Pattern: Harnesses Are Converging on Hard Resource Caps Because Agents Now Spawn Agents

Claude Code Changelog·high signal

Within days, Claude Code capped concurrent subagents at 20 and disabled nested spawning by default, Cursor exposed a `subagentStart` hook, and Claude Code fixed `--max-budget-usd` not applying to background subagents. All three are the same recognition: recursive delegation has no natural termination condition, so the ceiling must live in the harness, not the prompt. Expect spawn depth, concurrency, and spend to become standard first-class config across every agent CLI this quarter.