Opus 5 delegates to subagents more readily — and Claude Code 2.1.219 just raised nested spawn depth from 1 to 3 by default

Claude Platform Docs·high signal

Anthropic documents that Opus 5 "delegates to subagents more readily than prior models," which "multiplies cost and time when applied to small tasks," and publishes a paste-in constraint block: delegate only for large genuinely-independent parallelizable work, never to verify your own work, and prefer one subagent over several. On the same day, Claude Code v2.1.219 raised the default nested subagent spawn depth from 1 to 3 — meaning a subagent can now spawn a subagent that spawns a subagent unless you set `CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH=1`. Those two changes compound in the wrong direction; if you run agent fleets on a subscription or a fixed budget, set the env var and add the delegation cap to your system prompt now.