For MCP servers (outside programs that give Claude Code extra tools), the extra headers you configure with headers or headersHelper are now also sent during two steps of OAuth sign-in:
- Looking up the server's sign-in details
- Revoking a sign-in token
Before, these requests sent no configured headers. The headers are only sent to addresses on the same origin as the server (the same scheme, host and port). A redirect to a different origin is refused with "Refused a redirect to another origin". Claude Code can also now refuse to connect with the message "MCP server refused at a reserved address".
MCP servers that need a header before sign-in can begin now work, while your headers are kept from leaking to other sites.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
"headersHelper": "<string>"third-party/claude-desktop/configuration-changelog see the edit
A create request takes the Console's settings except **Provider**, so enter your observability platform's endpoint URL and headers yourself. Set `traces.max_content_bytes` (csharp, go: `Traces.MaxContentBytes`; java, php: `traces.maxConten…manage-claude/opentelemetry/api see the edit
# Request-Id headers, to stderrbuild-with-claude/claude-platform-on-aws see the edit
Anthropic's documentation has since written up headers, on claude-platform-on-aws.
Fixed MCP OAuth sign-in, token refresh and sign-out not sending configured headers/headersHelper values, which broke servers behind an…