I've finally hit upon the answer. Previously, this question had been so daunting to answer because it is inherently the wrong question, when you're just starting out. At least, if you translate "tool" to mean "software application." eScrum or Mingle or VSTS does not make you agile. Your philosophies and your strategies make you agile.
Here are the tools that we use:
- The Agile Manifesto.
- Shared sense of ownership, where developers, testers, and business people have an equal stake in, and equal responsibility to, the success of the project. We're all pulling together.
- Rigorous software engineering practices, especially source control, continuous integration, readable (soluble? grokkable?) code, and automated unit tests.
- Communication. All the damn time. As much like face-to-face as you can manage. We do our best with a globe-spanning agile team; if your teammates all reside in the same city, then for goodness sake take advantage of that luxury and meet in person.
- Frequent feedback, in many different forms. CruiseControl always tells us the health of our build; testers are testing functionality every day; business partners are reviewing and providing corrections all the time. The elapsed time between making a change and knowing if it is good is as short as possible.
- Retrospectives, where the team talks honestly and candidly about what is going well and what could be improved, and then takes direct action on those improvements. Contrast this with end-of-waterfall "Lessons Learned" sessions; by the end of the project, it's too late, there's no point in trying to implement any changes because you won't be working with these people. Instead, meet every week or two weeks, or whatever works for your team, to decide what you want to do together to help your team.
- Empowered, self-directed team members, who collectively decide what fits best with their team. I'm happy to tell you which tools (from the "software application" sense of the word) we use and how long our sprints are and what processes we follow, but your team is best qualified to determine what will work for your team.
From this sense, what tools do you recommend?