Claude Code's fallbackModel chains up to three models for resilience.

Recent releases added a fallbackModel config that tries up to three models in order when the primary is unavailable or rate-limited. (Claude Code Docs) For long-running autonomous loops this stops a single provider hiccup from killing a session mid-task. Put a cheap model last in the chain so degraded runs continue instead of erroring out. Combined with this month's nested-subagent support (background trees capped at 5 levels deep), Claude Code is becoming a real orchestration layer, not just a chat loop.