PR #1780 adds specific except UrlElicitationRequiredError: raise blocks in tool handlers to prevent this exception from being wrapped as a tool error.

Per SEP-1036, UrlElicitationRequiredError is not a regular error—it's a protocol-level flow control mechanism equivalent to elicitation/create. It needs to propagate as a JSON-RPC error response.

If more continuation-style exceptions are added in the future, consider an attribute-based pattern:

class McpError(Exception):
    propagate_through_tool_handlers: bool = False

class UrlElicitationRequiredError(McpError):
    propagate_through_tool_handlers = True

For now, YAGNI applies—we only have one such case.