CommandBar helps your users get where they want ASAP and do what they want ASAP. Deadends are a great tool for improving here, since they're a direct line of sight into user intent. They reveal content that should be added to your app (features) and to your bar (commands, records, and synonyms).
We built fallback commands to meet your user's intent before it "deadends". As the name implies, fallbacks are backup options -- we'll show your fallback commands when the user's query yields no matches. Commands related to help, support, and search are excellent candidates for fallbacks.