lassetier-mcp

MCP server for Lassetier — generate and convert game assets (isometric, top-down, platformer, pixel art) directly from AI agents like Claude Code.

The server is a thin client of the public Lassetier REST API: every generation is billed in Lassetier credits (1 credit = $0.01 USD, ~25 credits per asset) and every tool response reports the exact cost and remaining balance.

Setup

1. Create an API key at https://lassetier.com/dashboard/settings/api-keys (shown once — store it safely).
2. Add the server to Claude Code:

claude mcp add --env LASSETIER_API_KEY=lat_live_xxx --transport stdio lassetier -- npx -y lassetier-mcp

That's it. Open a new Claude Code session and the lassetier tools are available.

Project-scoped .mcp.json (shared with your team — put the key in your shell env instead of the file):

{
  "mcpServers": {
    "lassetier": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "lassetier-mcp"],
      "env": { "LASSETIER_API_KEY": "${LASSETIER_API_KEY}" }
    }
  }
}

Environment variables

| Variable | Required | Description | | --- | --- | --- | | LASSETIER_API_KEY | yes | Your lat_live_… key | | LASSETIER_API_URL | no | API base URL (default https://lassetier.com/api/v1) |

Tools

| Tool | Cost | Description | | --- | --- | --- | | generate_asset | ~25 credits | One asset from a text prompt; saves the PNG locally if output_path is given | | convert_image | ~25 credits | Converts a local image into a game asset, faithful to the source | | generate_batch | ~25 × n | Up to 20 assets of the same style into a folder (tilesets!) | | animate_asset | free | Procedural animation preset (float, pulse, spin, sway, blink, shake, bob) on an existing asset — 0 credits, instant | | generate_animation | ~25-100 credits | AI walk/idle/attack/effect animation (method routed internally, failures auto-refunded) | | pack_spritesheet | free | Packs local images or library assets into an engine-ready spritesheet + atlas (Phaser/PixiJS, Godot 4, Unity, generic) | | search_library | free | Search your saved assets + CC0 packs | | download_library_asset | free | Download a library asset into the project | | list_styles | free | The 6 styles with descriptions | | get_credits | free | Balance and price per image, in credits |

Styles: isometric, isometric_pixel, topdown, platformer, pixel32, pixel64.

Safety by design

• Files are only written inside the current working directory — absolute or ../ escapes are refused.
• An existing file is never overwritten unless the agent passes overwrite: true.
• Output paths are validated before any credits are spent.
• Insufficient balance returns the exact shortfall and the purchase URL; failed generations are automatically refunded.

Example session

You: Génère un tileset isométrique de 6 routes et place-le dans assets/tiles/.

Claude Code calls generate_batch:

{
  "style": "isometric",
  "output_dir": "assets/tiles",
  "prompts": [
    { "prompt": "a straight asphalt road tile", "filename": "road-straight.png" },
    { "prompt": "a 90 degree asphalt road turn tile", "filename": "road-turn.png" },
    { "prompt": "a T-intersection asphalt road tile", "filename": "road-t.png" },
    { "prompt": "a 4-way asphalt road crossing tile", "filename": "road-cross.png" },
    { "prompt": "an asphalt road tile with a pedestrian crossing", "filename": "road-crosswalk.png" },
    { "prompt": "a dead-end asphalt road tile with a roundabout", "filename": "road-end.png" }
]
}

Result:

Batch: 6 assets in style "isometric" — estimated 150 credits ($1.50) (balance before: 800 credits ($8.00)).
✓ assets/tiles/road-straight.png (503 KB)
✓ assets/tiles/road-turn.png (153 KB)
✓ assets/tiles/road-t.png (210 KB)
✓ assets/tiles/road-cross.png (245 KB)
✓ assets/tiles/road-crosswalk.png (198 KB)
✓ assets/tiles/road-end.png (176 KB)
Done: 6/6 assets, total 150 credits ($1.50). Remaining balance: 650 credits ($6.50).

All tiles share the same camera angle, lighting and style — ready to drop into your game.

Complete workflow: generate, then pack (free)

The natural chain — ask once:

You: Generate 6 isometric road tiles and pack them into a Phaser spritesheet in assets/tiles/.

Claude Code calls generate_batch (above), then pack_spritesheet:

{
  "image_paths": [
    "assets/tiles/road-straight.png",
    "assets/tiles/road-turn.png",
    "assets/tiles/road-t.png",
    "assets/tiles/road-cross.png",
    "assets/tiles/road-crosswalk.png",
    "assets/tiles/road-end.png"
  ],
  "engine": "phaser",
  "output_dir": "assets/tiles",
  "mode": "grid"
}

Result:

Spritesheet ready — FREE (0 credits, 6 images).
✓ assets/tiles/sheet-0.png
✓ assets/tiles/atlas.json
✓ assets/tiles/INSTRUCTIONS.txt
✓ assets/tiles/stats.json
See INSTRUCTIONS.txt for the phaser import steps.

Packing is always free (no AI involved): trim with correct offsets, MaxRects packing, 1 px edge extrusion against texture bleeding, duplicate detection, multi-page when needed. Engines: phaser (also PixiJS), godot (Godot 4 — .tpsheet plugin + native .tres), unity (.tpsheet for TexturePacker Importer), generic (JSON + CSS).

Animation workflow: generate → animate → pack

You: Generate a gold coin asset, make it spin, and pack it into a Phaser spritesheet.

Claude Code chains three tools:

1. generate_asset — { "prompt": "a shiny gold coin", "style": "isometric", "output_path": "assets/coin.png" } (~25 credits)
2. animate_asset — { "asset_id": "<conversion id from step 1>", "preset": "spin", "output_dir": "assets/coin-spin" } (free)
3. pack_spritesheet — { "image_paths": ["assets/coin-spin/frame-000.png", …], "engine": "phaser", "output_dir": "assets/coin-spin", "mode": "grid" } (free)

Result: sheet-0.png + atlas.json ready for this.anims.create() — total cost 25 credits, the animation itself was free.

CLI

The package also ships a lassetier command:

npm install -g lassetier-mcp
lassetier auth lat_live_xxx        # saved to ~/.lassetier/config.json (600), verified

lassetier generate "un baril de bois" --style iso --out ./assets/barrel.png
lassetier convert ./photo.jpg --style iso-pixel --out ./assets/
lassetier batch ./prompts.txt --style iso --out ./assets/   # one prompt per line, # = comment
lassetier search "medieval house" --game-type iso
lassetier credits

• Style aliases: iso → isometric, iso-pixel → isometric_pixel, top-down → topdown.
• Batches over 5 images ask for confirmation with the cost estimate (14 images × 25 crédits ≈ 350 credits ($3.50). Continuer ? [o/N]) — bypass with --yes for CI.
• --json on every command for programmatic use (human noise stays on stderr).
• Exit codes: 0 success, 1 error, 2 insufficient credits.
• --out accepts a file or a directory; existing files are never overwritten without --overwrite.

Development

npm install
npm run build
# test locally against the server:
claude mcp add --env LASSETIER_API_KEY=lat_live_xxx --transport stdio lassetier -- node ./dist/index.js

License

MIT — the Lassetier API itself is a paid service (pay-as-you-go credits, no subscription).