[heydryft]

The headline

When instruction-bound, bits-per-weight CANCELS OUT of the throughput equation — achieved = 23,409/X at B=256, bpw-invariant.

The 2-bit format does not buy speed. It buys the model existing on one card: 74 GB vs MXFP4's 151 GB and FP8's 284 GB, neither of which fits an H200. SGLang's V4 numbers run on two GH200s. No competitor format puts this model on one card at all.

⇒ The capacity wedge is already won by the format. It is a DIFFERENT claim from speed, where we are 15–25× behind. They never share a table — conflating them produced the "16,600 → 1,477" framing Jish rejected.

What lands

file	change
00_RESUME_HERE.md	session-8 CLOSE block at the top (headline · measured · 13 retractions · 7 sequencing gates · taxonomy corrections); existing content left intact, stale claims fixed in place
FACTS.md	new §2026-08-19 measured block + the retraction table; the 0.4194 acceptance row now carries the 0.485 retraction
KERNEL_RULES.md	seven new rules at the top, each paid for
TAXONOMY.md	four corrections in place + "Arc has never run a forward pass on more than one GPU"
COMPETITIVE_TEARDOWN.md	the largest carrier of retracted claims — struck in place, not appended to

Measured this session — zero GPU hours

• Trellis inst/weight, COMPILED (nvcc -cubin, CUDA 12.4.131, inner loop by unroll differencing): shipped K4/V2/L16 15.125 sm_90 → K8/V4/L12 + row-scale hoist 4.375 = 3.46× fewer instructions, and still 3.1–3.9× short of the 1.13–1.41 budget. Both LUT geometries are exactly 32,768 B — under the 48 KB static limit, no cudaFuncSetAttribute; occupancy 62.5% (not the predicted 31%), register-limited.
• V4 KV over-retention: 361.4 MB/seq → 6.35–11.96 MB/seq at 8k = 30–57×; B=32 @ 8k 11.57 GB → 0.38 GB.
• Launches: 9,131 → 8,650/token; casts 1,571 → 1,141.
• Frozen Gumbel: 1 distinct token before, 64 after (512 draws, flat 64-token distribution).

Retractions — 13, four of them main's

The ceiling claim (1 bpw scored against a 2-bpw budget), p ≈ 0.485 (fitted, never in the tree — real is 0.4194), the 2-bit-draft-head explanation (refuted by commit order), ×5.53 → ×1.55, PD disaggregation → it is the metric definition, and the re-bake cost inverted (~8× more, ~$30). Full table in all three docs.

Taxonomy corrections

Expert parallelism IS on master (PR #89, 610c4506b) — the gap is a missing CLI flag, not the feature. mark_unreachable, the registry for dark features, is itself dark (4 of 6 site strings drifted). CrossPrefixMeter is not dead. head_dim 512 is not the blocker — 448 is. Arc has never run a forward pass on more than one GPU.

Note on the four added files

00_RESUME_HERE.md, FACTS.md, KERNEL_RULES.md and COMPETITIVE_TEARDOWN.md have never been versioned — they lived only in the agent memory directory, which has no backup. The repo's TAXONOMY.md had already drifted a revision ahead of the live copy (the TurboQuant box), which is exactly the failure the new sync note in TAXONOMY.md exists to make visible. Both copies are byte-identical as of this commit. Revert this half if the mirror is unwanted; the TAXONOMY.md corrections stand on their own.

Cross-links to memory/mission/CENSUS_SESSION8.md and memory/mission/LADDER_POST_CENSUS.md resolve once docs/census-session8 merges; every reference names that branch until then.

No code, no CI, no cargo fmt. Docs only.

🤖 Generated with Claude Code

https://claude.ai/code/session_01SpVNMpb13HkUXqSqbN1o9H

[github-actions]

Code Metrics Report

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 (Total)                             4463         4298           92           73
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 Markdown                199        39948            0        30698         9250
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 (Total)                            45713         4681        31240         9792
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 Rust                    671       324354       279943        15914        28497
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 (Total)                           351961       280414        39731        31816
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