26 tools with consistent verb_noun naming (grocy_*). All have descriptions (avg ~80 chars, within baseline). Input schemas present with types and descriptions for most parameters. However, output schemas are undocumented, tools return JSON strings without declared structure. Error handling is generic ('Error getting X: {exc}') with no recovery guidance. Parameters like 'payload_json' accept raw JSON strings instead of structured objects, forcing LLMs to construct JSON manually. Missing tool annotations (readOnlyHint, destructiveHint). Pagination implemented but inconsistently (some tools cap at 100, others 500). No per-tool risk classification visible in schema.

• Replace 'payload_json' string parameters with structured Pydantic models. Define separate input classes for each write operation (e.g., AddStockInput with amount, best_before_date, price fields) and expose them as tool parameters. This lets LLMs compose requests naturally without manual JSON construction.
• Document output schemas for all tools. For list_products, declare: 'Returns array of {id: int, name: str, description: str, active: bool, ...}'. For get_product, declare the full product object structure. Use JSON Schema in the tool definition or a separate schema document.
• Enhance error messages with recovery guidance. Instead of 'Error getting product 123: 404', return 'Product 123 not found. Try grocy_search_products(query="...") to find the correct product ID.' Classify errors as retryable (network timeout) vs user-fixable (invalid ID) vs fatal (auth failure).
• Add tool annotations to the MCP schema. Mark read-only tools with readOnlyHint=true, destructive tools with destructiveHint=true, and idempotent tools with idempotentHint=true. This enables clients to enforce safety policies and warn users before destructive operations.
• Implement a confirmation pattern for grocy_delete_entity_object. Return a result with 'input_required' status asking 'Delete {entity} {object_id}? This cannot be undone.' and require explicit user confirmation before executing the deletion.