ctokx/regexgym-qwen3-4b

TEXT GENERATIONPricing:Input $0.4 / Cached $0.08 / Output $0.8Concurrent Unit Cost:1Model Size:4BQuant:BF16Context Size:32kTool Calling:SupportedPublished:Aug 7, 2026License:otherArchitecture:Transformer Featherless Exclusive Cold

The ctokx/regexgym-qwen3-4b is a 4 billion parameter Qwen3-based causal language model fine-tuned by ctokx. This model specializes in generating regular expressions from positive and negative examples, demonstrating a 44% pass@1 score on unseen tasks. It was trained on the regexgym-verified-traces dataset, focusing on producing accurate regexes that separate matching and non-matching strings. Its primary strength lies in its ability to induce precise regular expressions, outperforming its base model and classical induction methods.

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RegexGym-Qwen3-4B: Regular Expression Induction Model

This model, ctokx/regexgym-qwen3-4b, is a 4 billion parameter Qwen3-based language model specifically fine-tuned by ctokx for generating regular expressions. Its core capability is to infer a single regex that correctly matches all provided positive examples and rejects all negative examples.

Key Capabilities & Performance

  • Regex Induction: Generates regular expressions from user-provided positive and negative string examples.
  • Performance: Achieves a 44% pass@1 on 120 held-out, decontaminated tasks, meaning it produces a fully correct regex for 44% of unseen problems. This is a significant improvement over the base Qwen3-4B (37% pass@1) and classical regex induction methods (10% pass@1).
  • High Hidden Accuracy: Demonstrates a mean hidden accuracy of 0.82, indicating that even when not perfectly correct, its generated regexes are usually very close to the optimal solution.
  • Training Methodology: Fine-tuned over three epochs on the regexgym-verified-traces dataset, which consists of teacher reasoning traces generated by Gemma-4-31B and verified by execution against hidden holdouts.

When to Use This Model

  • Automated Regex Generation: Ideal for applications requiring the programmatic creation of regular expressions based on example data.
  • Data Cleaning & Validation: Useful for quickly generating patterns to identify or filter specific string formats.
  • Educational Tools: Can serve as a component in tools designed to teach or assist with regular expression construction.

While it doesn't fully match the performance of its 8x larger teacher model (Gemma-4-31B), this 4B parameter model offers a highly efficient and specialized solution for regex induction tasks.