Comfyui Launch Flags
Pick the right ComfyUI startup flags for VRAM, attention, caching, and speed.
Install
npx skills add artokun/comfyui-mcp --skill comfyui-launch-flags -g -a claude-code -y- Repository
- artokun/comfyui-mcp883
- Category
- Writing
- Updated
- 9d ago
- License
- MIT
- Context cost
- Mediumabout 2,865 tokens
- Runs scripts
- No, instructions only
What it does
Pick the right ComfyUI startup flags for VRAM, attention, caching, and speed. The full decision matrix for OOM (--novram / --cache-none / --disable-smart-memory), shared-VRAM creep on Windows (--reserve-vram N), model-switching with big text encoders (--cache-none), high-VRAM throughput (--gpu-only / --highvram), and attention-backend selection (--use-sage-attention for speed, --use-pytorch-cross-attention as the highest-quality / Z-Image-safe fallback). Also the acceleration-stack + Blackwell/RTX 5000 (sm_120) notes. Use when a graph OOMs (especially long video like LTX 2 / WAN), when the GPU spills into shared VRAM and slows to a crawl, when switching between models eats all RAM, when Z-Image produces black/garbled output under Sage, or when deciding which attention backend to launch with. Flag names verified against upstream comfy/cli_args.py; see Sources.
ComfyUI launch/performance flags
Overview
CLI flags passed to main.py control ComfyUI's runtime behavior
(e.g. python main.py --reserve-vram 2 --use-sage-attention). The three that
matter most for making a graph run rather than OOM or crawl are the
VRAM strategy, the attention backend, and the cache mode. This skill
is the decision matrix for choosing them.
⚠️ Verification note (August 2026). Every flag below was checked against upstream
comfy/cli_args.pyon current master. ComfyUI adds/renames flags often, when in doubt runpython main.py --helpin the target install and prefer that over this list.--enable-triton-backend/--disable-triton-backendARE ComfyUImain.pyflags on master (they used to be documented as SwarmUI-only; that is stale).--use-ck-attentionis kitchen INT8 attention, nosageattentionwheel. A June ComfyUI checkout still pins comfy-kitchen 0.2.10 and lacks--use-ck-attention;kitchenaction:"status" reports ComfyUI-side flag support, not only the kitchen version. Usekitchen/panel_kitchento see what this GPU can actually run.
How to apply today. The MCP's
restart_comfyui(withaction: "start") currently replays the exact argv of the previous run. It does not compose fresh flags. So set these when you launch ComfyUI yourself (thepython main.py …line, arun.bat/shell alias, or the SwarmUI backend args box), and the tool will preserve them on restart. Injecting flags through the tool is a tracked follow-up.
