qwen3.5-0.8b-mermaid-generator

Qwen3.5-0.8B Mermaid Diagram Generator

A fine-tuned version of Qwen3.5-0.8B specialized for generating valid Mermaid 11.14 diagrams from natural language descriptions.

Model Details

• Base Model: Qwen/Qwen3.5-0.8B (0.8B parameters)
• Training Method: LoRA fine-tuning with Unsloth
• Dataset: SpongeBOB9684/mermaid-text-to-diagram
• Context Length: 32,768 tokens
• Training Examples: 9,913 validated Mermaid 11.14 examples

Usage

Installation

pip install transformers torch

Inference

from transformers import AutoModelForCausalLM, AutoTokenizer

model_name = "SpongeBOB9684/qwen3.5-0.8b-mermaid-generator"

tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForCausalLM.from_pretrained(model_name)

prompt = "Create a flowchart for a simple login process"
messages = [
    {"role": "system", "content": "You are a Mermaid diagram code generator. Output ONLY valid Mermaid code."},
    {"role": "user", "content": prompt},
]

text = tokenizer.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
inputs = tokenizer(text, return_tensors="pt")

outputs = model.generate(**inputs, max_new_tokens=256, temperature=0.7, top_p=0.8)
response = tokenizer.decode(outputs[0][inputs["input_ids"].shape[1]:], skip_special_tokens=True)

print(response)

Supported Diagram Types

The model is trained to generate:

• Flowcharts (flowchart)
• Sequence diagrams (sequenceDiagram)
• Class diagrams (classDiagram)
• State diagrams (stateDiagram-v2)
• ER diagrams (erDiagram)
• Gantt charts (gantt)
• Mind maps (mindmap)
• Pie charts (pie)
• Git graphs (gitGraph)

Model Capabilities

• Syntax Validation: All training examples validated with mermaid-cli
• Mermaid 11.14: Full support for latest syntax features
• Complexity: Handles simple to very complex diagrams (>25 nodes)
• Features: Subgraphs, styling, multi-directional arrows, markdown in nodes

Training Details

Dataset

This model was trained on a dataset of 9,913 validated examples sourced from three repositories:

Source Distribution:

• Celiadraw/text-to-mermaid (8,912 examples, ~90%): Existing data

  • https://huggingface.co/datasets/Celiadraw/text-to-mermaid
  • Non-LLM generated

• djds4rce/mermaid-synthetic (926 examples, ~9%): Existing data

  • https://huggingface.co/datasets/djds4rce/mermaid-synthetic
  • MIT License
  • Non-LLM generated

• Edge cases (75 examples, ~1%): LLM generated for Mermaid 11.14 coverage

  • Created to cover missing Mermaid 11.14 features
  • Strictly validated syntactically before inclusion

Splits:

• Train: 80% of examples
• Validation: 10% of examples
• Test: 10% of examples

Diagram Distribution:

• 54.7% flowcharts, 15.1% sequence, 10.4% class, etc.

Training Configuration

• Framework: Unsloth (2x faster, 70% less VRAM)
• Method: LoRA (0.1% trainable parameters)
• Precision: FP16
• Hardware: Trained on local GPU

Methodology

Validation

All training examples were validated using mermaid-cli (@mermaid-js/mermaid-cli) to ensure:

• ✅ Correct Mermaid 11.14 syntax
• ✅ Successful rendering
• ✅ Conformity with official specifications

Data Sources

Existing Data (~99% of dataset)

• Sourced from Celiadraw and djds4rce
• Used as-is, no LLM modifications
• Upgraded to Mermaid 11.14 where needed

LLM Generated Edge Cases (~1% of dataset)

• Generated specifically to cover missing Mermaid 11.14 features
• Validated with same rigor as existing data
• Covers edge cases and complex scenarios

Model Architecture

• Layers: 24
• Hidden Size: 2048
• Attention Heads: 16
• Vocabulary: 151,936 tokens

Documentation

This model is trained to generate code conforming to Mermaid 11.14.0:

• 📖 Documentation: https://mermaid.js.org/intro/
• 🔧 Syntax: https://mermaid.js.org/syntax/
• ✅ All training examples validated against official specs

Limitations

• Model may occasionally generate diagrams that require minor syntax adjustments
• Best results with clear, specific prompts
• Limited to Mermaid syntax (not general diagram description)

Browser Deployment

This model is designed for in-browser inference via Transformers.js and WebGPU, enabling client-side Mermaid generation without server API calls.

License

Apache 2.0

Acknowledgments

• Base model: Qwen3.5-0.8B by Alibaba Cloud
• Training framework: Unsloth
• Dataset sources:
  • Celiadraw/text-to-mermaid (existing data)
  • djds4rce/mermaid-synthetic (existing data, MIT License)
  • Edge cases generated by Mermaid Studio project