arkennemasis fal · Flux 3 Draft Enhance · $0.29/s

FLUX 3 is the thing nobody can download. flux-2.md §12 is precise about it: FLUX 3 Video shipped as early access, API plus private weights, with the open-weight Dev backbone still "coming soon" and no date. So if you want FLUX 3 motion, you're calling it - and at $0.17–0.29 per second, calling it blind on a 10-second shot is $3 of guesswork.

The draft nodes exist for exactly that. ArkFal_blackforestlabs_flux_3_draft_enhance is the other half: it takes the encrypted draft bundle a draft node produced and re-renders it at full quality, at $0.29 per second of the enhanced video (1080p, synchronized audio included).

Why the two-step is worth it

A draft costs $0.06/s. The full render costs $0.17–0.29/s. So the pattern is: draft at 5–6 cents a second, check the motion, the composition, the timing - and only then pay for the finish. On a ten-second clip you've spent $0.60 to find out whether the idea works instead of $2.90. Do that five times and the draft stage has paid for itself several times over.

The pitch on the node's own description is that it's the same seed and the same motion, "no re-planning" - the draft bundle carries enough state that the enhancement is a render, not a fresh roll. That's the difference between a preview and a lottery ticket.

What you set

Two required fields, which is why this article is short. It's a finisher, not a generator.

• draft_cache_url - the encrypted draft cache bundle, as a URL or data URI. This is where the sharp edge lives; see below.
• safety_tolerance - 0 is strictest, 4 most permissive, default 2.

Then the usual optional batch: max_cost_usd (default $20, checked before anything is sent; 0 removes the cap), reuse_identical_run (on by default), extra_json, max_concurrent.

Outputs: video (a VIDEO value), video_path (the MP4 on disk), and info with the request id, the estimate and fal's full answer.

The one gotcha, and it's a real one

The draft nodes hand you draft_cache_path - a local path, e.g. output/fal/blackforestlabs_flux-3_text-to-video_draft/.... This node wants a URL. A text box full of local paths gets sent to fal verbatim, and fal can't fetch your hard drive, so wiring the path straight into draft_cache_url will not work.

The bundle's fal URL is in the draft node's info output - fal's full answer, including the draft_cache file object - and the same answer is written to output/fal/_requests.jsonl when the draft completes. That's the URL you paste. Keep the draft's info around; it's your ticket to the enhance.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/Hishamahmer/comfyui-arkennemasis

Or ComfyUI Manager → search arkennemasis → install → restart. Then your key, in the .env file next to run_nvidia_gpu.bat (or in the ComfyUI folder):

FAL_KEY=your-key-from-fal.ai/dashboard/keys

No key box on the node, no models to download - fal holds FLUX 3, and fal is the only place it runs.

Practical notes

The estimate here can't measure a connected clip; there isn't one. The quantity is unknown to the browser-side badge, so the title keeps showing a rate while the real dollar figure appears at run time, after the node has inspected the bundle.

If ComfyUI restarts mid-enhance, the job doesn't die - it keeps running on fal, and fal Recover Result (in the same arkennemasis/fal/Tools menu) collects it by request id for free. The request id is in output/fal/_requests.jsonl.

Results land in output/fal/blackforestlabs_flux-3_draft-enhance/. And because reuse_identical_run defaults to on, re-running the same enhance won't bill you twice - which makes it safe to experiment with your graph after the expensive part has finished.