tmux.

Same words, different architectures. When to delegate with subagents, when to collaborate with agent teams, and when tmux background sessions beat both.

619 commits in two months. The two load-bearing choices: Rust, because the compiler shortens the agent's iteration loop, and tmux, because agents are long-running processes that have to survive the laptop.

Every long-running agent lives in a detached tmux session named after its job. Six months of fleet operation distilled to one rule.