What It Does
CheckpointLoaderSimple is the standard model loading node. It reads a checkpoint file from the ComfyUI models directory and separates it into three components: the diffusion MODEL (UNet), the CLIP text encoder, and the VAE (image encoder/decoder).
The checkpoint filename is the only parameter, but it is the single most important provenance data point—it determines the base aesthetic and capabilities of the entire generation pipeline.
The provenance challenge with checkpoints is that ComfyUI records the filename, not a file hash. If users rename model files or use different files with the same name across machines, the provenance chain breaks silently.
Inputs
ckpt_nameSTRINGCheckpoint filename from the models directory.
Outputs
MODELMODELThe diffusion model (UNet).
CLIPCLIPThe CLIP text encoder.
VAEVAEThe VAE encoder/decoder.
What Numonic Captures
- Checkpoint filename
- Model type (SD 1.5, SDXL, Flux, etc.) when detectable from workflow context
Known Gaps
- Model file hash — filename only, not a checksum
- Model version or training details — not embedded in most checkpoints
- Download source or model card URL
Related Nodes
Capture ComfyUI metadata automatically
Numonic extracts workflow metadata from every ComfyUI generation — models, samplers, seeds, prompts, and custom nodes. Track provenance, maintain compliance, and never lose a workflow.