core/docs/analysis/oov-grounding-determinism-morphology-affinity-collapse.md

OOV Grounding Determinism: Morphology-Affinity Collapse

Map

Three candidate explanations were checked in the OOV grounding path:

• Unseeded random synthesis: not found. ingest/gate.py did not call random or np.random for unknown-token construction.
• Python hash / hash-seed ordering: not found on the active construction path. The compiler feature rotors and the new fix use SHA-256, not hash().
• Transient index or vocabulary process state: not the failing source. Transient insertion happens after construction; it did not feed the failing field bytes.

The exact failing source was _best_decomposition() in ingest/gate.py. When a token had no exact prefix/root/suffix decomposition, the function fell back to a root-affinity scan over mounted morphology. _ground_unknown_token() then used that selected root as the whole OOV point whenever no prefix/suffix operators were applied. The OOV token's byte content did not enter the versor at all in that generic path.

Observed RED repro:

• probe_ingest(["<oov>"]).F.tobytes() was already stable across fresh contexts.
• probe_ingest(["xyzzy_unknown_token_12345"]).F.tobytes() and probe_ingest(["zzq-no-morph-019"]).F.tobytes() were byte-identical because both were assigned the same affinity root, ἀποκρίνομαι, with no operators.

Build

The fix lives only at the sanctioned ingest boundary, ingest/gate.py.

• Exact morphology still uses the known root when the OOV token has a real prefix or suffix decomposition.
• Empty-prefix/empty-suffix affinity fallback is no longer treated as structural grounding. Generic OOV starts from the identity versor instead of inheriting an arbitrary morphology root.
• Every OOV transient receives a token-byte delta: sha256("oov:token:v1" || token_utf8) selects three small negative-bivector Spin rotors and records a token:sha256:<prefix> audit operator.
• Morphology prefix/suffix deltas in the OOV path now also use negative-bivector Spin rotors rather than the compiler's feature rotors.

No realization code and no vault code were touched.

Justify

The corrected intrinsic space is the token's stable byte identity composed with any real morphology decomposition. The previous fallback projected unknown tokens into a borrowed root space; that collapsed unrelated symbols and made the generic OOV point a function of mounted vocabulary shape rather than token content.

Closure is preserved by construction: each new delta is cos(theta) + B sin(theta) where B is one of (6, 7, 8, 10, 11, 13), the negative bivectors in Cl(4,1). These are Spin factors, so composing them with a closed root or with the identity remains on the versor manifold. The OOV constructor checks versor_condition(versor) < 1e-6 and raises if construction violates the contract; it does not normalize, unitize, grade-project, or repair the transient after the fact.

The field-level inject() holonomy boundary remains unchanged and continues to own prompt-field closure.

Verification

Initial RED:

uv run python -m pytest tests/test_oov_grounding_cache.py::test_generic_oov_probe_is_byte_stable_across_contexts_and_restore -q
# FAILED: two distinct generic OOV tokens produced identical field bytes

Targeted GREEN after the fix:

uv run python -m pytest tests/test_unknown_token_ingest.py tests/test_oov_grounding_cache.py -q
# 8 passed

Final verification:

uv run python -m pytest tests/test_unknown_token_ingest.py tests/test_oov_grounding_cache.py -q
# 8 passed in 3.26s

uv run python -m pytest tests/test_unknown_token_ingest.py tests/test_oov_grounding_cache.py tests/test_oov_pipeline.py tests/test_oov_surface.py tests/test_pack_grounded_unknown.py tests/test_partial_surface.py tests/test_cold_start_grounding_lane.py tests/test_language_pack_runtime.py tests/test_language_pack_cache.py tests/test_language_pack_load_safety.py -q
# 142 passed in 75.09s

uv run python -m core.cli test --suite smoke -q
# 90 passed in 114.00s

uv run python -m core.cli test --suite cognition -q
# 121 passed, 1 skipped in 55.84s

uv run python -m core.cli eval cognition
# intent_accuracy: 100.0%
# term_capture_rate: 100.0%
# surface_groundedness: 100.0%
# versor_closure_rate: 100.0%

uv run python -m core.cli eval cognition --json
# all 13 case records had intent_correct=true, surface_contains_pass=true,
# and versor_closure=true; this lane does not emit a separate wrong counter.

Wrinkle: the repository declares a core console script in pyproject.toml, but uv sync reports that entry points are skipped because the project is not packaged in this checkout. The exact uv run core ... form therefore fails to spawn core; the verified equivalent is uv run python -m core.cli ....