Draft on Grok Imagine, finish on Seedance 2.5: two calls, one prompt

Send the idea to grok-imagine-video-1.5 first: a 10-second draft is $0.125. When the draft shows the right motion and framing, send the same prompt to seedance-2.5 at 1080p for $14.22. The two are separate jobs on the same /v1/videos endpoint; only model and resolution change.

The script

It submits the draft, waits, and only sends the expensive call if you answer yes. Poll polling_url; the draft is done when status is completed.

import os, time, requests
H = {"Authorization": "Bearer " + os.environ["SUME_API_KEY"], "Content-Type": "application/json"}
U = "https://api.sume.com/v1/videos"
PROMPT = "A chef flips a pancake in slow motion, steam rising"

def run(model, **kw):
    r = requests.post(U, headers=H, json={"model": model, "prompt": PROMPT, "duration": 10, **kw})
    r.raise_for_status()
    url = r.json()["polling_url"]
    while True:
        j = requests.get(url, headers=H).json()
        if j["status"] in ("completed", "failed", "cancelled"):
            return j
        time.sleep(30)

draft = run("grok-imagine-video-1.5")
print(draft["status"], draft.get("unsigned_urls"))
if draft["status"] == "completed" and input("Finish? [y/N] ") == "y":
    final = run("seedance-2.5", resolution="1080p")
    print(final["status"], final.get("usage"))

What it costs

The draft is a rounding error next to the final.

Things to know

• Sume reserves the full price at submit; a balance shortfall returns 402 insufficient_credits.
• Do not reuse the same Idempotency-Key for draft and final: a replay returns the first job.
• Different models read prompts differently, so treat the draft as a check of the idea, not a preview of the final.

Extending the script

Once the single-pair flow works, read prompts from a file and store each draft's job id. A reviewer then picks which ids get a final, and only those prompts go to the second call. The second call can also use a webhook: add an HTTPS callback_url to the body and Sume POSTs a signed envelope when the job reaches a terminal state, so you stop polling.

Sume reserves the full price at submit, so the number in the table is also the amount that must be free in the balance when you send the request. If it is not, the call fails with 402 insufficient_credits before any provider work starts.