Single tool 'add' has a valid schema with typed parameters (a, b as numbers) but critical gaps prevent higher scoring. Tool description is minimal (10 chars) and lacks context on when/why to use it. No output schema documented. No error handling guidance. No composition hints. The tool is READ_ONLY but this is not reflected in the description. Baseline: 100% of A+ tools have param descriptions; this has zero.

• Add descriptions to parameters a and b: e.g. 'a: "First number (any real value)"' and 'b: "Second number (any real value)"'.
• Expand tool description to 50-150 chars: 'Adds two numbers and returns their sum. Use this for arithmetic operations. Returns a single numeric result.'
• Document output schema in description or via structured response: 'Returns {content: [{type: "text", text: string}]} where text is the numeric sum.'
• Rename tool from 'add' to 'add_numbers' to follow verb_noun convention and improve LLM intent inference.
• Add input validation and error guidance: catch non-numeric inputs and return 'Invalid input: a and b must be numbers. Got a={a}, b={b}.'