ManiSkillFormer: Demonstration-Free Compositional Manipulation via Geometric Contracts and Agentic Skill Graph

Carnegie Mellon University

Paper arXiv Video

Let agents specify what to perceive and how to move,
so the same robot skills work on new objects!

Abstract

Adapting robotic manipulation to new objects and tasks often requires additional demonstrations, policy fine-tuning, or manual engineering. Reusable manipulation skills can reduce this effort, but connecting their execution requirements to scene-specific geometry remains challenging. We present ManiSkillFormer, a framework for demonstration-free and compositional manipulation that connects perception and action through explicit geometric contracts. Building on reusable skill schemas, LLM agents generate contracts specifying the geometry primitives required by each skill, together with corresponding motion templates for semantic objects and task contexts. These contracts guide a perception module to ground task-relevant 3D geometry from observations, which is then used to instantiate reusable motion templates in a skill library. We evaluate ManiSkillFormer on a dual-arm robot across demonstration-free pick-and-place with 30 instances from 8 object categories, functional manipulation including unscrewing, pouring, pressing, and folding, and three long-horizon tasks. ManiSkillFormer achieves an average success rate of 88.97% for pick-and-place, 75.00% for functional manipulation, and completion rates of 50–80% across the long-horizon tasks, outperforming the evaluated baselines and two ablated pipelines. These results demonstrate the potential of explicit geometric contracts to support skill reuse and composition across objects and tasks without per-object policy fine-tuning or additional robot demonstrations.

Method

Given a language instruction, the planner retrieves a sequence of skills and their geometric contracts from AgenSkillGraph. Promptable 3D perception grounds the requested semantic primitives in calibrated multi-view observations. The grounded geometry then parameterizes reusable motion templates to generate Cartesian waypoints.

System overview: planner, geometric contracts, promptable 3D perception, and AgenSkillGraph.
System overview. Geometric contracts connect the requirements of reusable skills with scene-specific perception.Enlarge figure ↗Original PDF ↗

Agentic skill generation

Human experts define skill structures and contract schemas. During adaptation, a contract agent and a skill agent tailor these schemas to semantic skill–object pairs and their task context. At runtime, perception grounds the requested keypoints and surface normals to instantiate the motion templates.

Offline schema definition, contract and skill adaptation, and online grounding and execution.
AgenSkillGraph. Human-defined fields are shown in green and agent-generated fields in purple.Enlarge figure ↗Original PDF ↗

Demonstrations

Real-robot experiments on the Galaxea R1-Lite. Playback speeds are indicated in the footage.

Functional manipulation

Pouring, unscrewing, pressing, and folding require different geometric primitives and motion sequences. Contracts specify the interaction geometry for each skill.

Multi-object sorting

Repeated composition of pick-and-place skills across six objects.

Cone stacking

Stacking requires precise geometric alignment between objects.

Long-horizon manipulation

A sequence of picking, placing, and pouring. The grasp chosen for the cup must also support the subsequent rotation.

Results

We evaluate object generalization, functional manipulation, and long-horizon composition. A1 removes explicit geometric contracts; A2 generates each atomic skill’s contract and motion template independently, without conditioning on subsequent skills.

Object generalization

Pick-and-place across 30 instances from 8 object groups, with 17 trials per group (136 trials per method). The π0 baseline is fine-tuned with 50 demonstrations per object category.

Single-object pick-and-place success rates (%).
Object groupOursMOKAA1A2π0
Bottle / Cup94.1264.7176.4788.2441.18
Pen88.2441.1870.5988.2435.29
Cables / Towels94.1229.4194.1276.4729.41
Bowl100.0064.7188.24100.0082.35
Toys88.2458.8276.4788.2464.71
Tools82.3547.0694.1276.4735.29
Cone94.1264.7164.7170.5941.18
Lego structures70.5947.0658.8258.8235.29
Average88.9752.2177.9480.8845.59
Grasp selection with and without contracts for pens, cones, Lego structures, and tools.
Effect of geometric contracts. Explicit requests improve grasp selection for pens, cones, and Lego structures. The tool example also shows a limitation: the requested handle-center grasp can slip under the object’s weight.Enlarge figure ↗Original PDF ↗

Functional manipulation

Functional manipulation success rates (%), with 17 trials per task.
TaskOursMOKAA1A2
Unscrew button76.4723.5358.8252.94
Pour82.3547.0670.5958.82
Fold cloth edge to center64.7158.8235.2952.94
Press button76.4776.4770.5976.47
Independent generation versus joint generation for pouring and folding.
Dependencies between skills. Joint generation conditions the grasp on the subsequent pouring or folding motion.Enlarge figure ↗Original PDF ↗

Long-horizon composition

Complete-sequence successes out of 10 trials.
TaskOursMOKAA1A2
Pick and place 6 objects6/102/104/106/10
Stack cones8/103/105/108/10
Task C (11 steps)5/101/102/101/10

In Task C, the robot places yellow and blue Lego pieces into a cup, places a red Lego piece into a bowl, pours the cup into a box, and places the bowl into the box. Completion requires maintaining compatible intermediate states throughout the sequence.

BibTeX

@misc{yu2026maniskillformerdemonstrationfreecompositionalmanipulation,
  title = {ManiSkillFormer: Demonstration-Free Compositional
           Manipulation via Task-Conditioned Geometric Contracts},
  author = {Peiqi Yu and Mosam Dabhi and Shangtao Li and
            Bowei Li and Laszlo Jeni and Changliu Liu},
  year = {2026},
  eprint = {2609.16331},
  archivePrefix = {arXiv},
  primaryClass = {cs.RO},
  url = {https://arxiv.org/abs/2609.16331},
}