You already know the catalog. This page is about the other half — making sure the model you named is the one that ran, and knowing what to do when it wasn't. It's all plain conversation; there's nothing to configure and no mode to switch on.
Mention the model in your request and it gets used. No special syntax.
Make a brass compass on weathered oak — use flux-schnell. Animate this frame with kling-o3-i2v, five seconds.If you're not sure of a name, ask before you render — it's free and instant:
Which video models can I use, and what do they cost?And when you don't care which model runs, say nothing about models. You'll get the default fast path, with no model chatter in the reply.
Whenever you name a model, the reply ends by telling you which one did the work. Three things you might see:
Nothing to do. That's a confirmation, not a warning.
The reason is always there. The next section covers what each one means.
No mention of models at all. Naming one is what opts you into the extra detail.
Three of these are the network protecting you. Only the first one is your typo.
| What you'll be told | What it means | What to say next |
|---|---|---|
| not a registered model name | That name isn't live here, so the closest available model was used instead. | "List the video models" — then use the exact name from that list. |
| that model is temporarily disabled | It's known to be broken and charges you even when it fails, so a working replacement ran. | Nothing. You were kept from paying for a dead model. |
| no source frame | You named an image-to-video model but didn't give it a starting image. That request gets rejected, so its text-to-video sibling ran. | Give it a starting frame — "animate this image with …" — and your pick will hold. |
| the model you asked for failed | Your pick went first, hit an error it could recover from, and a similar model was tried so you'd still get something. | "Try that again", or demand exactness (next section) to see the real failure. |
An unfamiliar name isn't rejected — it's matched to the closest live model. That's deliberate: it rescues typos and keeps long pipelines from dying on a spelling slip. The cost is that a wrong name gets you a wrong model rather than an error. Real cases:
| You ask for | You get | Why it stings |
|---|---|---|
| sora-2 | flux-dev | You wanted video and got a still image. |
| runway-gen4 | flux-dev | Same — no video model matched that name. |
| wan-2.5 | wan-22-i2v-lora | A shared name prefix lands you on an unrelated image-to-video style model. |
Sometimes a substitute is worse than nothing — you're comparing two models, or a client signed off on one specifically. Say so, plainly:
Use exactly kling-o3-i2v. Don't substitute — fail instead. Render this on flux-pro only. No fallbacks.Phrased like that, your name goes straight through untouched. If that model isn't available, you get a clear failure instead of a quiet stand-in.
So: reach for exactness when identity of the model matters more than convenience, and stay on the normal path the rest of the time.
| When you want to… | Say something like |
|---|---|
| Use a specific model | "…using kling-o3-i2v" |
| Insist on it, no substitutes | "use exactly kling-o3-i2v — fail rather than substitute" |
| See what's available | "which image models can I use?" |
| Check a price first | "what does kling-o3-i2v cost for 5 seconds?" |
| Understand one model properly | "tell me about kling-o3-i2v — inputs, limits, price" |
| Go fast, or go premium, without picking | "make it fast" · "do this one in high quality" |
| Keep an image-to-video model on your prompt | give it a starting frame — "animate this image…" |
| Know what a finished render used | "what did that run on?" |
| See your spending | "what have I spent today?" |
| Put a ceiling on it | "cap my spend at $5 a day" |
Everything above is also machine-readable. The reply carries the model that ran, the model you asked for, and — only when those differ — a note holding both names, the reason, and the underlying error. Long-running jobs report the same three when you check back on them.