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Swift 1.5 GLM-5.3-Flash

GGUF quantizations. Derived directly from Swift 1.5 GLM-5.3-Flash with llama.cpp. Run a chosen quantization tier with a current llama.cpp-compatible runtime such as llama-server.

Swift 1.5 GLM-5.3-Flash is UkisAI's reasoning-efficient derivative of GLM-5.3-Flash. It uses 57.7% fewer thinking tokens, with a 2.4x speed up while keeping the accuracy loss <1% vs base on max reasoning effort.

The prompt is a sample from LiveCodeBench v6

Training approach

We made Swift GLM-5.3-Flash efficient by figuring out which tokens were linked to pathological overthinking and penalizing them without "attacking" the reasoning length directly, then regained the accuracy with further post-training, leading to "compressed" token usage while maintaining accuracy.

Swift 1.5 produces shorter reasoning traces. In our testing, we also observe fewer overthinking errors.

This release also features our previously mentioned post-training methods adapted specifically for coding and long-horizon agent work such as terminal use and software engineering.

Our training data is viewable here: https://huggingface.co/datasets/ukisai/Qwen3.8-27B-multi-turn-agent-sft albeit it is not used out of the box, but rather re-sampled, turned into proper RL environments etc.

Evaluation

The external results below compare GLM-5.3-Flash, the foundation base model, and Swift 1.5. Both models use the same saved evaluation protocols, and all scores are reported as final aggregate percentages.

Benchmark Score Mean tokens Median tokens
BaseSwift 1.5 BaseSwift 1.5 ReductionReduction
General reasoning
GPQA-Diamond90.51%89.90%10,2486,052↓ 40.9%↓ 57.7%
MMLU-Pro87.38%86.25%2,7551,064↓ 61.4%↓ 44.4%
C-Eval93.42%93.68%1,214752↓ 38.0%↓ 19.9%
IFBench56.40%55.73%11,6608,299↓ 28.8%↓ 22.9%
Mathematics
AIME 202693.33%92.67%24,19318,145↓ 25.0%↓ 45.8%
HMMT (Nov 2025)95.33%91.33%25,92418,797↓ 27.5%↓ 31.7%
Coding
LiveCodeBench v686.69%87.94%21,50614,645↓ 31.9%↓ 36.1%
Agentic coding
Terminal-Bench 2.1*76.40%75.96%118,87879,473↓ 33.1%↓ 36.8%
DeepSWE v1.146.02%48.67%75,67159,513↓ 21.4%↓ 20.9%

* Note: Terminal-Bench 2.1 ran with a 5-hour limit (18,000 seconds) on every task, not the native per-task limits, for both base and Swift 1.5.

How to reproduce

Serving: BF16 · vLLM · GLM-4.7 reasoning parser · context 262,144 · reasoning effort max · MTP disabled.
Sampling: temperature 1.0 · top_p 0.95 · presence_penalty 0 · repetition_penalty 1.
Benchmarks: five seeds (0–4) for the question benchmarks. LiveCodeBench is full release v6 mean pass@1 over seeds.
Terminal-Bench 2.1: Harbor 0.20.0 / Terminus-2, pinned 89-task dataset, five attempts per task, temperature 1, top_p 1, 18,000-second task limit.
DeepSWE v1.1: 113 tasks × 3 attempts, Pier 0.3.1 with mini-swe-agent 2.4.6, GLM-4.7 tool-call parser.

BenchmarkOutput cap
GPQA-Diamond100,000
MMLU-Pro100,000
C-Eval16,384
IFBench81,920
AIME 2026250,000
HMMT Nov 2025250,000
LiveCodeBench v6100,000

Efficiency across reasoning efforts

GPQA-Diamond at each reasoning_effort setting, Swift 1.5 against the base at the same setting:

Reasoning effort Score Mean tokens Median tokens
BaseSwift 1.5 BaseSwift 1.5 ReductionReduction
Max90.51%89.90%10,2486,052↓ 40.9%↓ 57.7%
High88.79%86.97%7,6234,158↓ 45.5%↓ 31.1%
Low77.27%73.33%2,8151,377↓ 51.1%↓ 13.7%

At max, Swift 1.5 trails base by 0.61 percentage points while using 40.9% fewer mean and 57.7% fewer median thinking tokens. High and low save tokens but also lose 1.82 and 3.94 percentage points respectively.

Quantized models

Format Repository Runtime
NVFP4 Swift-1.5-GLM-5.3-Flash-NVFP4 NVIDIA Blackwell
AWQ INT4 (W4A16) Swift-1.5-GLM-5.3-Flash-W4A16-AWQ vLLM (compressed-tensors)
GGUF Swift-1.5-GLM-5.3-Flash-GGUF llama.cpp

Each quantized Swift 1.5 against a quantized base of the same format, on the same protocol as the BF16 evaluation:

Benchmark Score Mean tokens Median tokens
BaseSwift 1.5 BaseSwift 1.5 ReductionReduction
NVFP4
GPQA-Diamond90.10%90.20%13,0697,148↓ 45.3%↓ 59.5%
AIME 202694.00%91.33%30,85529,768↓ 3.5%↓ 48.3%
W4A16-AWQ
GPQA-Diamond90.81%89.19%10,6016,718↓ 36.6%↓ 55.3%
AIME 202692.67%94.00%20,13822,546↑ 12.0%↓ 46.8%

NVFP4 base: nvidia/GLM-5.3-Flash-NVFP4, the same recipe. W4A16-AWQ base: wtdcode/GLM-5.3-Flash-AWQ-W4A16, the closest public AWQ.

GGUF quantizations

File Size KLD wikitext @512 KLD wikitext @32k 99% KLD @32k Top-p @32k
Q8_0341.5 GB0.01790.00730.09697.06%
Q6_K281.0 GB0.01920.00920.12496.69%
Q6_K_S268.2 GB0.02160.00920.12296.75%
Q5_K_M243.7 GB0.03120.01550.21296.16%
Q5_1 †240.5 GB0.04280.02410.30594.45%
Q5_K_S227.9 GB0.03300.01750.23595.76%
Q5_0 †221.4 GB0.04770.02590.35994.42%
Q4_1202.6 GB0.08170.04720.56992.47%
Q4_K_M200.8 GB0.05620.03160.41494.29%
IQ4_NL200.8 GB0.06170.03660.46093.85%
Q4_K_S189.3 GB0.06730.03590.46393.79%
Q4_0184.1 GB0.09710.06940.83191.30%
IQ4_XS177.7 GB0.07110.04090.52493.60%
MXFP4_MOE †176.1 GB0.13150.08341.15190.70%
IQ3_M166.6 GB0.13260.09521.25389.76%
Q3_K_L162.4 GB0.12730.08151.09990.49%
Q3_K_M155.0 GB0.15000.09481.23489.98%
Q3_K_S147.4 GB0.16440.10141.21889.47%
IQ3_XS147.4 GB0.17280.14121.85187.82%
IQ3_S †140.9 GB0.22450.19472.19285.18%
IQ3_XXS138.8 GB0.21820.16332.05486.67%
Q2_K125.7 GB0.39800.28123.09281.98%
IQ2_M120.6 GB0.35680.27333.14282.76%
Q2_K_S †110.4 GB0.66140.49924.72075.51%
IQ2_S107.5 GB0.47560.47835.15977.71%
IQ2_XS101.4 GB0.51930.54015.29475.84%
IQ2_XXS96.6 GB0.59110.45564.59876.82%
IQ1_M83.0 GB0.88680.72916.30370.18%
IQ1_S74.8 GB1.02201.04247.78264.40%

Mean KL divergence against the Swift 1.5 BF16 source, lower is better. wikitext @512 is wikitext-2 test, 100 windows of 512 tokens. wikitext @32k is wikitext-2 train, 16 windows of 32,768 tokens, scoring the last 512 tokens of each window, so every scored token sees at least 32k tokens of context. 99% KLD is the 99th-percentile divergence on the same 32k run. Top-p is top-token agreement with BF16 on the 32k run. † = llama.cpp's own mix.

Each tier is in its own folder, split into several parts. llama.cpp loads every part from the first one. The vision encoder is in the separate mmproj file:

llama-server -hf ukisai/Swift-1.5-GLM-5.3-Flash-GGUF:Q4_K_M --jinja
# or, after downloading a folder and the mmproj file:
llama-server -m Q4_K_M/Swift-1.5-GLM-5.3-Flash-Q4_K_M-00001-of-00005.gguf \
  --mmproj mmproj-Swift-1.5-GLM-5.3-Flash-BF16.gguf --jinja
Use case Pick
Maximum fidelityQ8_0
Long agentic runs, strict tool-call formattingQ6_K or Q6_K_S
Everyday use, about 200 GB of GPU plus system memoryQ4_K_M
About 180 GBIQ4_XS
About 160 GBQ3_K_L
Recipe

All 29 tiers were built with llama.cpp commit 2a66703 from a BF16 conversion of the published Swift 1.5 safetensors. They use the importance matrix and per-tensor type layouts from bartowski/GLM-5.3-Flash-BF16-GGUF; the † tiers use llama.cpp's own mix. Every file was checked against BF16 on the harness above.

License and access

Swift 1.5 GLM-5.3-Flash is a derivative of GLM-5.3-Flash (Copyright (c) 2026 Z.AI Co., Ltd, MIT License). UkisAI's contribution, including the adapted weights, is licensed under the Swift Open License v1.0. See NOTICE for the change notice and attribution details.

Personal, research, educational, evaluation, and commercial use of the Swift contribution are free for individuals and organizations with gross annual revenue, including affiliates, of up to US$1,000,000. Above that threshold, commercial use requires a separate Swift Enterprise License. Contact UkisAI for terms.

The base model's MIT License still applies to the base model. Nothing in the Swift Open License limits your rights in GLM-5.3-Flash itself under the MIT License.

Citation

@misc{swift-1.5-glm-5.3-flash,
  title  = {Swift 1.5 GLM-5.3-Flash},
  author = {UkisAI},
  year   = {2026},
  url    = {https://huggingface.co/ukisai/Swift1.5-GLM-5.3-Flash}
}

Acknowledgements

We acknowledge Amazon Web Services for providing compute credits and infrastructure support for Swift's development, training, and evaluation.

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