Qwen3.8-Flash-Next-MTP-Drafter-GGUF

Qwen3.8-Flash-Next MTP draft head (GGUF)

Standalone GGUF packagings of the Qwen3.8-Flash-Next multi-token-prediction (MTP) head, for speculative decoding with gmlx on macOS / Apple Silicon.

Initial GGUF conversions of this model (unsloth and others) drop the mtp.* tensors: llama.cpp does not yet implement the qwen4exp MTP head, so its converter discards them, leaving no self-drafter. These files restore the head. The tensors were extracted from the official bf16 safetensors release (Qwen/Qwen3.8-Flash-Next, revision main) and re-encoded, unmodified; either file pairs with any quantization of the base model GGUF.

Files

One MTP layer each (attention + 512-expert MoE + hyper-connection mixer) plus fc/norm glue, 33 tensors. In Q4_K_L the expert down projections stay q8_0 because their 640-wide rows do not divide the 256-wide q4_k superblock. Full sha256 values and per-tensor shard sources are in the .provenance.json next to each file.

Usage

Requires gmlx. llama.cpp is not expected to load these files; the model support they would need does not exist there as of 2026-08-26.

Place one file next to the base model GGUF and gmlx autodetects it:

gmlx serve <base-model>.gguf --speculative

Notes:

• Place exactly one drafter file next to the base model. gmlx detects it by GGUF header (arch qwen4exp-mtp), not by filename; with two present the lexically first wins.
• Works with any base quantization (UD-Q3_K_XL, UD-Q4_K_XL, ...); the drafter comes from the bf16 source, not a quantized base.
• MTP acceptance on Qwen models is markedly better with thinking mode enabled.
• Q8_0 is the reference companion; Q4_K_L saves ~1 GiB at lower drafter precision.

Attribution and license

Source weights: Qwen/Qwen3.8-Flash-Next (Qwen team, Alibaba Cloud), Apache-2.0. These files repackage a subset of those weights and inherit that license. Pairs with unsloth/Qwen3.8-Flash-Next-GGUF or any other conversion. Extraction and encoding via mlx-kquant; the q4_k wire bytes are bit-identical to the reference GGUF codec.