Claude Code 2.1.236–237 · default model env, idle notify, Concise style, gateway cache

ANTHROPIC_DEFAULT_MODEL sets the model new sessions start on; a /model pick still overrides and persists (unlike ANTHROPIC_MODEL). Cross-session SendMessage gains opt-in notify_when_idle (one-shot, macOS/Linux). macOS sandbox: wildcard read-denies (e.g. **/.env) win inside allowed regions and cover directory contents. 2.1.237 fixes prompt caching through LLM gateways / custom base URLs and adds a built-in Concise output style under /config.⁴⁵

Relevant to: Claude Code daily drivers on multi-session hosts, gateway proxies, and anyone drowning in preamble