Aletheia-Bench/GRPO-Instruct-1.5B

Hugging Face
TEXT GENERATIONPricing:Input $0.04 / Cached $0.008 / Output $0.08Concurrent Unit Cost:1Model Size:1.5BQuant:BF16Context Size:32kTool Calling:SupportedPublished:Nov 27, 2025License:cc-by-nc-sa-4.0Architecture:Transformer Open Weights Featherless Exclusive Warm

Aletheia-Bench/GRPO-Instruct-1.5B is a 1.5 billion parameter instruction-tuned code verifier developed by Aletheia-Bench, fine-tuned from Qwen2.5-1.5B-Instruct. This model is trained using Reinforcement Learning with Verifiable Rewards (RLVR) without intermediate thinking traces, directly emitting a verdict. It excels at judging and ranking candidate solutions for competitive programming problems, serving as a plug-and-play reward function for code generation policy optimization and automated evaluation.

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Model Overview

Aletheia-Bench/GRPO-Instruct-1.5B is a 1.5 billion parameter instruction-tuned code verifier, fine-tuned from Qwen/Qwen2.5-1.5B-Instruct. It is part of the Aletheia project, which explores the effectiveness of various RLVR (Reinforcement Learning with Verifiable Rewards) training recipes for code verifiers. This specific model is a GRPO-Instruct verifier, meaning it was trained with on-policy learning and negative samples but without intermediate thinking traces, directly providing a verdict on code solutions.

Key Capabilities

  • Code Verification: Judges and ranks candidate solutions for competitive programming problems, identifying the correct one among several options.
  • RLVR Training: Utilizes Reinforcement Learning with Verifiable Rewards, specifically the GRPO-Instruct approach, which is optimized for efficiency by omitting intermediate thinking traces.
  • Scalability Insights: Part of a research effort to understand how different RLVR components (thinking traces, negative samples, on-policy training) impact performance across various model scales.

Good For

  • RLHF / RLAIF: Can be used as a plug-and-play reward function to optimize code generation policies.
  • Automated Evaluation: Suitable for LLM-as-a-judge applications in various code-related tasks.
  • Research: Ideal for studying the impact of different training methodologies on code verifier performance, particularly the trade-offs between training cost and accuracy.