  docs/dav1d-reviews/000070-spatial-anchor-pi-w-object--2026-06-01.txt

Five of ten original open questions resolved by the pre-review bench
(Q1/Q2/Q3/Q8/Q9); review answers Q4/Q5/Q6/Q7; Q10 (paper-amendment
wording) is the only remaining open question — substrate paper text
needs revision to introduce AnchorN + grammar layer instead of fixed
Anchor6.

docs/tickets/ticket-000070-spatial-anchor-pi-w-object.md

@@ -1,7 +1,14 @@
-# Ticket #000070 — Spatial-anchor π*_w_object (Joseph 6-dim determination kernel)
+# Ticket #000070 — AnchorN + π*_w_object: deterministic world-object canonicalization
 
-**Status:** open · awaiting dav1d review + fox go/no-go ·
+**Status:** open · **dav1d GO with rewrite (2026-06-01)** · spec
-pre-review empirical bench shipped in `55b651f` (see §7a)
+revision pending before any kernel ships. Pre-review empirical bench
+(`bench/spatial_anchor_validation.py`, commit `55b651f`) already on
+disk; no implementation kernel started (only the namespace stub at
+`arborist/world/__init__.py` exists, `STATUS = "namespace_reserved"`).
+**Original title kept in the design log:** "Spatial-anchor π*_w_object
+(Joseph 6-dim determination kernel)". §0 below carries the corrected
+spec; §§1-8 preserve the ORIGINAL Anchor6 proposal as the historical
+record of what was reviewed.
 **Opened:** 2026-05-31
 **Scope:** Pin the operational spec for **π*_w_object** — the first
 verifier kernel of v7-W. Implements **Joseph (@TrudoJo)**'s 6-dimension
@@ -43,7 +50,163 @@ Joseph (@TrudoJo, original framework author), #000013 follow-up,
 
 ---
 
-## 1. Problem statement
+## 0. Dav1d review verdict (2026-06-01) — GO with rewrite
+
+Full review at `docs/dav1d-reviews/000070-spatial-anchor-pi-w-object--2026-06-01.txt`
+(1904 lines). Headlines below; §§1-8 stay unchanged as the design log
+of the original Anchor6 proposal that was reviewed.
+
+### 0.1 Verdict matrix
+
+| | | |
+|---|---|---|
+| ✅ GO | generic **AnchorN** substrate primitive | not fixed Anchor6 |
+| ✅ GO | **Joseph6** as the first registered default grammar | not THE ontology |
+| ✅ GO | deterministic object-state canonicalization | the actual Phase 1 win |
+| ✅ GO | axiom/physics-loaded `WorldDimensionGrammar` | the scalable path |
+| ❌ NO-GO | hard-coding H₁..H₆ as final ontology | freezes the substrate |
+| ❌ NO-GO | runtime LLM-decided dimensionality | breaks reproducibility |
+| ❌ NO-GO | framing this as a "semantic verifier warrant" | commitments ≠ warrants |
+| ❌ NO-GO | relation/event/place/agent_trace inside this ticket | scope-creep |
+| ❌ NO-GO | SQL persistence in Phase 1 | namespace-reserved kernel only |
+
+### 0.2 Architectural reframe
+
+Replace the fixed Anchor6 primitive with **generic AnchorN** driven
+by a frozen `WorldDimensionGrammar`. The grammar is a deterministic
+manifest declaring N and the N region→mapper bindings. Joseph6
+becomes a *named* grammar instance (`name="joseph6", version="v1"`),
+not THE substrate.
+
+**Critical correction on the "axioms decide N" intuition:**
+
+  - Axioms MAY *select* the grammar (LLM may *propose* candidates).
+  - Only *deterministic validators* may accept them.
+  - Accepted grammars are canonicalized, hashed, KAT-tested, versioned.
+  - **Grammars must be FROZEN before proof-path use** — `grammar_hash`
+    folds into the manifest. Runtime LLM dimensionality is the
+    failure mode dav1d explicitly NO-GOs.
+
+### 0.3 Technical corrections (load-bearing)
+
+  - **§16 — H₁ MUST use uint256, not uint64.** The original
+    `map_octree_position()` truncation loses entropy at depth >8
+    octants. uint256 preserves the full 32-byte region. Same lesson
+    propagates to the other quantized dimensions.
+  - **§17 — Do NOT overclaim SO(3) on rotation.** The original spec
+    called H₃ a "quantized SO(3)" mapper; dav1d notes this is a
+    quantized Euler ypr triple — name it `map_rotation_euler_ypr()`
+    so consumers don't assume continuous SO(3) coverage.
+  - **§18 — Canonical object output shape:** the record carries
+    `grammar_hash`, `axiom_pack_hash`, `manifest_hash`, `seed_hash`
+    alongside the per-dimension quantized values. All four hashes
+    are required for replayability across grammar versions.
+  - **§19 — Privacy fail-closed:** missing `privacy.class` in
+    manifest = HARD reject (don't fall back to PUBLIC).
+  - **§20 — Hash/cache discipline:** spatial-anchor-object@v1 folds
+    into `canonicalization_version` only; no new `audit_mode` token,
+    no `verifier_policy_hash` bump.
+
+### 0.4 Corrected package layout (was §13 of the review)
+
+```
+arborist/substrate/spatial_anchor.py
+    AnchorN
+    split_anchor_n()
+    SPATIAL_ANCHOR_VERSION
+    PLACEHOLDER_SPATIAL_SEED
+
+arborist/world/grammar.py                  (NEW)
+    WorldDimensionGrammar
+    canonical_grammar_bytes()
+    grammar_hash()
+    validate_grammar()
+
+arborist/world/pi_star/object.py
+    derive_world_object_record()
+    map_octree_position()         # uint256 — see §16
+    map_scale_level()
+    map_rotation_euler_ypr()      # not "SO(3)" — see §17
+    map_symbol_table_index()
+    map_passthrough_hex()
+
+arborist/pi_star/spatial_anchor_object.py  (NEW)
+    registered π* adapter
+        name = "spatial-anchor-object"
+        version = "v1"
+        canonicalize(raw: bytes) -> bytes
+
+bench/fixtures/spatial-anchor-object/known-answer-tests.jsonl
+tests/test_spatial_anchor.py
+tests/test_world_dimension_grammar.py
+tests/test_pi_star_spatial_anchor_object.py
+```
+
+The split moves **registry-facing canonicalization** to
+`arborist/pi_star/` and keeps **v7-W domain logic** under
+`arborist/world/`. AnchorN itself stays substrate-level alongside
+`anchor_prg.py` since it's the generic key-derivation primitive.
+
+### 0.5 Phase 1 deliverable (corrected)
+
+```
+1. generic split_anchor_n()                     — substrate, hash-pinned
+2. Joseph6 grammar instance                     — frozen, KAT-tested
+3. π*_w_object canonicalizer                    — registry slot
+4. KATs at bench/fixtures/spatial-anchor-object/known-answer-tests.jsonl
+5. Tests (3 modules above)
+6. Substrate-paper amendment citing Joseph (@TrudoJo)
+7. NO SQL
+8. NO new audit_mode
+9. NO verifier_policy_hash change
+```
+
+### 0.6 Relationship to #000071 (cross-ref)
+
+Dav1d §22 confirms #000071 (world-bridge grammar) is the right
+sibling: bridges connect different `WorldDimensionGrammar` instances
+across chains. AnchorN + grammar identity is what the bridge layer
+identifies; without grammar-as-first-class-object, bridges have
+nothing to anchor.
+
+### 0.7 Five dav1d open-questions answered by measurement, five still open
+
+§7a of this ticket already cited the pre-review empirical bench
+(`bench/spatial_anchor_validation.py`) resolving five of the ten
+original open questions (Q1 seed source / Q2 segmentation / Q3
+octree mapper / Q8 endianness / Q9 KAT adversarial vectors). The
+review preserves those resolutions and reframes Q4/Q5/Q6/Q7/Q10:
+
+  - **Q4 scope split** — answered: object alone, NO relation/event/
+    place/agent_trace in this ticket. AnchorN handles N=6+ kernels
+    in future tickets.
+  - **Q5 privacy fail-closed default** — answered: HARD reject on
+    missing `privacy.class`.
+  - **Q6 `audit_mode` discipline** — answered: spatial commits are
+    not warrants, no new token.
+  - **Q7 manifest-validator timing** — defer to grammar validation
+    step in `arborist/world/grammar.py:validate_grammar()`.
+  - **Q10 paper-amendment wording** — still open; substrate paper
+    text needs revision to introduce AnchorN + grammar layer
+    instead of fixed Anchor6.
+
+### 0.8 What changes for the implementer
+
+The original §3 "Recommendation" + §4 "Implementation sketch" name
+specific functions (`segment_anchor()`, fixed-6-region split, etc.).
+Those stay in the design log as reference; **what actually ships
+follows §0.4 above** — `split_anchor_n()` with grammar-driven N,
+`WorldDimensionGrammar` class, registry-addressable π* adapter.
+
+The original §7a empirical bench remains valid as evidence — it
+validated the HMAC-SHA-512 expansion's avalanche / uniformity /
+domain-separation properties, which are unchanged by the AnchorN
+generalization (N just changes the loop count; the per-region
+properties measured stay identical).
+
+---
+
+## 1. Problem statement   *(original design log — what was reviewed)*
 
 ### 1.1 What #000013 left undefined