There is one lead who is accountable for the result of this project. This needs to be someone whose time is at least 80% dedicated to it, and who can champion the mission inside and outside of the team.

Roles and responsibilities are clear and agreed upon. The project has people with the right blend of skill set. Acknowledge that team members can change by stage.

The team has a common understanding of why they're here, the problem/need, are convinced about the idea, confident they have what they need, and trust each other.

It's clear what success means from a business and user's perspective, and there is a unique value proposition in place for the target users and to the business. Success is defined, with a goal, and how it will be measured.

Some sort of demonstration has been created and tested, that demonstrates why this problem needs to be solved, and demonstrates its value.

The project is summarized in a one-pager and shared with anyone so that they understand the purpose of the project, and its value.

Clear understanding of complexity, infrastructure involved, risks, resources, effort, and timeline. Clear understanding of who we depend on, and who depends on us. 

The team is making incremental progress by shipping concrete iterations to stakeholders (and even better to production), learning along the way, and implementing lessons learned, resulting in greater success.