Open by design is an architectural choice

Openness matters when a system can change one layer without forcing every other layer to change with it. For a robotic runtime, that means models, providers, agents, skills, tools, and interfaces should be able to evolve independently.

The practical mechanism is a set of explicit, typed contracts around plans and actions. Vendor-specific behavior stays at the edge instead of leaking into the core.

Choice without ambiguity

Replaceability does not mean an absence of rules. The execution boundary still defines identity, policy, resource ownership, and allowed transitions. Open components can propose many paths; the runtime decides which paths are allowed to become action.

This is how openness and governance reinforce each other instead of competing.