Custom policies¶

# my_policy.py
from strands_robots.policies import Policy, register_policy

class MyPolicy(Policy):
    async def get_actions(self, observation_dict, instruction, **kwargs):
        return [{"motor.0": 0.5, "motor.1": -0.2}]   # list of action dicts

    def set_robot_state_keys(self, keys: list[str]) -> None:
        self._keys = keys

    @property
    def provider_name(self) -> str:
        return "my_provider"

    @property
    def requires_images(self) -> bool:
        return False   # True (default) = cameras required; False = state-only

register_policy("my_provider", lambda: MyPolicy, aliases=["mine"])

# usage
import my_policy                              # side-effect: runs register_policy
from strands_robots.policies import create_policy
from strands_robots import Robot

policy = create_policy("my_provider")         # or "mine"
sim = Robot("so100")
sim.run_policy(robot_name="so100", instruction="do something",
               policy_object=policy, duration=5.0)

Permanent registration (JSON)¶

Add to strands_robots/registry/policies.json:

{
  "my_provider": {
    "module": "my_pkg.my_policy",
    "class": "MyPolicy",
    "shorthands": ["mine"],
    "description": "My custom policy."
  }
}

The factory imports lazily on first use.

Aliases and shorthands are validated on load: each must be unique across providers and must not collide with a different provider's canonical name (that would silently shadow it, since lookups resolve through the alias/shorthand map before the canonical name). Listing a provider's own name in its shorthands is allowed and idiomatic -- it is how the bare name resolves. A colliding entry raises ValueError at registry load.

ABC contract¶

Method / property	Abstract	Default
`async get_actions(obs, instruction, **kw) -> list[dict]`	yes	-
`set_robot_state_keys(keys)`	yes	-
`provider_name` (property)	yes	-
`requires_images` (property)	no	`True`
`reset(seed=None)`	no	no-op
`get_actions_sync(...)`	no	sync wrapper

Action value convention¶

get_actions returns a list[dict] -- one dict per control tick, each mapping a robot state key (joint/actuator name) to its target value for that tick. The value MUST be JSON / python-native:

a python float for a single-DOF actuator, or
a list[float] for a multi-DOF actuator group.

Do not return raw np.ndarray objects. If your policy computes actions with numpy / torch, coerce before returning (float(v) for scalars, v.tolist() for arrays). This lets downstream consumers treat every provider's output uniformly (float(v) on a scalar, len(v) on a group) regardless of the policy's internal compute backend. The list length is the action-chunk horizon; consumers execute it at a fixed control rate (e.g. 50Hz). See strands_robots/policies/mock.py for the canonical reference.

Custom policies¶

Permanent registration (JSON)¶

ABC contract¶

Action value convention¶

See also¶