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Laguna S 2.1 min-p evaluation

This report records the July 27, 2026, Laguna S 2.1 min-p promotion gate on an AC-powered Apple M4 Max with 128 GB unified memory, macOS 26.5.2, the official Laguna-S-2.1-NVFP4-mlx target, and the official Laguna-S-2.1-DFlash companion.

Decision

Use min-p 0.02 as the Laguna evaluation default. Keep 0 available as the official Poolside control and do not change defaults for any managed model.

The candidate preserved output volume and lexical diversity, improved the aggregate chat checks from 337/352 to 345/352, improved tool calls from 8/10 to 9/10, and retained HumanEval 3/3. The commonly suggested 0.05 cutoff produced one more raw chat-case pass but the same check total, the same tool/code pass counts, 6% fewer chat tokens, and slower chat decode. 0.10 shortened the code slice by 23% and is not the richness-preserving choice.

Quality and richness

All stochastic runs used temperature 1, top-p 1, top-k 20, automatic DFlash, and identical fixtures. Chat contains two complete 40-case repetitions; tools and code contain one complete run.

min-pChat casesChat checksMean chat latencyMean chat decodeChat tokensTool callsHumanEvalCode tokens
074/80337/3521.904 s12.26 tok/s1,7558/103/3462
0.0276/80345/3521.874 s13.63 tok/s1,8299/103/3462
0.0577/80345/3522.011 s11.01 tok/s1,6489/103/3474
0.1076/80345/3522.027 s11.60 tok/s1,7418/103/3354

The mean per-run lexical-diversity ratios were 0.541, 0.544, 0.581, and 0.554 respectively. The higher 0.05 ratio accompanies shorter output rather than a larger vocabulary corpus. 0.02 is the only candidate that improved checks while also increasing chat output volume.

Fixed-length DFlash performance

The resident release benchmark generated exactly 96 tokens per sample, five samples per mode, with mode order rotated. Stochastic target-only, forced DFlash, and automatic routing use the same normalized min-p distribution.

min-pTarget-only medianForced DFlash medianForced acceptanceAutomatic medianAutomatic acceptance
026.86 tok/s19.46 tok/s8.7%25.17 tok/s15.5%
0.0224.40 tok/s17.26 tok/s10.3%23.08 tok/s13.0%
0.0524.26 tok/s16.45 tok/s11.1%23.52 tok/s15.5%

Every automatic sample triggered the acceptance-aware fallback. Min-p does not turn stochastic DFlash into a speed win on this fixture; its benefit is quality filtering. Automatic routing remains necessary to bound the speculative regression. Greedy generation is unchanged and retains the separate, high-acceptance DFlash acceleration result.

Correctness boundary

Min-p is applied after top-k/top-p, filtered tokens receive exactly zero categorical mass, and the remaining distribution is renormalized. Laguna DFlash consumes that same distribution for draft sampling, target acceptance, and positive-residual rejection recovery. Focused tests cover threshold semantics, composition, greedy invariance, exact zero support, GPU/probability sampler agreement, and DFlash rejection correction. The official checkpoint contract/kernel suite passed 28/28 after adding the stop-on-EOS regression.

Stochastic target-only and speculative runs are distribution-equivalent, not byte-identical draws. Byte fingerprints remain the exactness gate for greedy fixtures; stochastic correctness is established by the shared normalized distribution and rejection-correction tests.

Released under the MIT License.