Claude Code makes forked subagents the default — children inherit the parent's conversation and prompt cache
Claude Code 2.1.232 (Aug 13, 2026) flips subagent forking on by default: a spawned subagent now inherits the full parent conversation and shares its prompt-cache prefix instead of starting cold, and nested spawn depth defaults to 3. Practitioner writeups put the input-token saving for children 2..N at up to ~90% because they hit the cached prefix rather than re-paying to rebuild context. Opt out with CLAUDE_CODE_FORK_SUBAGENT=0 or CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH=1. For anyone fanning out research or review agents, this changes the cost math enough that fan-out patterns previously rejected as too expensive are worth re-testing — and it silently changes isolation assumptions, since forked children can now see everything the parent saw.
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