This server has significant definition quality gaps. While tool schemas are present and mostly well-formed, descriptions contain non-English text (Japanese) that LLMs may struggle to interpret, parameters lack detailed constraints, and there is no error handling or recovery guidance. The server bridges to ComfyUI but does not follow LLM-centric tool design patterns. Tool naming is reasonable (verb_object style) but descriptions are in Japanese, limiting cross-language agent compatibility. No tool annotations (readOnlyHint/destructiveHint) are present despite clear semantic differences between tools.

• Translate all tool descriptions and parameter descriptions to English (or at minimum provide English translations alongside Japanese). Japanese descriptions prevent cross-language agent compatibility and limit LLM reasoning.
• Add tool annotations via fastmcp: @mcp.tool(hints=['readOnly']) for get_picture, get_caption, get_tag; use @mcp.tool(hints=['destructive']) for generate_picture. This signals intent to the agent.
• Expand generate_picture description to include: what happens on failure, expected return format (URL string), and any retry guidance. E.g., 'Returns a ComfyUI view URL pointing to the generated image. If ComfyUI is offline (connection refused), this tool will fail; verify the COMFYUI_URL environment variable points to an accessible server.'
• Document parameter constraints in descriptions: 'prompt (string, max 500 chars, English only; non-ASCII characters will be rejected)'. Add validation inside the tool that returns clear error messages like 'Invalid prompt: contains non-ASCII characters. Please provide English text only.'
• Document the output schema for each tool in docstrings: 'Returns: str - a full HTTP URL to the generated image on the ComfyUI server (e.g., http://localhost:8188/view?subfolder=outputs&filename=image_123.png)'.
• Modify get_picture to return a structured response: {image: Image(data=..., format='png'), subfolder: str, filename: str, url: str}. This enables chaining, if the agent later calls get_caption with the same image, it has the subfolder/filename.