You'll notice
Setting CLAUDE_CODE_USE_GATEWAY alone no longer switches Claude Code into gateway auth mode
What
Claude Code picks an authentication provider internally, such as bedrock, vertex, mantle, firstParty or gateway. Previously, if none of the other provider settings matched, having the CLAUDE_CODE_USE_GATEWAY environment variable set was enough on its own to fall back to gateway mode. That fallback branch has been removed.
Why
Setting CLAUDE_CODE_USE_GATEWAY by itself will no longer cause Claude Code to use the Cloud gateway; anyone relying on that variable alone to select gateway mode should check what else is now required.
Names in the bundleCLAUDE_CODE_USE_GATEWAY
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
the finding doesn't say what, if anything, now determines gateway mode instead, or whether another condition must accompany this variable
Anthropic's release notes agree
Fixed a 2.1.265 regression affecting LLM-gateway and proxy setups: the undocumented CLAUDE_CODE_USE_GATEWAY environment variable, previously…