Image Processing MCP Server

Instructions

Implementation Reference

• tools/color_adjust.py:161-208 (handler)

  Core handler function that loads the image, applies brightness adjustment using PIL ImageEnhance.Brightness, processes output, and returns JSON result.

  async def adjust_brightness(image_source: str, factor: float) -> list[TextContent]:
      """
      调整图片亮度
      
      Args:
          image_source: 图片数据（base64编码）或文件路径
          factor: 亮度调整因子（0.0-2.0）
          
      Returns:
          调整后的图片数据
      """
      try:
          # 验证参数
          if not image_source:
              raise ValidationError("图片数据或路径不能为空")
          
          if not validate_numeric_range(factor, 0.0, 2.0):
              raise ValidationError(f"亮度因子必须在0.0-2.0范围内: {factor}")
          
          # 加载图片
          image = processor.load_image(image_source)
          
          # 调整亮度
          enhancer = ImageEnhance.Brightness(image)
          enhanced_image = enhancer.enhance(factor)
          
          # 输出处理后的图片
          output_info = processor.output_image(enhanced_image, "brightness")
          
          result = {
              "success": True,
              "message": f"亮度调整成功: 因子 {factor}",
              "data": {
                  **output_info,
                  "brightness_factor": factor,
                  "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))]

• main.py:384-398 (registration)

  Registers the 'adjust_brightness' tool with FastMCP server using @mcp.tool decorator, defines input parameters with descriptions, and delegates execution to the imported handler via safe_run_async.

  @mcp.tool()
  def adjust_brightness(
      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")],
      factor: Annotated[float, Field(description="亮度调整因子，1.0为原始亮度，>1.0变亮，<1.0变暗", gt=0)]
  ) -> str:
      """调整图片亮度"""
      try:
          result = safe_run_async(color_adjust_brightness(image_source, factor))
          return result[0].text
      except Exception as e:
          return json.dumps({
              "success": False,
              "error": f"调整亮度失败: {str(e)}"
          }, ensure_ascii=False, indent=2)

• tools/color_adjust.py:25-44 (schema)

  Explicit JSON schema definition for the adjust_brightness tool input validation, part of get_color_adjust_tools() function.

  Tool(
      name="adjust_brightness",
      description="调整图片亮度",
      inputSchema={
          "type": "object",
          "properties": {
              "image_source": {
                  "type": "string",
                  "description": "图片数据（base64编码）或文件路径"
              },
              "factor": {
                  "type": "number",
                  "description": "亮度调整因子（0.0-2.0，1.0为原始亮度）",
                  "minimum": 0.0,
                  "maximum": 2.0
              }
          },
          "required": ["image_source", "factor"]
      }
  ),