Image Processing MCP Server

Instructions

Implementation Reference

• tools/filters.py:589-658 (handler)

  Core handler function implementing the sepia filter. Loads image, applies pixel-by-pixel color transformation using sepia tone matrix (coefficients for R,G,B channels), clamps values to 0-255, and returns processed image data via ImageProcessor.

  async def apply_sepia(image_data: str) -> list[TextContent]:
      """
      应用复古棕褐色滤镜
      
      Args:
          image_data: 图片数据（base64编码）
          
      Returns:
          应用滤镜后的图片数据
      """
      try:
          # 验证参数
          if not image_data:
              raise ValidationError("图片数据不能为空")
          
          # 加载图片
          image = processor.load_image(image_data)
          
          # 转换为RGB模式
          if image.mode != 'RGB':
              image = image.convert('RGB')
          
          # 应用棕褐色滤镜
          pixels = image.load()
          width, height = image.size
          
          for y in range(height):
              for x in range(width):
                  r, g, b = pixels[x, y]
                  
                  # 棕褐色变换公式
                  tr = int(0.393 * r + 0.769 * g + 0.189 * b)
                  tg = int(0.349 * r + 0.686 * g + 0.168 * b)
                  tb = int(0.272 * r + 0.534 * g + 0.131 * b)
                  
                  # 确保值在0-255范围内
                  tr = min(255, tr)
                  tg = min(255, tg)
                  tb = min(255, tb)
                  
                  pixels[x, y] = (tr, tg, tb)
          
          # 输出处理后的图片
          output_info = processor.output_image(image, "sepia")
          
          result = {
              "success": True,
              "message": "复古棕褐色滤镜应用成功",
              "data": {
                  **output_info,
                  "filter_type": "sepia",
                  "size": image.size
              }
          }
          
          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"复古棕褐色滤镜应用失败: {str(e)}"
          }
          return [TextContent(type="text", text=json.dumps(error_result, ensure_ascii=False))]

• main.py:354-367 (registration)

  MCP tool registration using @mcp.tool() decorator. Defines tool schema via Annotated Field (image_source: str), description, and wraps the execution of the core handler from filters.py using safe_run_async.

  @mcp.tool()
  def apply_sepia(
      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")]
  ) -> str:
      """应用复古棕褐色滤镜"""
      try:
          result = safe_run_async(filters_apply_sepia(image_source))
          return result[0].text
      except Exception as e:
          return json.dumps({
              "success": False,
              "error": f"应用复古滤镜失败: {str(e)}"
          }, ensure_ascii=False, indent=2)

• tools/filters.py:149-162 (schema)

  Explicit JSON schema definition for the apply_sepia tool input, specifying required 'image_data' string parameter. Matches the MCP tool signature.

  Tool(
      name="apply_sepia",
      description="应用复古棕褐色滤镜",
      inputSchema={
          "type": "object",
          "properties": {
              "image_data": {
                  "type": "string",
                  "description": "图片数据（base64编码）"
              }
          },
          "required": ["image_data"]
      }
  ),