The honest tradeoffs

Subagents are not free. Cursor's docs lay out the costs candidly: each subagent has its own context and token usage, so running five in parallel uses roughly five times the tokens; there is startup overhead because each gathers its own context; and for a simple task a subagent can be slower than the main agent because it starts fresh. The benefit is context isolation and parallelism, not raw speed. The anti-pattern to avoid: do not create dozens of vague "helper" agents. Cursor warns that fifty subagents with descriptions like "helps with coding" are useless because the agent cannot tell when to use them. Start with two or three focused ones with sharp descriptions.