Missing From Source or Unavailable Documentation
The following variables appeared in the source ENV.md but either lacked sufficient public documentation or have internal-only purposes:
ANTHROPIC_CUSTOM_MODEL_OPTION_DESCRIPTION— documented (see Model Configuration)ZELLIJ— Detected when running inside Zellij multiplexer (terminal detection variable)
All documented variables above include type information, defaults, and practical usage examples where the information was available through the source doc and public API references.