What it means
A node in the graph declares an input as required, but nothing is wired into it. ComfyUI cannot run a node whose required inputs are unsatisfied, so it stops and names the missing input.
This often appears after editing a graph — deleting an upstream node, or updating a custom node whose newer version added a required input that older workflows did not connect.
Common causes
- A mandatory input was never connected.
- An upstream node feeding that input was deleted.
- A node update added a new required input to an existing node.
- A reroute/connection was accidentally removed.
How to fix it
- 1
Locate the named input
The message names the missing input; find that socket on the flagged node.
- 2
Connect a compatible source
Wire an output of the correct type into the required input — for example a MODEL, CLIP, or CONDITIONING output as appropriate.
- 3
Check required vs optional
If you did not expect the input to be required, check the node’s current version — a package update may have promoted it from optional to required.
Frequently asked questions
Frequently Asked Questions
Quick answers to the most common questions.
Related errors
Make every ComfyUI run reproducible
Numonic captures the full workflow behind each ComfyUI generation — models, samplers, seeds, prompts, and custom nodes — so a setup that finally works is one you can find and rebuild, not re-debug.