Sentinel is built by one engineer. Every message lands directly in his inbox and gets a reply from a person, not a ticketing system.
Primary channel. Replies come from a human within one business day.
Quick questions, shipping updates, occasional thinking-out-loud about the product.
Work-mode conversations - procurement, partnerships, hiring notes.
Issues, commit history, and the changelog's source of truth.
For bugs: a screenshot, the URL you were on, and roughly when it happened cuts triage time in half.