Effective architecture sketches. Collaboration and "moving fast" aren't terms that many people associate with the software architecture role, yet they're both essential.
Why? Because collaborating on the software design process provides a basis for coming up with a better solution and it paves the way for collective code ownership. And moving fast requires "just enough" up front design to avoid costly rework, which sits conveniently in that vague area between big design up front and foolishly hoping for the best. Costly rework can be caused by a number of things, ranging from not mitigating the key technical risks through to the team not understanding the high-level structure and therefore being able to work towards the same vision.
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