aseprite-mcp

MCP server for safe local automation of Aseprite. It exposes a focused set of Model Context Protocol tools that create, inspect, edit, save, and export pixel art documents through the official Aseprite CLI and controlled Lua scripts.

The current implementation is a working MVP for the prompt's Phase 3. It intentionally avoids generic run_lua, execute_command, or shell tools.

Requirements

• Node.js 20+

• Aseprite installed locally

• A client that can launch MCP servers over stdio

Official references used for this implementation:

• Aseprite CLI: https://www.aseprite.org/docs/cli/

• Aseprite Lua API: https://www.aseprite.org/api/

• MCP TypeScript SDK: https://github.com/modelcontextprotocol/typescript-sdk

• MCP resources spec: https://modelcontextprotocol.io/specification/2025-06-18/server/resources

Install

npm install
npm run build

Configure

Copy the example config if you want file-based configuration:

cp aseprite-mcp.config.example.json aseprite-mcp.config.json

On Windows PowerShell:

$env:ASEPRITE_PATH = "C:\Program Files\Aseprite\Aseprite.exe"
$env:ASEPRITE_MCP_ALLOWED_DIRECTORIES = "C:\Users\Usuario\Documents\MAX\PROYECTOS"

Supported environment variables:

• ASEPRITE_PATH

• ASEPRITE_MCP_ALLOWED_DIRECTORIES

• ASEPRITE_MCP_TEMP_DIRECTORY

• ASEPRITE_MCP_MAX_WIDTH

• ASEPRITE_MCP_MAX_HEIGHT

• ASEPRITE_MCP_MAX_FRAMES

• ASEPRITE_MCP_PROCESS_TIMEOUT

• ASEPRITE_MCP_ALLOW_OVERWRITE

• ASEPRITE_MCP_LOG_LEVEL

Run

npm run build
npm start

The server uses stdio, so it is meant to be launched by an MCP client.

Codex MCP Example

See examples/codex.mcp.json.

{
  "mcpServers": {
    "aseprite": {
      "command": "node",
      "args": ["C:/absolute/path/to/aseprite-mcp/dist/index.js"],
      "env": {
        "ASEPRITE_PATH": "C:/Program Files/Aseprite/Aseprite.exe",
        "ASEPRITE_MCP_ALLOWED_DIRECTORIES": "C:/Users/Usuario/Documents/MAX/PROYECTOS"
      }
    }
  }
}

Claude Desktop Example

See examples/claude-desktop.mcp.json.

Implemented Tools

• aseprite_create_sprite

• aseprite_get_document_info

• aseprite_list_layers

• aseprite_list_frames

• aseprite_set_pixels

• aseprite_fill_region

• aseprite_clear_region

• aseprite_draw_line

• aseprite_draw_rectangle

• aseprite_create_frame

• aseprite_create_tag

• aseprite_get_animation_info

• aseprite_set_frame_duration

• aseprite_set_tag_range

• aseprite_set_tag_direction

• aseprite_get_palette

• aseprite_export_palette

• aseprite_create_dual_grid_tileset

• aseprite_save_document

• aseprite_export_png

• aseprite_export_spritesheet

Resources

• aseprite://capabilities

• aseprite://config

• aseprite://runtime

Prompts

• create-pixel-character

• prepare-spritesheet-for-unity

Example Calls

Create a 32x32 sprite:

{
  "width": 32,
  "height": 32,
  "colorMode": "rgb",
  "frameCount": 1,
  "frameDurationMs": 100,
  "outputPath": "examples/output/player.aseprite",
  "overwrite": true
}

Draw several pixels:

{
  "filePath": "examples/output/player.aseprite",
  "frameIndex": 1,
  "layerIndex": 1,
  "pixels": [
    { "x": 1, "y": 2, "color": "#FF0000FF" },
    { "x": 2, "y": 2, "color": "#00FF00FF" }
  ],
  "createBackup": true
}

Create four frames:

{
  "width": 32,
  "height": 32,
  "frameCount": 4,
  "frameDurationMs": 120,
  "outputPath": "examples/output/player.aseprite",
  "overwrite": true
}

Create the idle tag:

{
  "filePath": "examples/output/player.aseprite",
  "name": "idle",
  "fromFrame": 1,
  "toFrame": 4,
  "direction": "ping-pong"
}

Export a spritesheet:

{
  "filePath": "examples/output/player.aseprite",
  "sheetPath": "examples/output/player.png",
  "dataPath": "examples/output/player.json",
  "sheetType": "horizontal",
  "listLayers": true,
  "listTags": true,
  "overwrite": true
}

Create a dual-grid tileset:

{
  "outputPath": "examples/output/dual-grid-grass.aseprite",
  "metadataPath": "examples/output/dual-grid-grass.json",
  "tileSize": 16,
  "columns": 4,
  "layoutPreset": "template",
  "referenceStencil": [
    "00011000",
    "10011111",
    "10011111",
    "01111110",
    "01111110",
    "00000110",
    "00000110",
    "00110000"
  ],
  "terrainColor": "#49AD52FF",
  "backgroundColor": "#00000000",
  "gridColor": "#FF55D6FF",
  "guideMode": "none",
  "labelMode": "quadrants",
  "styleMode": "basic",
  "requireUniqueTiles": true,
  "overwrite": true
}

The default template layout follows a dual-grid stencil with 16 unique tile patterns. Material pixels are placed according to a pixel-level template grid, not by row-major binary mask order. referenceStencil is optional; when provided, it must be a rectangular 0/1 matrix whose width is divisible by columns and whose height is divisible by the tileset rows. requireUniqueTiles rejects repeated patterns. labelMode: "quadrants" overlays G for ground and V for void in each tile quadrant, useful for debugging the template before art styling. Use styleMode: "grass" to render styled grass details instead of plain terrain fills. Use layoutPreset: "bitmask" only when you need the direct NW=1, NE=2, SE=4, SW=8 quadrant map. The metadata file includes tile rectangles, per-tile stencil patterns, pattern resolution, and quadrant summaries for engine-side lookup.

Query the palette:

Use aseprite_get_document_info; the document.palette array contains palette entries.

Generate a preview:

Use aseprite_export_png:

{
  "filePath": "examples/output/player.aseprite",
  "outputPath": "examples/output/player-preview.png",
  "overwrite": true
}

Modify an existing file safely:

{
  "filePath": "examples/output/player.aseprite",
  "outputPath": "examples/output/player-edited.aseprite",
  "pixels": [
    { "x": 10, "y": 10, "color": { "r": 255, "g": 255, "b": 255, "a": 255 } }
  ],
  "createBackup": true,
  "overwrite": true
}

Security Model

• All paths are resolved against the server working directory.

• Reads and writes are restricted to configured allowed directories.

• Path traversal and unsupported extensions are rejected.

• Aseprite is launched with argument arrays, not shell command strings.

• Lua is generated by the server and selected by operation name.

• Clients cannot send arbitrary Lua or shell commands.

• Writes can require explicit overwrite.

• Destructive operations can create backups.

• Per-file locks serialize writes to the same destination.

• Processes have timeouts and output size limits.

Tests

npm run build
npm test

Current verified result:

• TypeScript build passes.

• 5 test files pass.

• 11 tests pass.

The integration smoke test checks discovery without requiring Aseprite. Full real-file tests require ASEPRITE_PATH.

Known Aseprite Limitations

• CLI export is strong for conversion and spritesheets, but many document edits require Lua.

• --sheet overwrites output files, so this server validates overwrite before invoking it.

• Some Lua standard library operations can be permission-sensitive in Aseprite; this MVP avoids client-supplied Lua and passes operation payload through script parameters.

• Spritesheet export options are limited to documented CLI flags currently wired in command-builder.ts.

• Additional tileset systems, region transforms, palette mutation tools, and high-level deterministic generators are not implemented yet.

Pending Tools

Next priority groups:

• Sequence duplication and animation preview export

• Palette mutation/import

• Region ellipse/flood-fill/move/flip/rotate

• Additional tileset creation systems and metadata

• High-level deterministic templates for 16/32px characters, enemies, objects, and UI

Complete Animation Flow

See examples/create-animation.json for a complete sequence:

1. Create a 32x32 four-frame document.

2. Draw a compact set of pixels.

3. Create an idle ping-pong tag.

4. Export a horizontal spritesheet and JSON metadata.