Aseprite MCP Tools

Instructions

Implementation Reference

• aseprite_mcp/tools/drawing.py:66-109 (handler)

  The draw_line handler function, which validates inputs, generates a Lua script using LuaBuilder, and executes it via Aseprite.

  @mcp.tool()
  async def draw_line(filename: str, x1: int, y1: int, x2: int, y2: int, color: str = "#000000", thickness: int = 1) -> str:
      """Draw a line on the canvas.
  
      Args:
          filename: Name of the Aseprite file to modify
          x1: Starting x coordinate
          y1: Starting y coordinate
          x2: Ending x coordinate
          y2: Ending y coordinate
          color: Hex color code (default: "#000000")
          thickness: Line thickness in pixels (default: 1)
      """
      try:
          # Validate inputs
          file_path = validate_file_path(filename, must_exist=True)
          color = validate_color(color)
          
          if thickness < 1:
              raise ValidationError("thickness", thickness, "Thickness must be at least 1")
          
          # 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.draw_line(x1, y1, x2, y2, color, thickness)
          builder.end_transaction()
          builder.save_sprite()
          
          # Execute script
          cmd = get_command()
          success, output = cmd.execute_lua_script(builder.build(), str(file_path))
          
          return f"Line drawn successfully in {file_path}"
          
      except (ValidationError, AsepriteError) as e:
          return f"Failed to draw line: {e}"
      except Exception as e:
          return f"Unexpected error: {e}"