What
In auto mode, Claude acts without asking you first. A request may be refused with HTTP error 400 or 422, or in some cases 403, and then succeed when sent again without auto mode's dangerous-tool-use beta header and safeguards field. When that happens, Claude Code stops sending them. A warning is logged.
The server-side check of Claude's actions then stays off:
- for the rest of the conversation, normally
- until Claude Code restarts, when you connect through a gateway
Why
If your organization routes traffic through a gateway that rejects this header, auto mode keeps working instead of failing. Be aware that the server-side safety check of Claude's actions is off once this happens.