agurung/cobalt-seeded-rl-base-ramp25-stoppen-gen4k-ep2-ncp5-q4v3-groot16

TEXT GENERATIONPricing:Input $0.4 / Cached $0.08 / Output $0.8Concurrent Unit Cost:1Model Size:4BQuant:BF16Context Size:32kTool Calling:SupportedPublished:Sep 18, 2026Architecture:Transformer Featherless Exclusive Cold

The agurung/cobalt-seeded-rl-base-ramp25-stoppen-gen4k-ep2-ncp5-q4v3-groot16 is a 4 billion parameter OpenRLHF GRPO reinforcement-learning checkpoint based on Qwen3-4B-Instruct-2507, with a context length of 32768 tokens. This model is specifically fine-tuned for code generation, utilizing a binary code-correctness reward signal. It excels at solving programming problems, demonstrating strong performance on the cobalt-train frontier with a pass@8 score of 1.8061.

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Overview

This model, agurung/cobalt-seeded-rl-base-ramp25-stoppen-gen4k-ep2-ncp5-q4v3-groot16, is a 4 billion parameter OpenRLHF GRPO reinforcement-learning checkpoint derived from the Qwen/Qwen3-4B-Instruct-2507 base model. It was developed by agurung and represents the best performing checkpoint (by pass@8) from its training run, saved at global step 24.

Key Capabilities

  • Code Generation: Specifically optimized for generating correct code, trained with a binary code-correctness reward signal.
  • Problem Solving: Demonstrates strong performance on programming challenges, validated against the cobalt-train frontier.
  • Reinforcement Learning: Utilizes the GRPO algorithm with specific penalties for truncated and overlong responses to improve output quality.

Performance Metrics

Evaluated on a held-out validation set with 8 samples per problem, this checkpoint achieved:

  • pass@1: 0.2794 (unbiased mean per-problem fraction correct)
  • pass@8: 1.8061 (problem counted solved if any sample is correct)

Good for

  • Automated Code Generation: Ideal for tasks requiring the model to produce functional code that passes tests.
  • Competitive Programming Assistance: Can be used to generate solutions for programming problems, particularly those on the cobalt-train frontier.
  • Research in RL for Code: Provides a strong baseline for further research into reinforcement learning applications for code generation.