Build a simulator adapter

Runway’s Praxis-1 repository includes a MuJoCo simulation that runs the model locally. It does not connect a simulator to the Reactor endpoint. You build the connection between your simulator and Reactor. This guide gives the necessary mapping. It does not include an adapter that you can run. First, use Get your first actions to check the API connection. Then build the adapter with the API reference.

Simulator side	Reactor mapping
Exterior camera, Wrist camera	Publish the `exterior` and `wrist` tracks no larger than 512 × 288 (width × height).
End-effector pose and gripper	Encode measured rows in `set_robot_state_json`; select `pose_frame` for your frame.
Task instruction	Send `set_task`.
Policy query	After executing a chunk, send `set_executed_step` with its `step`.
Reply	Match `step`, validate the rows, and send the absolute pose targets through the simulator controller.

Execute the rows at 15 Hz with a controller that accepts end-effector pose targets. Decide if the simulator pauses or continues while it waits for inference. Record that decision with your results. A reply to test inputs only checks the API connection. Before you move to hardware integration, evaluate task success in the simulator. Also measure the age of observations when actions execute, and make sure that actions stay in your limits.

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Policy inference

Simulation

Build a simulator adapter