Marvellous insights from Mark on how the robustness principle can and should be applied to styeguides and pattern libraries (‘sfunny—I was talking about Postel’s Law just this morning at An Event Apart in Boston).
Being liberal in accepting things into the system, and being liberal about how you go about that, ensures you don’t police the system. You collaborate on it.
So, what about the output? Remember: be ’conservative in what you do’. For a design system, this means your output of the system – guidelines, principles, design patterns, code, etc etc. – needs to be clear, unambiguous, and understandable.