The states a slide moves through as the shared media engine is hosted per-slide — from an empty production, through the model-gate, composing & generating, the resolved key-scope, the composedPromptSnapshot pinned at deliver, and finally a carousel delivered to its ad. A carousel is a flat, ordered set of single-image slides — no per-resource checklist.
Saved
a Empty → storyboard Seed
A brand-new carousel has no slides and no planner plan. The studio offers a Draft storyboard CTA — AI seeds the slide count, an image prompt per slide, and a card headline (headlines flow to the ad, not the image). Once seeded, each slide becomes its own engine host. You can also add slides one at a time and write each prompt yourself.
Draft the storyboard with AI
No slides yet, and no planner plan to inherit. From the carousel brief, AI proposes the slide count, an image prompt for each slide, and a card headline — then each slide becomes a deep engine host you compose & generate.
AI seeds slides only when there's no planner plan — otherwise the plan's slides flow straight in.
What AI proposes (preview)
Slide 1 · Hook image
Sun-drenched flat-lay of the summer collection on warm golden sand, vivid coral tones, 4:5.
Lifestyle shot, model wearing the collection at golden hour by the coast.
→ card headline: “Loved by 12k+ shoppers”
Slide 4 · CTA image
Bold end-card composition over a warm gradient, generous space for the lockup.
→ card headline: “Ends Sunday — shop now”
b Pick a model first Gated
Each slide owns its own provider/model (per-slide override) — and until this slide has a committed model, the engine card is gated: the composed prompt is disabled and the auto-preview does not fire model-less. Pick a Higgsfield model for this slide to unlock composing.
Shared media engine · slide-scoped
Media provider
higgsfield
On-platform slide-image generation is Higgsfield-only — google-flow stays in the manual / DIY path.
slide 4 · resolveMediaProviderKey
Higgsfield model — pick one to unlock this slide's prompt
Select a model for this slide…
Composed image prompt — slide 4
Pick a model for this slide first
This slide has no committed model yet, so the composed prompt stays disabled and the auto-preview does not fire model-less. Choose a Higgsfield model above to compose & refine this slide's image prompt. Each slide carries its own picker + snapshot.
Preview — disabled until a model is picked
The gate is per-slide: slide 1's committed model does not unlock slide 4. Compose & refine use the free text path; Generate spends a media credit via resolveMediaProviderKey.
c Composing / Generating In-flight
Two distinct in-flight states. Composing (free text path) shimmers the prompt while your AI provider drafts/refines it. Generating (media credit) shows the “Generating 3 candidates…” banner while Higgsfield renders the slide image from the pinned snapshot.
Composing promptslide 2 · free text path
Composed image prompt — slide 2
Your AI provider is composing this slide's prompt — no media credit spent.
Composing runs on the cheap text path (your AI key / platform key). The result lands in the editable textarea and is what Generate pins.
Generating 3 candidates…
Slide 2 · Nano Banana Pro · 4:5 · running the prompt pinned to slide 2's snapshot
media credit
72%
61%
58%
This is the only step that spends a media credit — Higgsfield resolves via resolveMediaProviderKey. The 3-up candidate grid fills in as each candidate resolves.
d Resolved scope Key resolution
After composing, the engine reports which key composed the prompt — the .ebadge.scope on each slide's panel. The platform text key (capped) is the default; a tenant text BYOK overrides it and bypasses the cap. This is the text-path scope — separate from the Higgsfield media connector used at Generate.
composed on platform key
Default — the slide's prompt was composed with the platform MiniMax text key (credit-capped). Shown when the tenant hasn't set a text BYOK. Slide 1 here used the platform key.
composed on your key
Override — the tenant's own text AI key (BYOK) composed the prompt, bypassing the platform credit cap (metering-bypass). Slides 2–4 here used your key.
slide 2 · resolveMediaProviderKey
The media scope — for completeness. Generate always resolves the tenant's Higgsfield connector (media is connector/BYOK-only), independent of which text key composed the prompt.
Each slide resolves its scope independently when its panel mounts — one carousel can show platform key on some slides and your key on others.
e Pinned prompt on deliver Snapshot
At deliver, each slide shows its selected image alongside a read-only as-generated prompt — the composedPromptSnapshot pinned when Generate ran. Later edits to a slide's live prompt don't rewrite history: the snapshot records exactly what produced the delivered image.
Sun-drenched hero flat-lay: summer linen collection on warm golden sand at golden hour, low raking light, vivid coral-and-teal palette, generous negative space upper third for headline, brand logo bottom-right, photoreal 4:5.
Close-up hero product shot of the summer linen shirt, soft diffused daylight, breezy fabric texture, warm coral tones, shallow depth of field, product razor-sharp, clean background, 4:5.
composed on your key
The snapshot is per-slide and immutable once generated — it's not the slide's current editable prompt. Re-generating a slide writes a new snapshot for its new image.
f Delivered Done
Every slide has a selected image → the carousel delivers to its ad as an ordered set of cards. Card headlines & links live on the ad (set in Ad · card copy), not baked into the slide images.
Carousel delivered to ad
All 4 slides have a selected image · delivered to Ad “Summer Sale” → Ad set “Warm — Sales” as 4 ordered cards.
Meta Ads
1 · Hook
2 · Benefit
3 · Proof
4 · CTA
Each slide carried its own pinned snapshot into delivery.