Aseprite MCP Tools

Instructions

Implementation Reference

• aseprite_mcp/tools/drawing.py:12-64 (handler)

  The `draw_pixels` handler function, which validates inputs, builds a Lua script using `LuaBuilder`, and executes it on an Aseprite file.

  @mcp.tool()
  async def draw_pixels(filename: str, pixels: List[Dict[str, Any]]) -> str:
      """Draw pixels on the canvas with specified colors.
  
      Args:
          filename: Name of the Aseprite file to modify
          pixels: List of pixel data, each containing:
              {"x": int, "y": int, "color": str}
              where color is a hex code like "#FF0000"
      """
      try:
          # Validate inputs
          file_path = validate_file_path(filename, must_exist=True)
          
          if not pixels:
              raise ValidationError("pixels", pixels, "Pixel list cannot be empty")
          
          # Build Lua script
          builder = LuaBuilder()
          builder.add_line('local spr = app.activeSprite')
          builder.if_condition('not spr')
          builder.add_line('error("No active sprite")')
          builder.end_if()
          builder.add_line()
          
          builder.begin_transaction()
          builder.add_line('local cel = app.activeCel')
          builder.if_condition('not cel')
          builder.add_comment('If no active cel, create one')
          builder.add_line('app.activeLayer = spr.layers[1]')
          builder.add_line('app.activeFrame = spr.frames[1]')
          builder.add_line('cel = app.activeCel')
          builder.if_condition('not cel')
          builder.add_line('error("No active cel and couldn\'t create one")')
          builder.end_if()
          builder.end_if()
          builder.add_line()
          
          # Use the efficient batch pixel drawing
          builder.draw_pixels(pixels)
          builder.end_transaction()
          builder.save_sprite()
          
          # Execute script
          cmd = get_command()
          success, output = cmd.execute_lua_script(builder.build(), str(file_path))
          
          return f"Pixels drawn successfully in {file_path}"
          
      except (ValidationError, AsepriteError) as e:
          return f"Failed to draw pixels: {e}"
      except Exception as e:
          return f"Unexpected error: {e}"