I've been running OpenClaw (which sits on top of similar primitives) to manage multiple simultaneous workflows - one agent handles customer support tickets, another monitors our deployment pipeline, a third does code reviews. The key insight I hit was exactly what you describe: context engineering is everything.
What makes OpenClaw particularly interesting is the workspace-first model. Each agent has AGENTS.md, TOOLS.md, and a memory/ directory that persists across sessions. You can literally watch agents learn from their mistakes by reading their daily logs. It's less magic, more observable system.
The YOLO-by-default approach is spot on. Security theater in coding agents is pointless - if it can write and execute code, game over. Better to be honest about the threat model.
One pattern I documented at howtoopenclawfordummies.com: running multiple specialized agents beats one generalist. Your sub-agent discussion nails why - full observability + explicit context boundaries. I have agents that spawn other agents via tmux, exactly as you suggest.
The benchmark results are compelling. Would love to see pi and OpenClaw compared head-to-head on Terminal-Bench.