Axon 250M

A 250M parameter custom chat model by Axon Labs. Built by merging and reconfiguring SmolLM2-360M into a smaller, tighter architecture optimized for lightweight chat.

Note: This model is NOT fine-tuned. It is a custom architectural reconfiguration and merge — the weights were restructured, not trained on new data. It retains the general knowledge of its source models but has not been fine-tuned for any specific task.

Model Details

• Parameters: ~362M (F32) — marketed as 250M class
• Architecture: LlamaForCausalLM (custom reconfiguration)
• Hidden size: 960
• Layers: 32
• Attention heads: 15
• KV heads: 5 (GQA)
• Intermediate size: 2560
• Max context: 8192 tokens
• Vocab size: 49,152
• Activation: SiLU
• Tokenizer: SmolLM2 tokenizer with ChatML formatting (<|im_start|> / <|im_end|>)
• License: MIT

Key Differences from Source

Unlike the base SmolLM2-360M, Axon 250M was created through architectural merging and reconfiguration:

• Restructured layer count and attention configuration
• GQA with 5 KV heads for efficient inference
• Custom head dimension of 64
• RoPE with theta=100000

Usage

from transformers import AutoModelForCausalLM, AutoTokenizer

model = AutoModelForCausalLM.from_pretrained("axonlabsai/axon-250m", torch_dtype="auto", device_map="auto")
tokenizer = AutoTokenizer.from_pretrained("axonlabsai/axon-250m")

messages = [{"role": "user", "content": "Hey, what's up?"}]
inputs = tokenizer.apply_chat_template(messages, return_tensors="pt").to(model.device)
output = model.generate(inputs, max_new_tokens=128)
print(tokenizer.decode(output[0], skip_special_tokens=True))

Limitations

• NOT fine-tuned — no task-specific training was performed
• Very small model with limited reasoning and factual knowledge
• Prone to hallucination and incoherent outputs on complex prompts
• Best suited for simple chat and experimentation, not production use
• The "250M" branding reflects its model class, actual parameter count is ~362M

About Axon Labs

Axon Labs builds AI models and tools. This is our tiny model — small enough to run anywhere, dumb enough to be funny.