Camera naming (model card vs embodiment)¶

VLA checkpoints declare image input features (e.g. observation.images.image, observation.images.wrist_image). The LeRobot Local provider routes a robot/sim camera onto each of those features using the embodiment's obs_rename map ({runtime_camera_name: "observation.images.*"}).

The trap: a model's HuggingFace card often describes its cameras in human terms ("top + side", "third-person + wrist") that do NOT match the runtime source key the embodiment expects. If you name your sim cameras after the card ("realsense_top"), the rename step never produces the model's image features, and inference fails with a confusing image_keys missing from observation.

run_policy / eval_policy catch this with a cheap pre-flight check BEFORE any model weights download, returning a status=error that names the expected source camera keys and how to fix it. See the pre-flight check.

Translation table¶

Use the embodiment source key column when naming sim cameras (sim.add_camera(name=...)). The model-feature column is what the checkpoint declares internally.

Model	Embodiment	Camera source key (`add_camera` name)	Model image feature
`allenai/MolmoAct2-SO100_101`	`so100` / `so101`	`front`	`observation.images.image`
`allenai/MolmoAct2-SO100_101`	`so100` / `so101`	`wrist`	`observation.images.wrist_image`
SmolVLA (single-cam SO arm)	`so100` / `so101`	`front`	`observation.images.image`
pi0 / pi0-FAST (Aloha)	`aloha`	`cam_high`	`observation.images.cam_high`
pi0 / pi0-FAST (Aloha)	`aloha`	`cam_left_wrist`	`observation.images.cam_left_wrist`
pi0 / pi0-FAST (Aloha)	`aloha`	`cam_right_wrist`	`observation.images.cam_right_wrist`

The authoritative source for every embodiment is its entry in strands_robots/policies/lerobot_local/embodiments.json (obs_rename). When in doubt, read the obs_rename keys for your embodiment - those are exactly the camera names the runtime observation must contain.

Two ways to satisfy the check¶

Rename your cameras to the expected source keys:

sim.add_camera(name="front", position=[0.22, 0.025, 0.6], target=[0.22, 0.025, 0])
sim.add_camera(name="wrist", parent_body="so101/gripper")

Keep your names and override - obs_rename_override merges OVER the embodiment's obs_rename, so a custom camera name routes onto the model's image feature without renaming:

sim.run_policy(
    robot_name="so101",
    policy_provider="lerobot_local",
    policy_config={
        "pretrained_name_or_path": "allenai/MolmoAct2-SO100_101",
        "embodiment": "so101",
        "obs_rename_override": {
            "realsense_top": "observation.images.image",
            "realsense_side": "observation.images.wrist_image",
        },
    },
)

Camera naming (model card vs embodiment)¶

Translation table¶

Two ways to satisfy the check¶

See also¶