Image Processing MCP Server

Instructions

Implementation Reference

• tools/transform.py:286-351 (handler)

  Core handler function that loads the image, validates parameters, rotates it using PIL.Image.rotate, processes output, and returns JSON result.

  async def rotate_image(image_data: str, angle: float, expand: bool = True, fill_color: str = "#FFFFFF") -> list[TextContent]:
      """
      旋转图片
      
      Args:
          image_data: 图片数据（base64编码）
          angle: 旋转角度（度，正值为顺时针）
          expand: 是否扩展画布
          fill_color: 填充颜色
          
      Returns:
          旋转后的图片数据
      """
      try:
          # 验证参数
          if not image_data:
              raise ValidationError("图片数据不能为空")
          
          if not validate_color_hex(fill_color):
              raise ValidationError(f"无效的颜色格式: {fill_color}")
          
          # 加载图片
          image = processor.load_image(image_data)
          original_size = image.size
          
          # 转换颜色格式
          fill_rgb = tuple(int(fill_color[i:i+2], 16) for i in (1, 3, 5))
          
          # 旋转图片
          rotated_image = image.rotate(
              -angle,  # PIL中负值为顺时针
              expand=expand,
              fillcolor=fill_rgb
          )
          
          # 输出旋转后的图片
          output_info = processor.output_image(rotated_image, f"rotate_{int(angle)}deg")
          
          result = {
              "success": True,
              "message": f"图片旋转成功: {angle}度",
              "data": {
                  **output_info,
                  "original_size": original_size,
                  "rotated_size": rotated_image.size,
                  "angle": angle,
                  "expand": expand,
                  "fill_color": fill_color
              }
          }
          
          return [TextContent(type="text", text=json.dumps(result, ensure_ascii=False))]
          
      except ValidationError as e:
          error_result = {
              "success": False,
              "error": f"参数验证失败: {str(e)}"
          }
          return [TextContent(type="text", text=json.dumps(error_result, ensure_ascii=False))]
          
      except Exception as e:
          error_result = {
              "success": False,
              "error": f"图片旋转失败: {str(e)}"
          }
          return [TextContent(type="text", text=json.dumps(error_result, ensure_ascii=False))]

• main.py:206-222 (registration)

  MCP tool registration for 'rotate_image' using @mcp.tool() decorator. This wrapper function calls the core handler from tools.transform and handles errors.

  @mcp.tool()
  def rotate_image(
      image_source: Annotated[str, Field(description="图片源，可以是文件路径或base64编码的图片数据")],
      angle: Annotated[float, Field(description="旋转角度（度），正值为顺时针，负值为逆时针")],
      expand: Annotated[bool, Field(description="是否扩展画布以容纳旋转后的图片，False会裁剪", default=True)],
      fill_color: Annotated[str, Field(description="填充颜色，十六进制格式如 #FFFFFF（白色）", default="#FFFFFF")]
  ) -> str:
      """旋转图片"""
      try:
          result = safe_run_async(transform_rotate_image(image_source, angle, expand, fill_color))
          return result[0].text
      except Exception as e:
          return json.dumps({
              "success": False,
              "error": f"旋转图片失败: {str(e)}"
          }, ensure_ascii=False, indent=2)

• tools/transform.py:80-107 (schema)

  Explicit input schema definition for the rotate_image tool, returned by get_transform_tools() function.

  Tool(
      name="rotate_image",
      description="旋转图片",
      inputSchema={
          "type": "object",
          "properties": {
              "image_data": {
                  "type": "string",
                  "description": "图片数据（base64编码）"
              },
              "angle": {
                  "type": "number",
                  "description": "旋转角度（度，正值为顺时针）"
              },
              "expand": {
                  "type": "boolean",
                  "description": "是否扩展画布以容纳旋转后的图片",
                  "default": True
              },
              "fill_color": {
                  "type": "string",
                  "description": "填充颜色（十六进制格式，如#FFFFFF）",
                  "default": "#FFFFFF"
              }
          },
          "required": ["image_data", "angle"]
      }
  ),