Critical failures across all dimensions. All 4 tools lack parameter descriptions entirely (null values in schema). Tool descriptions are missing or trivial. No output schemas documented. The 'add' and 'echo' tools have generic names that don't follow verb_noun conventions. 'fetch-carts' exposes external API details without explaining purpose or return structure. No error handling guidance. Parameter types are present (Zod schemas) but descriptions are completely absent, violating the 100% baseline for A+ tools.

• Add non-empty descriptions to all 4 tools (50-200 chars each). Example: 'add' → 'Adds two numbers and returns the sum. Use for arithmetic calculations.'
• Add descriptions to every parameter. Example: 'a' → 'First number to add (integer or decimal)'; 'b' → 'Second number to add (integer or decimal)'.
• Document output schemas for each tool. Example: 'add' returns {type: 'number', description: 'Sum of a and b'}.
• Rename tools to follow verb_noun convention: 'add' → 'compute_sum', 'echo' → 'echo_message', 'calculate-bmi' → 'compute_bmi', 'fetch-carts' → 'get_cart_by_id'.
• Add error handling with recovery guidance. Example: 'fetch-carts' should catch network errors and return 'Failed to fetch cart. Verify cart ID exists and network is reachable.'