Most design principles can't survive contact with an agent

"Be consistent." "Delight the user." "Reduce friction."

These worked when the audience was a designer who could interpret them. They don't work when the audience is a model loading context at runtime.

Agents need skills, not slogans. A skill is a specific, executable instruction: when you see X, do Y, not Z, and here's an example. It's the same judgment a senior designer carries in their head, written down in a form the agent can actually use.

This changes what design leadership produces.

The deliverable isn't a principles deck anymore. It's a library of skills the rest of the org, including the agents, can load on demand. The org that builds this library first compounds its design quality across every surface, every sprint, every agent session.

Principles were aspirational. Skills are operational.

That's the shift.