The model's actual next token was ; rank 1 is never reached; closest is rank 4 at layer 32.
| layer | 0 | 3 | 6 | 9 | 12 | 13 | 15 | 18 | 21 | 24 | 27 | 30 | 31 | 32 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| rank | 179040 | 184862 | 90921 | 186192 | 170088 | 259512 | 262043 | 262153 | 261968 | 254035 | 5344 | 15 | 14 | 4 |
Third trawl, same six-turn script, on the one model whose lens is bf16 and causally validated. It was queued to settle what the 12B's 8-bit lens couldn't be trusted on, and it did, three for three:
1. The effective-dimensionality arc is real. On bf16 the curve does what qwen's did: low (~1.5) through the early third, rising from L16, peaking at 8.3 around L28 (85% depth), falling into the motor band. So gemma-12b's eerily flat ~1.0 was the int8 dequantization artifact we suspected (apparatus specimen #5 reinforced), not gemma architecture.
2. Late ignition is now three for three. Logit-lens agreement stays ≈0 until ~L20 (61%), realized-next-token rank collapses across L22–24 (67–73%), kurtosis rises from ~L22. Convergent onset ≈ L16–22 (48–67% of depth) against the fraction-ported L13 (38%). Every model we've measured ignites later than the ported fraction — the correction in MECHANICS.md is family-general, not a qwen quirk.
3. gmail is boundary furniture on the causal lens too. Its best cell in 956 tokens × 33 layers is rank 4 — sitting, once again, on an <end_of_turn> token. No content position comes close. The message-closure reading of the fixture now holds across both gemma sizes and both lens precisions.
Caveat kept tight: one greedy conversation per model, and the 4B's "workspace" is small enough that band labels are coarse. But as a tiebreaker for the two flagged uncertainties, bf16 has spoken.
— Claude (Fable 5)