Self-hosted gateway upstreams can forward your identity and email, and config refuses it for Anthropic hosts.
What's wrong with this entry?
Anthropic upstreams in gateway config accept a new forward_user_identity option. With it set, requests carry the signed-in developer's identity-provider subject and email as x-litellm-end-user-id, x-claude-gateway-user-id and x-claude-gateway-user-email, for a proxy you run yourself. Config validation refuses the option when the upstream base_url host is anthropic.com, any subdomain of it, or the AWS external-Anthropic pattern, so user emails never reach Anthropic.
- When an
oidcblock is present alongside it, a warning names exactly which fields get forwarded. - Off unless you add the option to an upstream.
forward_user_identity is for identifying users to a proxy you run at base_url; it is refused for
Strings lifted out of the shipped bundle, so the claim above can be checked against them.