ComfyUI startup arguments (CLI args) are now fully exposed on RunComfy. You can pass any of the flags supported upstream by ComfyUI directly into your machine at launch time. The complete, authoritative list of arguments lives in the official ComfyUI source code: comfy/cli_args.py.
This FAQ walks through the three places where startup arguments can be set, persisted, and reused on RunComfy.
⚠️ Tip: Invalid or incompatible startup arguments can prevent ComfyUI from booting, break specific features, or noticeably slow down execution — double-check every flag against cli_args.py before saving or deploying.1. Set arguments at launch via Advanced Settings
When you spin up a ComfyUI machine, expand the Advanced Settings panel on the launch screen. Any flags you enter here (for example --lowvram, --use-pytorch-cross-attention, --preview-method auto) are passed directly to the ComfyUI process at boot. Refer to cli_args.py for the full set of supported flags and their accepted values.
2. Arguments are preserved with Cloud Save
When you trigger a Cloud Save, the startup arguments used in the current session are stored alongside the rest of your workspace state. The next time you launch from that save:
- The previous arguments are pre-filled automatically, so you don't have to re-enter them.
- You can clear them entirely and launch with default settings.
- You can overwrite them with a completely new set of arguments.
3. Arguments travel with workflow Deployments
When you deploy a workflow, the startup arguments captured for that specific workflow version are applied automatically on every deployment run. This guarantees that the runtime environment matches the one the workflow was authored and tested against.
As with Cloud Save, you remain in full control — the arguments can be reviewed, edited, cleared, or replaced before any run.
References
- ComfyUI CLI argument source of truth: github.com/Comfy-Org/ComfyUI/blob/master/comfy/cli_args.py
- RunComfy: www.runcomfy.com