Simplicity is the ultimate sophistication. ~ Leonardo da Vinci

Simplicity is a core Principle of Agile Software Development.  

Simple things are easy to understand, and straightforward to implement. Simple things do not cost a lot of time (or money) to implement and are therefore also easy (painless) to revert. But how does it look in practice? What does it mean to keep it simple? 

Here’s a short review explaining the implementation of the agile 10'th principle - simplicity.

Software Design Documents in Agile Development

It would be grossly unfair to say that agile methods do not require any prior design. Agile methods are adaptive, not unplanned or undisciplined. When the development is based on agile methodology such as SCRUM and especially, distributed SCRUM, at some point, the need for design document becomes key to success of sprint delivery with as lesser technical debt as possible. What are those dcuments and what is the way to deal with creating them?

Agile and software Architecture design- overview

It would be grossly unfair to say that agile methods do not require any prior design. Agile methods are adaptive, not unplanned or undisciplined. I am by no means an evangelist for these techniques, but I do recognize that they go far beyond merely jumping in and coding away.