Grok Imagine image edit limit: xAI 5 sources, Sume catalog

xAI's release notes say image editing now accepts up to 5 source images per request, up from 3. On Sume, Grok Imagine is the edit-capable x-ai/grok-image row with n capped at 1, and the input_references limit comes from the model's descriptor in GET /v1/images/models, where edit-capable models other than GPT Image 2.5 get a ceiling of 10.

xAI's figure is from its release notes; Sume's from the Image API docs and catalog code, read 2026-09-30. Sume does not document how many sources the Grok provider accepts beyond that descriptor, so test before relying on a high count.

What changed on xAI's side?

The same release notes entry lists five reference images for editing (was 3), plus new aspect ratios 21:9 and 5:2. The notes link it to multi-image editing in xAI's own docs.

What does Sume advertise for Grok?

How do I find the real limit?

The docs say to read the input_references descriptor per model: text-only models show {"min": 0, "max": 0} and reject references. Too many references returns a 400 naming the maximum. Compare with GPT Image's 16 references.

What if I send a parameter Grok does not list?

It is rejected with 400 unsupported_parameter rather than dropped. Since n is capped at 1, loop your calls for multiple variants; see the n-parameter post.