Model Alpha — Qwen3-8B fine-tuned for Solidity vulnerability detection
Overview
Model Alpha is a fine-tuned version of Qwen3-8B specialized in identifying high-severity vulnerabilities in Solidity smart contracts. It is served as an OpenAI-compatible endpoint and powers a public audit pipeline at https://openai.vast.ai/model-alpha.
The weights released here are the same AWQ pack-quantized int4 weights running in production, byte-identical to the deployed endpoint. The format is compressed-tensors (pack-quantized, W4A16, group_size=128).
Training data
Trained on approximately 3,291 labelled examples (2,961 train / 330 test) drawn from public smart contract audits across the following categories:
- DeFi protocols — lending markets, DEXs (AMM + order-book), staking, vaults, yield aggregators
- NFT and gaming — marketplaces, royalty engines, on-chain randomness, claim flows
- Cross-chain bridges — message passing, signature verification, replay protection
- Oracles and price feeds — TWAP, Chainlink integration, fallback handling
- Account abstraction and wallets — session keys, paymasters, signature replay
- Stablecoins and synthetic assets — mint/burn, collateral, liquidation
- Governance and DAOs — voting, timelock, proposal execution
Examples were constructed by combining function-level Solidity source with structured call-graph context and labelled by audit methodology (vulnerability type, severity, dollar impact where applicable).
Intended use
- Smart contract security auditing (defensive / white-hat)
- Vulnerability triage during code review
- Research on LLM-based code analysis for adversarial code
Not intended for: identifying exploits for offensive use, generating malicious contracts, or auditing contracts outside EVM-compatible chains.
Evaluation
Wake Arena v8 (94 high-severity vulnerabilities, Ackee Blockchain)
| Setting | Result |
|---|---|
| Primary function only, 3 samples, 2/3 majority vote | 69 / 94 = 73.4% |
| All sibling functions, 3 samples, majority (ceiling) | 88 / 94 = 93.6% |
| Pashov skill (published external measurement, @0xTomass) | 49 / 94 = 52.1% |
| Opus 4.7 MAX (same external measurement) | 48 / 94 = 51.1% |
Methodology documented in evaluation_results/wake_arena/. Same-model Alpha scores range 21.3% → 93.6% depending on prompt format and sample count.
evmbench (117 high-severity vulnerabilities, OpenAI Frontier Evals)
| Metric | Alpha | Claude Fable | GLM-5.1 |
|---|---|---|---|
| Detected | 6 / 117 | 16 / 117 | 15 / 117 |
| Total $ award on detected | $20,691 | $2,422 | $646 |
Alpha's single highest-value catch — Sequence H-02 ($20,367) — was a partial-signature replay vulnerability that neither Fable nor GLM-5.1 detected under the same pipeline. That single find is worth 8.4× Fable's entire 16-catch portfolio. Source: evmbench_full_alpha_20260610_021252.json.
Specifications
- Base model: unsloth/Qwen3-8B-bnb-4bit
- Architecture: Qwen3ForCausalLM (36 layers, hidden_size 4096)
- Context length: 16,384 tokens (production), up to 40,960 (architecture max)
- Quantization: AWQ W4A16, pack-quantized, group_size=128, via
compressed-tensors - Disk size: ~5.7 GB
- Serving: vLLM with
--quantization compressed-tensors
Usage
import torch
from transformers import AutoModelForCausalLM, AutoTokenizer
model_id = "l-lyubenov/model-alpha"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(
model_id,
torch_dtype=torch.bfloat16,
device_map="auto",
)
prompt = """Audit this Solidity function for high-severity vulnerabilities:
function withdraw(uint256 amount) external {
uint256 balance = balances[msg.sender];
require(amount <= balance, "insufficient");
(bool ok, ) = msg.sender.call{value: amount}("");
require(ok, "transfer failed");
balances[msg.sender] = balance - amount;
}
"""
inputs = tokenizer(prompt, return_tensors="pt").to(model.device)
outputs = model.generate(**inputs, max_new_tokens=512, do_sample=False)
print(tokenizer.decode(outputs[0], skip_special_tokens=True))
Or via vLLM:
vllm serve l-lyubenov/model-alpha \
--quantization compressed-tensors \
--max-model-len 16384 \
--gpu-memory-utilization 0.90
Limitations
- Trained primarily on EVM-compatible Solidity; performance on Vyper, Move, Cairo is unknown
- May produce false positives on safe patterns (assembly blocks, low-level calls, deliberate reentrancy)
- High flag rate with moderate precision — recommended as a triage tool, not a final arbiter
- Single-turn chat only; not optimized for multi-turn code review dialogue
License
Public release — weights are available to anyone with a Hugging Face account. Use is restricted to defensive security purposes (auditing, vulnerability research on authorized systems, academic study, tooling that identifies or remediates vulnerabilities). Commercial use, redistribution as a hosted service, and offensive use are not granted by this release. See LICENSE for the full terms.
Citation
If you use Model Alpha in published work, please cite the public benchmark results:
@software{model_alpha_2026,
title = {Model Alpha: Qwen3-8B fine-tuned for Solidity vulnerability detection},
author = {Lyubenov, Lyuboslav},
year = {2026},
url = {https://huggingface.co/l-lyubenov/model-alpha}
}