Model-agnostic

A design that lets your company, product or service swap one model or vendor for another with little rework, so it is not locked in to one provider.

Also called

LLM gateway An intermediary that your company's calls to models route through; when it holds the only API keys, it is both a control point and a log of every call.
Sovereign AI An approach where a country or company keeps its AI (models, data and computing) under its own control and laws, insulated from foreign vendors and jurisdictions.