Meta's EvoHarness-RL: Agents Learn to Autonomously Manage External Frameworks

omarsar0 · x · 2026-08-10

Meta has published new research on AI agents titled EvoHarness-RL. Current agent harnesses are mostly hand-authored, making it difficult to tune robust behaviors for long-horizon tasks.

The proposed method allows agents to learn harness policies offline and dynamically construct or update external states online during runtime. Specifically, the model learns the action space via supervised harness fine-tuning, followed by cost-aware GRPO to explore when to read, update, and consolidate during long-running tasks. Experiments show that Qwen3-8B achieves a 96.9% success rate on the ALFWorld benchmark.

Two key dynamics emerge from the training process:

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