Image Processing MCP Server

Instructions

Implementation Reference

• tools/color_adjust.py:290-343 (handler)

  Core handler function that loads the image, applies contrast enhancement using PIL ImageEnhance.Contrast, generates output image data, and returns JSON result.

  async def adjust_contrast(image_source: str, factor: float) -> list[TextContent]:
      """
      调整图片对比度
      
      Args:
          image_source: 图片数据（base64编码）或文件路径
          factor: 对比度调整因子（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"对比度因子必须在0.0-2.0范围内: {factor}")
          
          # 加载图片
          image = processor.load_image(image_source)
          
          # 调整对比度
          enhancer = ImageEnhance.Contrast(image)
          enhanced_image = enhancer.enhance(factor)
          
          # 输出处理后的图片
          output_info = processor.output_image(enhanced_image, "contrast")
          
          result = {
              "success": True,
              "message": f"对比度调整成功: 因子 {factor}",
              "data": {
                  **output_info,
                  "contrast_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))]
          
      except Exception as e:
          error_result = {
              "success": False,
              "error": f"对比度调整失败: {str(e)}"
          }
          return [TextContent(type="text", text=json.dumps(error_result, ensure_ascii=False))]

• main.py:399-412 (registration)

  MCP tool registration decorator @mcp.tool() that wraps the handler, provides input schema via Annotated Fields, and handles execution with safe_run_async.

  @mcp.tool()
  def adjust_contrast(
      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="对比度调整因子，1.0为原始对比度，>1.0增强，<1.0减弱", gt=0)]
  ) -> str:
      """调整图片对比度"""
      try:
          result = safe_run_async(color_adjust_contrast(image_source, factor))
          return result[0].text
      except Exception as e:
          return json.dumps({
              "success": False,
              "error": f"调整对比度失败: {str(e)}"
          }, ensure_ascii=False, indent=2)

• tools/color_adjust.py:45-64 (schema)

  Explicit JSON schema definition for the adjust_contrast tool input, including properties, descriptions, and validation constraints (min/max for factor). Used in get_color_adjust_tools().

  Tool(
      name="adjust_contrast",
      description="调整图片对比度",
      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": "对比度调整因子（0.0-2.0，1.0为原始对比度）",
                  "minimum": 0.0,
                  "maximum": 2.0
              }
          },
          "required": ["image_source", "factor"]
      }
  ),