Mechanism
Designed specifically for long-horizon asynchronous agentic RL where group-wise sampling ( or rollouts per prompt) creates severe tail-latency stragglers and off-policy staleness. SAO uses:
- Single-Rollout Sampling (): Generates only 1 rollout per prompt so rollouts stream immediately into the training buffer as soon as they finish.
- Stabilized Value-Model Critic: Uses a learned value model to provide baseline & advantage estimates for single rollouts without group variance.
- Strict Double-Sided Token-Level Clipping: Enforces tight symmetric/asymmetric token-ratio bounds and rejects stale off-policy tokens to maintain stability over 1,000+ asynchronous RL steps.
In Ulam's V-SAO (Verified Reasoning SAO), SAO is paired with shaped proof-verification rewards after specialized research SFT (
A-SFT).
Practical Notes
Solves the fundamental bottleneck of synchronous GRPO in long-horizon SWE, terminal, and open-problem math research environments.