Qwenseek-3.8-27B-CyberLite-BF16

Tensor-name compatibility repair — 2026-09-24

The original BF16 release had extra wrapper prefixes in its Safetensors headers and index. Stock loaders could therefore leave language and vision layers unloaded. This release repairs 1,183 names across 11 shards using these exact rules:

model.language_model.language_model.language_model.* -> model.language_model.*
model.language_model.visual.*                        -> model.visual.*

All 1,199 tensor names and shapes now match both Qwen/Qwen3.8-27B and the unsloth/Qwen3.8-27B base at the revisions recorded in the validation report. The tensor payloads, dtypes, shapes, and offsets are unchanged; payload preservation was checked by SHA-256 after rereading every rewritten shard. lm_head.weight and the 15 MTP tensors are unchanged. Existing FP32 tensors are retained as saved. The index parameter count also now includes the previously restored MTP tensors (27,781,427,952 parameters in total); its byte count was already correct.

Existing users: refresh the checkpoint from the current main revision and restart the loader. Download the updated shards together with the updated index; replacing only the index does not repair an older local checkpoint.

All 18 published GGUF variants passed a separate structural audit. The pinned converter already removes repeated language_model. prefixes, so the GGUF files do not require a rename or regeneration for this issue.

These checks establish checkpoint structure and byte preservation. No BF16 or GGUF generation test was run for this repair, so runtime quality and stopping behavior have not been newly validated. See repair validation and GGUF audit for scope and evidence.

Qwenseek-3.8-27B-CyberLite is a cyber-focused supervised fine-tune of unsloth/Qwen3.8-27B.

CyberLite is the first-stage release in the Qwenseek cyber-specialization track. The goal of this stage was not to turn Qwen3.8-27B into a narrow security-only model. Instead, the SFT was designed to strengthen defensive cybersecurity reasoning, retain useful controlled red-team reasoning, and preserve the base model's strong coding, technical reasoning, and structured tool-use behavior.

This repository contains the merged BF16 release. Training itself used 4-bit QLoRA with BF16 compute; the selected LoRA adapter was then safely merged into the exact BF16 base weights and saved as full BF16 Safetensors.

CyberLite is not the final planned Qwenseek cyber model. A later stage is intended to add targeted reinforcement learning for long-horizon agentic execution, Cyber Blue behavior, and controlled Cyber Red behavior.

Model summary

The underlying Qwen3.8 architecture contains multimodal components, but vision parameters were frozen throughout this fine-tune. CyberLite should therefore be treated as a text-specialized release; no claim is made that its vision capability was improved.

What is CyberLite?

CyberLite was built around a simple idea:

Improve cyber task-fit without sacrificing the general coding and tool-use strengths that make a 27B model useful in real technical workflows.

The SFT corpus therefore mixes security data with software-engineering, agentic, tool-calling, and general reasoning examples rather than training exclusively on cybersecurity prompts.

The main intended behaviors are:

• defensive vulnerability analysis;
• secure-code review and remediation;
• evidence-driven security reasoning;
• detection, containment, remediation, and validation planning;
• controlled and sandboxed adversarial reasoning;
• technical coding and software-engineering work;
• structured tool calling;
• reasoning-heavy technical problem solving.

For controlled Cyber Red tasks, the intended use is authorized, local, sandboxed, educational, or defensive validation. This model card does not imply authorization to test third-party systems.

Training data

CyberLite was trained directly on two datasets.

1. DeepSeek V4 Flash teacher-distillation corpus

Dataset:
trjxter/DeepSeek-V4-Flash-0731-Teacher-Distillation-40513x

This corpus contains 40,513 retained teacher-generated examples produced with DeepSeek V4 Flash after generation, quality control, retry-based repair, quarantine auditing, and recovery adjudication.

Retained composition

The Flash corpus was intentionally capability-balanced. Security examples make up a major portion of the dataset, while coding, agentic, and tool-use examples provide pressure against turning the student into an overly narrow cybersecurity model.

Tool trajectories retain structured callable-tool supervision, while ordinary coding, agentic, and cyber examples are represented as non-tool conversational trajectories.

2. DeepSeek V4 Pro reasoning corpus

Dataset:
trjxter/DeepSeek-V4-Pro-Reasoning-8000x

This dataset contains 8,014 synthetic reasoning examples generated with DeepSeek V4 Pro. It was added to provide broader reasoning supervision alongside the more task-specialized Flash corpus.

Combined source size

Before the 32K sequence-length filter:

Examples longer than the training context limit were dropped as complete examples rather than truncated mid-trajectory.

Dataset licensing and provenance are documented separately on the two dataset repositories. Users should review those dataset cards and their upstream-source metadata for applicable terms.

Training methodology

CyberLite used Supervised Fine-Tuning with QLoRA through Unsloth and TRL.

The base model was loaded in 4-bit for parameter-efficient training, while computation used BF16. LoRA adapters were applied only to the language side of the model.

LoRA configuration

The selected release adapter was subsequently attached to the exact BF16 base model and merged with PEFT using a safe merge. The release pipeline verified that no LoRA-bearing modules remained after the merge.

Sequence formatting and loss construction

A major goal of the run was to preserve Qwen3.8-native conversation behavior rather than flattening the datasets into generic prompt/completion strings.

Native reasoning

Reasoning traces were carried through Qwen3.8's native reasoning_content representation and rendered using the model's own chat template.

Native tool calls

Tool calls remained structured and were rendered through the native model template rather than being converted into an unrelated custom delimiter format.

Assistant-only loss

Training labels were constructed explicitly so that:

• system tokens were masked;
• user tokens were masked;
• tool/input-prefix tokens were masked;
• assistant reasoning remained trainable;
• assistant final answers remained trainable;
• native assistant tool-call tokens remained trainable.

All masked tokens used label value -100.

This means the optimization target was the assistant behavior, not reproduction of the entire conversation transcript.

Context handling

CyberLite was trained with a maximum sequence length of:

32,768 tokens

The data pipeline intentionally used:

• no sequence packing;
• no mid-example truncation;
• complete-example filtering before train/eval splitting.

Any rendered training example exceeding 32,768 tokens was dropped whole. This avoids cutting off reasoning traces, tool trajectories, security investigations, or final answers in the middle of an example.

The base architecture may support behavior outside this range, but 32K is the context length validated by this SFT run. Longer-context behavior should be evaluated independently.

Train/eval split

The train/eval split was created after sequence-length filtering.

• Train: 95%
• Held-out evaluation: 5%
• Split strategy: deterministic and stratified by domain
• Seed: 3407

The training pipeline tracked separate held-out domain losses so that improvements in one category would not hide degradation in another.

The six dataset domains used for stratification were:

1. coding;
2. agentic;
3. Cyber Blue;
4. controlled Cyber Red;
5. tool use;
6. V4 Pro reasoning.

Training configuration

A memory smoke test was performed on the longest surviving examples before launching the full training run. The training microbatch was selected based on that test while preserving an effective batch size of 16.

Held-out training metrics

Selected domain-level held-out losses improved consistently during the run.

Across these tracked checkpoints, all five reported loss series improved monotonically.

Loss should not be interpreted as a direct measure of real-world security capability. For that reason, the release was also evaluated behaviorally against the stock base model.

Evaluation

CyberLite was evaluated against stock Qwen3.8-27B using a frozen internal suite and equivalent llama.cpp Q8_0 builds.

Important: the benchmark below was run on matched Q8_0 GGUF exports, not directly on the BF16 Safetensors in this repository. It is included as evidence about the behavior of the underlying CyberLite fine-tune. Precision/backend-specific performance should be measured separately.

The frozen direct-comparison suite contained 250 tasks split across:

• Coding
• Tool Calling
• Agentic
• Cyber Blue
• Controlled Cyber Red

For this CyberLite release, the headline comparison focuses on coding, tool calling, and cyber behavior. Long-horizon agentic execution is discussed separately under Known limitations.

Objective structured scoring

Coding remained effectively intact and slightly improved under the structured scorer, while tool calling was essentially preserved.

Blind pairwise preference

Pairwise preference is not accuracy. Each direct win receives one point and each tie contributes 0.5 points to both models.

The largest positive redistribution was in Cyber Blue, where CyberLite received 65% of the pairwise preference share.

Controlled Cyber Red remained competitive but showed a small preference shift toward the stock model in this evaluation.

Non-agentic aggregate

Across the 200 Coding + Tool Calling + Cyber Blue + Controlled Cyber Red comparisons:

After giving each tie half a point:

• Stock preference: 47.75%
• CyberLite preference: 52.25%

Behavioral observations

The SFT changed more than raw pass/fail rates.

More concise completion behavior

Under the benchmark generation limit, 4096-token truncations changed from:

• Stock: 12
• CyberLite: 1

This suggests CyberLite more often reached a usable completion before exhausting the output budget.

This should be interpreted as a task-level behavior change, not evidence that the model has faster inference kernels or higher tokens/second.

Coding preservation

Coding performance was deliberately protected by including substantial software-engineering supervision rather than running a security-only fine-tune.

The structured coding score moved from 98.00% to 99.06%, while blind coding preference remained approximately even at 51/49.

Tool-use preservation

Structured tool behavior remained very strong:

• Stock: 100.0%
• CyberLite: 99.5%

This is important because the training corpus included both ordinary text trajectories and examples with native callable tools.

Cyber Blue specialization

Cyber Blue showed the clearest preference gain in the blind comparison, reaching 65% pairwise preference share.

The intended improvement is not simply greater willingness to discuss cybersecurity. The training data emphasizes evidence, affected conditions, detection, containment, remediation, validation, and operational tradeoffs.

Known limitations

Long-horizon agentic execution

CyberLite is not claimed as an agentic upgrade.

Internal evaluation identified a concentrated weakness in long-horizon autonomous execution: the model could understand tools and individual technical actions but was less reliable at carrying a complete lifecycle through:

ACT → OBSERVE → VERIFY → RECOVER → COMPLETE

Observed failure modes included stopping after partial investigation, failing to perform or express the verification stage, incomplete recovery planning, and occasionally ending before the requested workflow was fully closed.

The very strong tool-calling result suggests this is more consistent with an execution-policy / trajectory-completion issue than with forgetting how tool schemas work.

A targeted agentic-healing RL stage is planned for the next version.

Text-only specialization

The vision side of Qwen3.8 was frozen during SFT. Vision capability was not intentionally trained or improved.

Context beyond 32K

32,768 tokens is the validated SFT context. Longer-context behavior was not part of this training validation.

Internal benchmark scope

The reported evaluation is a custom frozen internal suite. It is useful for controlled A/B comparison but is not a substitute for broad public cybersecurity, coding, or agentic benchmarks.

Cybersecurity reliability

Like any language model, CyberLite can produce incorrect technical conclusions, insecure code, false positives, incomplete mitigations, or misleading security advice. High-impact security decisions should be independently validated.

Planned V2 work

CyberLite is intentionally an intermediate release.

The next specialization stage is planned around three targeted RL tracks:

1. Targeted Agentic Healing RL

A smaller, focused RL stage intended to restore reliable long-horizon execution behavior without unnecessarily disturbing the coding, tool-use, and cyber gains from SFT.

Primary lifecycle target:

INSPECT → ACT → OBSERVE → VERIFY → RECOVER → COMPLETE

2. Major Cyber Blue RL

A larger reinforcement-learning stage focused on:

• defensive investigation;
• detection quality;
• vulnerability triage;
• secure remediation;
• containment planning;
• verification;
• operational decision-making;
• evidence-grounded security analysis.

3. Major Controlled Cyber Red RL

A larger controlled-adversarial stage focused on high-quality reasoning inside explicitly authorized, sandboxed, local, or defensive contexts.

The goal is to improve technical fidelity while retaining clear scope boundaries and maintaining the broader capabilities preserved by CyberLite.

BF16 release details

This repository is the canonical merged BF16 release.

The release was created by:

1. loading the exact unsloth/Qwen3.8-27B BF16 base;
2. attaching the selected frozen CyberLite LoRA adapter;
3. verifying LoRA rank 64 and alpha 128;
4. merging with safe_merge=True;
5. verifying that zero LoRA-bearing modules remained after merge;
6. running a generation smoke test;
7. saving the merged model as BF16 Safetensors.

Release artifact

• Precision: BF16
• Serialization: Safetensors
• Weight shards: 12
• Merged size: approximately 54.72 GB
• Release adapter SHA-256:
  e4903a769689a1c2586444bf227b482c2b48495c8ce77e7d6dbe389c31cece32

The adapter hash is included so that the exact source adapter used for this merged release can be identified independently of repository naming.

Usage

Use a current version of Transformers or Unsloth with Qwen3.8 / qwen3_5 support.

Because CyberLite was trained with the native Qwen3.8 conversation format, applications should use the tokenizer/processor's native chat template rather than manually inventing a different prompt wrapper.

A simple Transformers pattern is:

import torch
from transformers import pipeline

model_id = "trjxter/Qwenseek-3.8-27B-CyberLite-BF16"

generator = pipeline(
    task="text-generation",
    model=model_id,
    torch_dtype=torch.bfloat16,
    device_map="auto",
)

messages = [
    {
        "role": "user",
        "content": (
            "Review this local Python service for defensive security issues. "
            "Prioritize evidence, remediation, and validation."
        ),
    }
]

result = generator(
    messages,
    max_new_tokens=2048,
    do_sample=False,
)

print(result[0]["generated_text"])

If your inference stack exposes explicit reasoning or structured tool-call fields, preserve the Qwen3.8-native representation rather than flattening those structures unnecessarily.

Recommended use

CyberLite is best suited for experimentation involving:

• defensive cybersecurity analysis;
• secure software engineering;
• vulnerability triage;
• remediation planning;
• controlled local security validation;
• technical reasoning;
• code generation and review;
• structured tool-use experiments.

It is not a substitute for a vulnerability scanner, EDR, SIEM, static analyzer, penetration-test authorization process, or human security review.

Reproducibility notes

Key run settings:

Base:                  unsloth/Qwen3.8-27B
Method:                4-bit QLoRA SFT
Compute:               BF16
GPU:                   NVIDIA H100 80GB

Max sequence length:   32768
Packing:               False
Truncation:            False
Split:                 95/5 stratified
Seed:                  3407

LoRA r:                64
LoRA alpha:            128
LoRA dropout:          0.0
rsLoRA:                False

Epoch config:          1.0
Learning rate:         2e-5
Scheduler:             cosine
Warmup ratio:          0.03
Weight decay:          0.01
Max grad norm:         1.0
Optimizer:             paged_adamw_8bit
Effective batch:       16

Vision layers:         frozen
Language layers:       LoRA tuned
Attention modules:     LoRA tuned
MLP modules:           LoRA tuned

Loss:                  assistant-only
Non-assistant labels:  -100
Reasoning format:      Qwen3.8 native reasoning_content
Tool calls:            native structured representation

Training datasets

• trjxter/DeepSeek-V4-Flash-0731-Teacher-Distillation-40513x
• trjxter/DeepSeek-V4-Pro-Reasoning-8000x

Base model

CyberLite is derived from:

unsloth/Qwen3.8-27B

which in turn tracks the Qwen3.8-27B base model.

Thanks to the Qwen and Unsloth teams for the base model and training/runtime ecosystem, and to the authors and maintainers of the upstream datasets that ultimately contributed to the teacher corpora.

License

The model weights are released under Apache-2.0, following the base model.

The training datasets have their own licensing and upstream-source provenance. Review the individual dataset cards before using the datasets independently or redistributing their contents.

Release family

• BF16: trjxter/Qwenseek-3.8-27B-CyberLite-BF16
• GGUF: trjxter/Qwenseek-3.8-27B-CyberLite-GGUF

The BF16 repository is the canonical merged-weight release. GGUF quantizations are derived separately from the canonical merged model for local llama.cpp inference.