2AM separates memory from motor execution in long-horizon manipulation. A multimodal agent keeps all task history and, each step, steers a stateless RGB-based action model with subtask language plus optional 2D grasp, place, and move hints, rather than using depth, online geometry, or a planner. The action model was trained on demonstrations augmented with hint labels, then regularized with hint dropout, spatial noise, and temporal jitter so it can follow imperfect agent outputs. On LIBERO-Mem, 2AM reached 76.3% average completion against a 14.8% baseline, with 63.0% relaxed and 11.8% strict success. The result is interesting because it isolates the source of long-horizon gains: the agent's memory and steering matter independently of policy memory, richer observations, or geometric tools. It also suggests an action model's capability is gated by how precisely it is steered, not only by what it learned.
Agent-side memory steers stateless robots through long manipulation tasks
2AM separates task memory from motor control, using language and optional 2D hints to guide a single RGB-only action model.
Top University
Yutong Hu · Fengjiao Chen · Xuezhi Cao · Renaud Detry
KU Leuven · Meituan Inc. · Flanders Make@KU Leuven
Research Digest··2 min read
In one line
Task memory for long-horizon manipulation can live outside the action policy; an agent-steered, stateless RGB action model reaches 76.3% on LIBERO-Mem.
Before you read this
Three ideas this paper builds onagent memoryA repository where an agent stores past interactions and outcomes to inform future decisions.200 papers →vision-language-action modelA robot policy model that maps visual observations and language instructions to actions, trained on demonstrations and often used for manipulation tasks.61 papers →failure attributionIdentifying which component or step in a system caused an observed failure, often using structured trace representations.115 papers →
Read it as
Hu et al. test whether long-horizon robot manipulation requires memory inside the action policy itself.
The authors built 2AM around a strict division of labor.
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