https://www.techradar.com/news/your-amazon-echo-is-about-to-get-way-more-useful

You can load an Amazon Echo up with as many of its voice-activated Skills as you like, but if you can't remember the specific triggers for them, the Alexa voice assistant stops feeling quite so useful.

Amazon is working to smooth out the search for specific Skill commands however. It's rolling out a new beta feature called CanFulfillIntentRequest, which will let the developers of Skills tell Amazon the kind of questions their tool can answer.