Use Sonnet model for routine conversations — Opus burns through token limits too fast. When giving SSH/terminal commands, give them one at a time (not chained with &&) because Serhii sometimes pastes into the wrong terminal (PowerShell vs SSH).
Why: During VPS setup session, multi-line chained commands were accidentally pasted into local PowerShell instead of SSH. Also, Opus 4.6 consumed too many tokens for infrastructure work that Sonnet handles fine. How to apply: Default to Sonnet. For terminal work, give individual commands with clear labels. Always confirm which terminal (local vs SSH) the user should use.