Server has 5 well-named tools with clear verb-noun patterns (get_*, add_*, edit_*, delete_). Descriptions are present and contextual (avg ~150 chars), explaining WHEN to use each tool. Input schemas are properly typed with JSON Schema. However, output schemas are completely undocumented, no return type specifications visible. Error handling is minimal; tools will fail silently on auth/API errors without recovery guidance. Parameter descriptions are adequate but lack format constraints (e.g., no enum for list_id validation, no min/max for batch sizes). The server instructions are excellent, but individual tool descriptions could be more concise and LLM-optimized.

• Document return types for all tools. E.g., get_lists should return {lists: [{id: string, name: string, item_count: number}], total: number}. get_items should return {items: [{id, name, quantity, unit, is_checked}], list_id, total}.
• Add error handling with recovery guidance. Wrap API calls in try-catch; on 401, return 'Authentication failed. Restart the server with --email and --password.' On 404, return 'List not found. Call get_lists() to see available lists.'
• Constrain array parameters: add max_items=50 to add_items, edit_items, delete_items. Document in descriptions: 'Maximum 50 items per call; batch large operations.'
• Add per-item success/failure reporting for batch operations. Instead of failing the entire add_items call if one item is invalid, return {succeeded: [...], failed: [{item, reason}]}.
• Add a dry-run or confirmation step for delete_items. Either add a 'confirm=true' parameter requiring explicit confirmation, or create a separate 'preview_delete_items' tool that shows what would be deleted.

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry