What
DEBUG_CLAUDE_AGENT_SDK is an environment variable, a named setting passed to a program from outside. It controls debug file output for the Agent SDK. Claude Code now reads it directly from the live process environment and interprets the value as on or off, instead of reading it from a copy saved earlier.
Why
A value set after startup is now seen, and the variable is read as a switch rather than simply checked for being present.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say which values count as on.