Here is my takeaway from attending the 89th conference of the North American Network Operators' Group (NANOG 89).

Two teams running the identical Cursor or Claude Code installation can produce wildly different output; the gap almost always traces back to one thing. This part covers the extensibility layer: skills, subagents and Agent Teams, rules, MCP, the emerging ACP standard, plugins and hooks. Tool selection is a thirty-minute decision; building this layer is a six-month investment that compounds into a real competitive moat.