When Tokens Become Actions: A Policy Gradient Built for Transformers
Opening — Why this matters now Reinforcement learning has always assumed that actions are atomic. Large language models politely disagree. In modern LLM training, an “action” is rarely a single move. It is a sequence of tokens, often structured, sometimes tool‑augmented, occasionally self‑reflective. Yet most policy‑gradient methods still pretend that Transformers behave like generic RL agents. The result is a growing mismatch between theory and practice—especially visible in agentic reasoning, tool use, and long‑horizon tasks. ...