Internal signal that the modern single-endpoint POST returned an HTTP 400/404/405, the trigger for the legacy HTTP+SSE (2024-11-05) fallback. Surfaced to McpClient.connect so it can drive the fallback.
Internal signal that the modern single-endpoint POST returned an HTTP 400/404/405, the trigger for the legacy HTTP+SSE (2024-11-05) fallback. Surfaced to McpClient.connect so it can drive the fallback.