Grok Imagine Video 1.5: Runway's listing vs Sume's catalog row

On Sume, grok-imagine-video-1.5 is an image-to-video row only: it needs image_url or first_frame_url, takes 480p or 720p, runs 4 to 15 seconds, and has no audio, end-frame or reference support in the catalog. Do not assume another vendor's listing carries over. Runway's changelog entry of Aug 13, 2026 says Grok Imagine 1.5 is available in Runway MCP with text-to-video and image-to-video, native audio, 1 to 15 second clips and up to 1080p; that is Runway's surface, not Sume's row.

Side by side

The Sume side is read from the Video Router docs; the Runway side is only what the vendor's changelog page states (the entry names Runway MCP, not a Runway API endpoint), so verify there before building.

What this means for a plan

If your Grok workflow starts from a prompt alone, the Sume row will reject it: add a first frame, which you can make with an image model on Sume. If you need an end frame, use a row that lists end_frame, such as wan-3.0 or minimax-h3. If you need synchronized audio, pick a row with the audio capability and check the flag in the catalog first.

• Prompt only: use a text-to-video row, not this one.
• Photo to motion: this row fits.
• Two keyframes: use another row.
• Pricing: every Video Router row bills at provider list times 1.25.

Read the row yourself

The catalog is the source of truth and updates without a blog post. Fetch the row and look at capabilities and constraints before sending money-bearing requests.

curl -s https://api.sume.com/v1/video-router/models/grok-imagine-video-1.5 \
  -H "Authorization: Bearer $SUME_API_KEY"

Sources

The Sume behavior is documented on the Video Router page and the Video generation page; failed requests release their reserve per generation admission. For the vendor side, read the Runway changelog directly at the source link below.