comfy-preflight

A gate that runs on a ComfyUI workflow graph in the seconds before it is submitted, and halts a submission that would spend credits producing a known-wrong result.

It does not submit. It does not fix your graph. It names the defect and the node, and the caller decides.

Why it exists

A Comfy Cloud dry_run PASS does not prove link sanity. A hand-retyped payload with a self-referencing node link — VAEDecode.samples = ["14", 0], the node pointing at itself — returned status: validated.

The provider’s validator answers is this graph well-formed enough to run. It does not answer is this the graph you meant. Every check here lives in that gap, and each one was paid for by a run that got past dry_run.

The framing that governs everything else

Submission is the irreversible act with no real undo, and a preflight is a compensator you run BEFORE instead of after.

A completed cloud job is billed. The only compensator afterwards is cancel it if it is still queued, otherwise none — which is not much of a compensator. So this package runs before the irreversible step, and everything about it follows from that: it reaches nothing it does not need, writes nothing anywhere, and cannot be turned off at a call site.

What it does not do

• It does not submit. Nothing here spends a credit or contacts a provider.
• It does not fix a graph. No rewiring, no auto-inserted loader, no rounded frame. A graph a gate repaired is a graph nobody reviewed.
• It does not judge the output. It never sees one.
• It does not model VRAM or predict fit. Measured dead end: peak was 31.7–32.0 GB across three runs regardless of the reserve setting, because the runtime stages to fill whatever it sees free — freeing 6.5 GB made the working set grow 6.1 GB. A fit prediction here would sell a number the record already refuted.
• It does not replace dry_run. It runs beside it.

Where to go next

page	what’s in it
Getting started	install by three doors, and the first run
The checks	what each check asserts, and what it declines to
The adoption contract	why the gate must be called in-process, and the exit codes
The envelope table	check 8’s cited data, and the band that is not on the card