It all starts with ๐ฅ๐ฒ๐ถ๐ป๐ณ๐ผ๐ฟ๐ฐ๐ฒ๐บ๐ฒ๐ป๐ ๐๐ฒ๐ฎ๐ฟ๐ป๐ถ๐ป๐ด ๐๐ถ๐๐ต ๐ฉ๐ฒ๐ฟ๐ถ๐ณ๐ถ๐ฎ๐ฏ๐น๐ฒ ๐ฅ๐ฒ๐๐ฎ๐ฟ๐ฑ๐ - question asked - model generates reasoning + answer - answer checked against ground truth - reward drives RL training
In this setup, the environment is simple: fixed questions and answers, rollout logic, reward(s)
Consider a more complex tic-tac-toe env โโญ It adds: - dynamic game generation/handling - tunable opponent skill - multi-turn interactions
(envs can also include tools)
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What happens at training?
We use ๐๐ฟ๐ผ๐๐ฝ ๐ฅ๐ฒ๐น๐ฎ๐๐ถ๐๐ฒ ๐ฃ๐ผ๐น๐ถ๐ฐ๐ ๐ข๐ฝ๐๐ถ๐บ๐ถ๐๐ฎ๐๐ถ๐ผ๐ป with a tic-tac-toe env
No critic model needed, the group is the baseline Simpler than PPO
1๏ธโฃ Rollout generation: from the same board, model plays N games via sampling 2๏ธโฃ Each game scored with deterministic rewards (win, format, ...) 3๏ธโฃ Mean score computed across the group 4๏ธโฃ Each rollout's advantage = its score minus the group mean 5๏ธโฃ Model updated to favor trajectories above baseline
We annotated 119K medical images with two frontier VLMs (Qwen 3.5, Kimi K2.5), cross-validated at 93% agreement, and produced 110K training records, all for under $500. Fine-tuning 3 small models (2-3B params) improved all benchmarks: best model reaches +15.0% average exact match.
Everything is open-sourced: datasets, adapters, and code.