#35403 Per-request x-mcp-{server_alias}-authorization header not applied to MCP server auth resolution (resolves as no-auth)
**Environment**: litellm 1.81.14 (proxy), MCP server registered with no static `auth_type`/`auth_value`/`static_headers` ā relying entirely on per-request client headers (the documented alternative to a shared static credential).
**Config**: ```yaml mcp_servers: myserver: url: "http://internal-host:9099/mcp" transport: "http" ```
**Repro**: `POST /mcp/` a `tools/list` request with header `x-mcp-myserver-authorization: Bearer <token>`.
**Expected**: LiteLLM forwards `Authorization: Bearer <token>` to the upstream server. With `x-litellm-mcp-debug: true` set, the response should include `x-mcp-debug-auth-resolution: per-request-header`.
**Actual**: `x-mcp-debug-auth-resolution: no-auth`. The upstream MCP server receives no valid `Authorization` header at all (confirmed via a 401 from the upstream server's own access logs, captured at the same timestamp as the LiteLLM request). Because of this, any tool call that needs the caller's real per-user identity fails to resolve one ā `tools/list` alone appears to "succeed" only because it doesn't require a valid identity to return tool schemas.
**Investigation notes**: Traced through `mcp_server_manager.py`: - `server.server_nā¦