Vision MCP server has 4 tools with basic schemas and descriptions, but significant gaps in parameter documentation, error handling, and output schema clarity. Tool names are action-oriented (screenshot, list_windows, analyze_image, ocr_image), which is good. However, descriptions lack depth on when to use each tool vs. alternatives, parameter descriptions are sparse or missing, and output schemas are not documented. No error recovery guidance. The server exposes API keys via environment variables (correct), but tool implementations lack input validation and actionable error messages.

• Document output schemas for all tools. E.g., screenshot returns {file_path: string, width: int, height: int, format: string}. analyze_image returns {analysis: string, confidence?: number}. This enables LLMs to chain tools and extract required fields.
• Add parameter descriptions for list_windows (currently empty input schema). Explain that it returns an array of {index: number, title: string} and when to call it (e.g., 'Call before screenshot with mode=window to discover available windows').
• Document parameter dependencies in screenshot: 'window_title is required if and only if mode=window. Omit for mode=primary or mode=full.'
• Add input validation and actionable error messages. E.g., if image_source is unreachable: 'Image URL returned 404. Verify the URL is correct and publicly accessible.' If Ollama is offline: 'Local Ollama model unavailable. Falling back to cloud API (Qwen VL Plus). Ensure DASHSCOPE_API_KEY is set.'
• Expand tool descriptions to clarify when to use each. E.g., analyze_image: 'Use for detailed visual analysis (objects, text, layout). For text extraction only, use ocr_image (faster, cheaper).'