Pluto-AI-Labs/Atlas-Coder-0.5B

TEXT GENERATIONPricing:Input $0.04 / Cached $0.008 / Output $0.08Concurrent Unit Cost:1Model Size:0.5BQuant:BF16Context Size:32kTool Calling:SupportedPublished:Jul 17, 2026License:apache-2.0Architecture:Transformer0.0K Open Weights Featherless Exclusive Cold

Atlas-Coder-0.5B by Siddharth N.R. is a 494 million parameter coding-specialized language model, instruction-tuned from scratch on Qwen2.5-Coder-0.5B base. Trained with QLoRA on 80K decontaminated code instructions, it focuses on efficient fine-tuning for sub-1B models on consumer hardware. This model excels at code generation and understanding, particularly for Python, with a context length of 32768 tokens.

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Atlas-Coder-0.5B: A Sub-1B Coding Specialist

Atlas-Coder-0.5B is a 494 million parameter language model developed by Siddharth N.R. as part of the Pluto AI research project. It is instruction-tuned from the Qwen2.5-Coder-0.5B base model using QLoRA on a Tesla T4 GPU, demonstrating that disciplined data curation can achieve near-instruct-level coding performance in a sub-500M model without proprietary alignment pipelines.

Key Capabilities & Features

  • Coding Specialization: Instruction-tuned specifically for code generation and understanding.
  • Efficient Training: Developed with a focus on efficient fine-tuning on consumer-grade hardware.
  • Curated Training Data: Trained on 80,000 decontaminated code instructions, including synthetic complexity, execution-verified open-source code, real-world debugging scenarios, and algorithmic reasoning datasets.
  • Decontamination: All training data was scanned against HumanEval to prevent memorization and ensure genuine generalization.
  • Optimized Training Techniques: Utilizes response-only loss masking, unfrozen embeddings and output head, and FP32 LoRA casting for improved performance from a base model.
  • Low Resource Inference: GGUF quantizations are available for efficient CPU inference with tools like Ollama, LM Studio, or llama.cpp.

Use Cases & Limitations

Atlas-Coder-0.5B is good for:

  • Generating Python functions and solving coding problems.
  • Debugging assistance and understanding code snippets.
  • Research into efficient fine-tuning of small language models for specialized tasks.

Limitations:

  • Due to its size (~494M parameters), it may struggle with complex, multi-file engineering tasks.
  • Optimized primarily for Python; performance on other languages may vary.
  • Trained on sequences up to 1024 tokens; performance may degrade with longer contexts.
  • Lacks real-time information and is not intended for production deployment without further evaluation.