🐰Flux.1 Kontext - Text to Image

"Flux Kontext" usually means editing - hand it a photo, get an edited photo back. This node is the odd one out in the pack: there's no image slot anywhere on it, just a prompt box. It runs Black Forest Labs' Flux Kontext Pro or Max in pure text-to-image mode, which the models genuinely support - Kontext isn't only an editor, it's the full Flux Kontext generation stack, minus the editing half for this particular node. You'd reach for it when you want a base image with Kontext's specific strengths - BFL markets Max as having sharper prompt adherence and typography than the rest of the line - and then hand that result to the pack's Editing node for a second pass. That's the workflow actually worth building: generate here, edit there, chain as many edits as you like. Kontext's whole architectural point is holding a subject steady across an edit chain, because it concatenates the reference image straight into its context instead of bolting it on through an adapter embedding, so it doesn't drift the way IP-Adapter-style tools do.

Here's the part worth knowing before you go hunting for a key: this node does none of the generating itself. No weights ship with it, no VRAM required, because your prompt gets shipped over HTTPS to 兔子AI (TuZi AI, tu-zi.com) - a Chinese API reseller that fronts BFL's Kontext Pro/Max endpoints and bills per call in RMB (the README quotes roughly 2¢ USD for Pro and 4¢ for Max at current rates, though check TuZi's own panel before trusting old numbers - resellers reprice). It's a proxy in front of a proxy: TuZi calls BFL, BFL renders, TuZi hands the image back, the node decodes it into a ComfyUI IMAGE tensor. Nodes in this category get side-eyed on r/comfyui - people who've actually opened up similar API-relay Kontext nodes describe them flatly as "just a shell" once they see there's no local inference path at all. That's not a knock on this specific pack so much as the nature of the category: you're paying for BFL's hosted quality and zero setup, not running anything yourself.

The inputs that actually matter for a beginner: prompt (Kontext's text half wants a real sentence, not a tag soup), model (flux-kontext-pro or flux-kontext-max - Max costs double but BFL positions it as the no-compromise tier for consistency and typography, worth it if you're rendering text in the image), and aspect_ratio (21:9 through 9:21). num_images fires off 1 to 4 variations per call. Everything past those you can leave at default while you're learning: guidance_scale (3.5 default, higher means stricter prompt-following - community experience training and running local Flux Dev suggests dialing it down toward 2 tames the overcooked "AI" look, though that's Dev-specific lore and this is the hosted API, so treat it as a hypothesis to test rather than a rule), num_inference_steps (28 default), output_format (png/jpeg), safety_tolerance (0–6, BFL's own content-filter strictness slider), and prompt_upsampling (an opt-in prompt-rewriting pass).

Two outputs: image, your standard IMAGE tensor for a Preview Image or Save Image node, and status, a plain string the node fills with success/failure info. Wire status into a Show Text node while you're setting up - API-key nodes fail in stranger ways than local ones (bad key, empty account balance, a rate limit) and that string is the only place the actual reason shows up instead of just an empty image slot.

Install through ComfyUI Manager's "Install via Git URL" with the pack's GitHub link, or manually: cd into custom_nodes, git clone https://github.com/LKbaba/ComfyUI-TuZi-Flux-Kontext, then pip install -r requirements.txt (pulls in requests, python-dotenv, fal-client, httpx, httpcore - none of it heavy). Portable/embedded installs need to run pip through python_embeded\python.exe instead of a system Python. The step people skip: restart ComfyUI once after install so the .env template actually gets written, close it, open ComfyUI/custom_nodes/ComfyUI-TuZi-Flux-Kontext/.env and swap in your real TUZI_API_KEY (get one at api.tu-zi.com/panel), then restart again. Skip that two-restart dance and the node just loads red.

If the node's missing after install, do a full restart and confirm fal-client actually landed (pip list | grep fal-client - a real dependency here even though you're not touching FAL). A red node on load almost always means .env is missing or TUZI_API_KEY still holds its placeholder value. If the node loads fine but generation fails, that's your TuZi account, not the node - check balance and key validity first, and read the status output before assuming anything's broken. The pack's own changelog flags one prior bug (June 2025) where the image-to-image node specifically threw errors until you updated; it doesn't touch this text-to-image node, but on an old checkout it's a reminder to update the whole pack, not just the one you're using.