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MeltFlex CLI

Generate interiors from your terminal — or run as an MCP server

The MeltFlex CLI turns a room photo into a photorealistic redesign straight from your terminal. The same binary also runs as an MCP server so AI agents (Claude Code, Cursor) can generate through it.

It is a thin client over the MeltFlex API: you sign in to your own account and every generation is billed to your account credits. It enforces nothing itself — credits and access are governed server-side.

Input room photo
Input photo
MeltFlex redesigned room
MeltFlex result
Italian contemporary restyle
“Italian contemporary”
Japanese style restyle
“Japanese”
Terminal-native
One command generates and saves a redesigned interior to disk.
Agent-ready
Run with no arguments to expose tools to any MCP client.
Your account
Authenticates with your API key; spends your own credits.

What you can build

Furniture placement is the flagship, but meltflex generate is prompt-driven, so the one command covers the whole MeltFlex tool suite. Change the prompt (and, for material swaps, add a --ref image) and you get a different tool.

Room structure — walls, windows, flooring and fixtures — is preserved by default. For surface and fixture swaps (floors, walls, doors, windows, stairs), say explicitly what to change and what to keep. The starter prompts below already do this.

Use caseExample --prompt
Interior designRedesign in warm Scandinavian style with light oak floors and linen textiles
Layout boostRearrange the existing furniture into a more open, functional layout; keep the same pieces
Exterior designRestyle the facade in modern farmhouse style; keep the building's structure
Garden designDesign this outdoor space as a low-maintenance Mediterranean garden with gravel paths and olive trees
Walls texture (+ --ref material swatch)Change the wall finish to warm greige micro-cement; only change the walls
Floor restyle (+ --ref flooring sample)Replace the flooring with wide-plank European oak; only change the floor
Stairs designRestyle the staircase with open oak treads and a slim black steel railing; keep its position
Doors designReplace the interior doors with black-framed steel-and-glass doors; keep everything else
Windows designChange the windows to slim black aluminium frames; keep the wall openings
Kitchen designRedesign the kitchen in handleless matte-white style; keep the footprint and plumbing
Bathroom designRedesign the bathroom in warm spa-minimalism; keep the layout and plumbing
Photo to renderTurn this 3D draft / SketchUp screenshot into a photorealistic interior photograph

Preview a flooring or wall material by passing it as a reference — the same --ref mechanic used for furniture:

meltflex generate \
  --image ./living-room.jpg \
  --ref ./oak-floor-sample.jpg \
  --prompt "Replace the flooring with this wide-plank oak. Only change the floor; keep the walls, furniture and lighting unchanged." \
  --out ./new-floor.png

Two more capabilities have their own commands: meltflex video turns a still into a cinematic walkthrough, and meltflex floorplan converts a 2D floorplan into a 3D GLB model.

Install

Requires Node.js 18 or newer.

# Run on demand (no install)
npx -y meltflex-mcp <command>

# …or install globally for a shorter `meltflex` command
npm install -g meltflex-mcp

Running meltflex with no command starts the MCP server on stdio. See the MCP guide to wire it into an agent.

Authenticate

You need an active subscription (any paid plan). Once subscribed, open your account settings and click API Key under Profile:

Settings — click API Key

Then click Generate API Key. The key is shown only once — copy it immediately.

Generate API Key

Save the key once with the CLI:

# Sign in via your browser (recommended) — opens a tab, click "Authorize CLI"
meltflex auth login

# …or save an existing key manually (stored in ~/.meltflex/config.json, chmod 600)
meltflex auth mf_sk_xxxxxxxxxxxx

# Verify
meltflex whoami
# → Authenticated (key mf_sk_xxxxxx…) → https://www.meltflexai.com

Alternatively, set the MELTFLEX_API_KEY environment variable — it takes precedence over the saved file and is convenient for CI.

Commands

CommandDescription
meltflexStart the MCP server over stdio (used by AI agents).
meltflex auth loginSign in via your browser and save the key automatically (recommended).
meltflex auth <mf_sk_…>Save an existing API key to ~/.meltflex/config.json.
meltflex whoamiShow authentication status and target host.
meltflex creditsShow your credit balance and per-operation costs.
meltflex generateGenerate a redesigned interior and save it to disk.
meltflex videoAnimate a still into a cinematic walkthrough MP4 (Veo 3.1).
meltflex floorplanConvert a 2D floorplan image into a downloadable GLB 3D model.

generate

Transform a room photo. Costs 10 credits per image (lite −2, pro +5), auto-refunded on failure.

FlagRequiredDescription
-i, --imageYesSource room photo: local file path, http(s) URL, or data URL.
-p, --promptYesRedesign instruction. Room structure is preserved unless you say otherwise.
-r, --refNoReference furniture image to place in the room. Repeatable (up to 10).
-q, --qualityNoOutput resolution: 512, 1K, or 2K (sharpest). Defaults to auto.
-l, --levelNoDesign level: lite (faster, −2 cr), quick (default), or pro (most detailed, +5 cr).
--maskNoRegion edit. The image must have the area to change painted solid red; the prompt applies only there.
-n, --countNoGenerate a batch of 13 variations. Files get an index suffix (-1, -2, …).
-o, --outNoOutput file. Defaults to ./meltflex-output/interior-<timestamp>.png.
meltflex generate \
  --image ./living-room.jpg \
  --prompt "Redesign in warm Scandinavian style: light oak floor, beige linen sofa, soft daylight" \
  --out ./redesign.png

# → ✅ Saved to ./redesign.png
# → Credits used: 10

Sharper, most-detailed render — plus three variations to choose from:

meltflex generate \
  --image ./living-room.jpg \
  --prompt "Modern minimalist living room, warm oak floor, low grey sofa" \
  --quality 2K \
  --level pro \
  --count 3 \
  --out ./redesign.png

# → Generating 3 variations…
# → ✅ Saved 3 variations:
# →   • ./redesign-1.png
# →   • ./redesign-2.png
# →   • ./redesign-3.png
# → Credits used: 45

video

Animate a still image (a MeltFlex render or any interior photo) into a short cinematic walkthrough. Costs 100 credits for a 4-second clip, 150 for 8 seconds. Generation is asynchronous and typically takes 30 to 120 seconds.

FlagRequiredDescription
-i, --imageYesSource still: local file path, http(s) URL, or data URL.
-d, --durationNo4 (default, 100 credits) or 8 (150 credits).
-a, --aspectNo16:9 (default) or 9:16.
-p, --promptNoDirect the camera or mood. Defaults to a slow cinematic dolly.
-o, --outNoOutput .mp4. Defaults to ./meltflex-output/walkthrough-<timestamp>.mp4.
meltflex video \
  --image ./living-room-render.jpg \
  --duration 4 \
  --aspect 16:9 \
  --out ./walkthrough.mp4

# → Generating a 4s walkthrough… (this can take 30–120s)
# → ✅ Saved to ./walkthrough.mp4
# → Credits used: 100 • Generated in 42.28s

floorplan

Convert a flat 2D floorplan image into a downloadable GLB 3D model. Costs 10 credits. Drop the GLB straight into three.js, Blender, Unity or any glTF viewer.

FlagRequiredDescription
-i, --imageYesSource 2D floorplan (JPEG, PNG or WebP): file path, URL, or data URL.
-o, --outNoOutput .glb. Defaults to ./meltflex-output/model-<timestamp>.glb.
meltflex floorplan \
  --image ./2d-floorplan.png \
  --out ./model.glb

# → ✅ Saved to ./model.glb
# → Credits used: 10

credits

Check your balance before a batch of generations.

meltflex credits

# → MeltFlex account (you@studio.com)
# → Balance: 930 credits  (earned 1000, spent 70)
# → Cost per operation:
# →   • photo: 10
# →   • video: 100  …

Examples

Place specific furniture

Pass one or more --ref images to drop exact products into the room. The AI matches their colors, materials and proportions.

meltflex generate \
  --image https://your-cdn.com/empty-room.jpg \
  --prompt "Place these furniture items naturally in the room" \
  --ref ./sofa.jpg \
  --ref ./dining-table.jpg \
  --out ./furnished.png

Edit only one part of the room

Paint the area you want to change solid red in any image editor, then pass--mask. The prompt is applied only to the red region and the rest of the room is preserved exactly.

# First paint the area to change SOLID RED in the image (any editor),
# then --mask applies the prompt ONLY to that red region:
meltflex generate \
  --image ./room-red-marked.png \
  --prompt "Put a large green velvet armchair in the red area" \
  --mask \
  --out ./edited.png

Notes & limits

  • Subscription: API keys require an active subscription (any paid plan).
  • Credits: 10 per image (lite −2, pro +5) × the number of variations, deducted upfront and refunded automatically for any variation that fails.
  • Inputs: MeltFlex restyles an existing photo — it does not generate rooms from scratch.
  • Security: your key lives only on your machine; revoke it anytime in settings.