Three tools with basic schemas and descriptions, but significant gaps in parameter documentation, error handling, and output schema clarity. check_auth_status and authenticate lack input parameter descriptions (empty objects). upload_from_url has reasonable parameter coverage but missing output schema documentation. No error recovery guidance, no idempotency hints, and descriptions are generic (10-50 chars). Tool composition is reasonable but lacks chaining metadata. No tool annotations (readOnlyHint, destructiveHint). Baseline: 549 production tools average 194 chars in description and 100% have param descriptions, this server has ~40 chars avg and 0% param descriptions for empty inputs.

• Add output schema documentation to all tools. For check_auth_status, document: {authenticated: boolean, message: string}. For authenticate, document: {success: boolean, message: string, [error_code: string]}. For upload_from_url, document: {success: boolean, message: string, video_id?: string, video_url?: string}.
• Add tool annotations via FastMCP: @mcp.tool(annotations={'readOnlyHint': True}) for check_auth_status; @mcp.tool(annotations={'destructiveHint': True}) for authenticate and upload_from_url.
• Enhance error messages with recovery guidance. E.g., authenticate() should return: 'Missing YouTube API credentials. Set YOUTUBE_CLIENT_ID and YOUTUBE_CLIENT_SECRET in Claude Desktop config, then retry.' instead of bare message.
• Document upload_from_url 'url' parameter: 'URL of the video to download (http/https only, max 2GB file size, supports MP4/WebM/MOV)' and add validation to reject invalid schemes.
• Add parameter descriptions to empty input schemas. For check_auth_status, add description: 'Checks if the user has a valid, non-expired YouTube OAuth token stored locally. No parameters required. Returns authentication status and any refresh errors.' This guides LLM on when to call it.