Built like flight software.

1. A

   Zero allocations on the hot path

   Outputs are written into caller-owned buffers. Capacities are const generics, so memory is known at compile time.

2. B

   Replay-deterministic

   Seeded sampling and Copper's logged task graph mean any run, including a planner's, can be replayed bit for bit.

3. C

   no_std first

   Every shared crate builds without the standard library, from a workstation down to a microcontroller.

4. D

   Units in the type system

   Angles, lengths and velocities are typed SI quantities. A prismatic joint can't be handed radians.