pip Manager’s legacy-UI mode is a third API dialect
Popular Docker images (e.g.yanwk/comfyui-boot) hardcode
--enable-manager-legacy-ui, which swaps in Manager’s bundled 3.x server under the
/v2 prefix — a server with no queue/task route, so every custom-node and
model operation died with a 405. comfyui-mcp now detects the mode
(/v2/manager/is_legacy_manager_ui) and speaks its queue/batch dialect (#235),
on top of the two Manager generations it already handled. Manager detection also
validates the probe payload, so an SPA answering 200 to everything can’t masquerade
as a Manager API. Both root causes came from two excellent community bug reports.