Meta researchers taught an 8B AI model to match Claude Opus 4.5 — without the frontier price tag

Consider an AI agent tasked with a complex enterprise workflow like migrating massive batches of customer records from a legacy CRM to a cloud database. The agent cannot rely solely on its internal context window for a job spanning hours and depends on the runtime layer, aka the harness.This harness provides execution feedback, like server logs, to help the agent maintain an accurate understanding of dynamic API connections. It also provides state trackers and control-flow mechanisms to manage completed and pending subgoals, ensuring the agent doesn't skip or duplicate data batches. When unexpected errors occur, such as a database rejecting a batch due to strict API rate limits, the harness provides tools and instructions to help the agent recover.The main way to tell an agent how and when