AWS Nova Canvas MCP Server

Instructions

Generate an image from a text prompt. After generation, you can use the show_image tool to view the thumbnail.

Args:
    prompt: Text prompt for generating an image (maximum 1024 characters)
    negative_prompt: Text prompt for excluding attributes from generation (maximum 1024 characters)
    height: Image height (pixels)
    width: Image width (pixels)
    num_images: Number of images to generate (maximum 4)
    cfg_scale: Image matching degree for the prompt (1-20)
    seed: Seed value for image generation
    open_browser: Whether to open the image in the browser after generation
    
Returns:
    Dict: Dictionary containing the file path of the generated image and the thumbnail image

Implementation Reference

• aws_nova_canvas_mcp/tools/text_to_image.py:11-79 (handler)

  The main handler function for the text_to_image tool, which generates images from text prompts using AWS Bedrock and handles validation, generation, and saving.

  async def text_to_image(
          prompt: str,
          negative_prompt: str = "",
          height: int = 1024,
          width: int = 1024,
          num_images: int = 1,
          cfg_scale: float = 8.0,
          seed: int = 0,
          open_browser: bool = True,
          output_path: str = None,
  ) -> Dict[str, Any]:
      """
      Generate an image from a text prompt. If a color palette is specified, use the color_guided_generation tool first.
      
      Args:
          prompt: Text prompt for generating an image (maximum 1024 characters)
          negative_prompt: Text prompt for excluding attributes from generation (maximum 1024 characters)
          height: Image height (pixels)
          width: Image width (pixels)
          num_images: Number of images to generate (maximum 4)
          cfg_scale: Image matching degree for the prompt (1-20)
          seed: Seed value for image generation
          open_browser: Whether to open the image in the browser after generation
          output_path: Absolute path to save the image
          
      Returns:
          Dict: Dictionary containing the file path of the generated image and the thumbnail image
      """
      try:
          # Validate prompt length
          if len(prompt) > 1024:
              raise ImageError("Prompt cannot exceed 1024 characters.")
          if len(negative_prompt) > 1024:
              raise ImageError("Negative prompt cannot exceed 1024 characters.")
  
          if num_images < 1 or num_images > 4:
              raise ImageError("num_images must be between 1 and 4.")
  
          body = json.dumps({
              "taskType": "TEXT_IMAGE",
              "textToImageParams": {
                  "text": prompt,
                  "negativeText": negative_prompt
              },
              "imageGenerationConfig": {
                  "numberOfImages": num_images,
                  "height": height,
                  "width": width,
                  "cfgScale": cfg_scale,
                  "seed": seed
              }
          })
  
          # Generate image
          image_bytes = generate_image(body)
  
          # Save image
          image_info = save_image(image_bytes, open_browser=open_browser, output_path=output_path)
  
          # Generate result
          result = {
              "image_path": image_info["image_path"],
              "message": f"Image generated successfully. Saved location: {image_info['image_path']}"
          }
  
          return result
  
      except Exception as e:
          raise McpError(f"Error occurred while generating image: {str(e)}")

• aws_nova_canvas_mcp/server.py:28-31 (registration)

  Registration of the text_to_image tool with the FastMCP server instance.

  mcp.add_tool(text_to_image, 
               "text_to_image", 
               """Generate an image from a text prompt using aws nova canvas model. 
               If a color palette is specified, use the color_guided_generation tool first.""")