Open the studio

Your character drifted.
That retake cost you $1.52.

AI video models forget what your character looks like — a tail changes colour mid-run, a leap hovers in mid-air, a prop blinks when it shouldn't. You find out after you've paid. Character Studio is a front end for fal.ai that catches those failures before you spend, using guardrails taken from a real production.

Bring your own fal.ai key · nothing to install · your key never leaves your browser

Where the rules came from

Every guardrail here is a receipt.

These aren't best practices copied off a forum. Each one is a specific failure from producing an animated short — found by auditing frames, paid for in real generations, then written down so it never happens twice.

The floating leap
A character leapt over another and hung in mid-air for a full second at the apex. Two takes wasted before the physics contract fixed it — the next attempt measured a gravity-true 0.22 second apex.
The balloon dog
A character visibly inflated as it ran toward camera, reading as a balloon rather than an approach. Fixed by a size-constancy contract plus routing the exit past the lens.
Identity decay
Five takes in a row, across two different models, grew defects in the final second as the character left frame — a tail gaining markings that belong to a different character. Reference anchoring eliminated it: 33 of 33 exit frames clean.
The blinking prop
A stuffed toy blinked — twice — because one model animates any face that fills the frame, even an inanimate one. Negative prompts didn't stop it. Routing the shot to a different model did.
Trait bleed
In three of three two-character close-ups, one character's markings appeared on the other. Writing "clean muzzle" in the prompt did not prevent it. Only a zoom audit before spending caught it.
The pattern behind all of it: fail at image prices, not video prices. A still costs about four cents. A video take costs up to $1.52. Every rule in this tool exists to move a failure from the second column into the first.
What it actually does

It writes the prompt properly, then refuses to let you waste money.

Identity blocks, verbatim

Write your character's description once. It's pasted byte-for-byte into every prompt — the single discipline that stops a character drifting between shots.

Camera-first assembly

Builds the prompt in the order models actually respond to: one camera instruction first, continuous-shot lock, identity, ordered action beats, exclusions, style lock.

A linter that blocks

Breed names, corrupted text, unfilled template slots, an altered identity block — the Generate button stays disabled until they're gone.

Cost before you spend

Every take is priced before you commit, and logged after, so you can see where your credits went.

Physics contracts

Proven prose for the hard shots — ballistic arcs, size constancy, prop custody, sleep integrity — the language that made those failures stop.

A two-strike breaker

Try the same shot twice and fail? It blocks the third. A repeated failure is structural — change the model or the staging, don't pay to watch it again.

Questions

The practical bits.

Do I need a fal.ai account?

Yes — that's the point. You bring your own key, so you pay fal directly at cost with no markup from us, and we never touch your generation spend. Your key is stored only in your own browser and sent only to fal.ai.

Does this generate video itself?

It drives fal.ai's models — Kling, Seedance, Seedream, Flux — from your browser. The tool's job is composing the prompt correctly, routing to the right model, blocking bad takes before they cost you, and showing the result.

Is my work stored anywhere?

No. There's no account and no server holding your data. Your characters, settings and ledger live in your browser's local storage, and you can export the whole project as a single file to move it to another device.

Will this work for my characters, not just dogs?

Yes. The rules are about how video models fail — identity drift, invented accessories, treadmilling, floating physics — not about any particular character. You define your own cast and the system applies to them.

What does it cost?

The studio is free to use — no signup, no account. You only ever pay fal.ai directly for the generations you run, at their price, with your own key.