Advertise URL elicitation
Includeelicitation.url as an object in the client’s initialize capabilities. The following handshake uses the MCP 2025-11-25 URL elicitation contract:
Initialize request
null, true, or form-only elicitation does not enable it. Advertise it only when your client implements the browser handoff and completion handling.
Finish initialization with notifications/initialized. Preserve the returned Mcp-Session-Id and negotiated MCP-Protocol-Version on subsequent requests. These are transport state owned by the client, not tool arguments.
Present the authentication link
Whenexecute encounters connection_required or reconnect_required, Engine starts a consent session. The MCP tool call returns a JSON-RPC error with code -32042 and an entry in error.data.elicitations:
Authentication required response
action is reconnect and the message asks the user to reconnect.
Handle this error in the MCP client and offer a Connect account button. Keep the authorization URL in that interaction rather than forwarding it into the model’s context. Open it after the user’s approval; collect passwords and provider consent only in the browser. Opening the URL is not proof that authentication completed.
Next, handle completion and resume the agent.