Single tool 'calculate' has a complete input schema with proper types and enum constraints for the 'op' parameter. Description is present (94 chars) and explains the core function. However, the description lacks critical context: it does not state WHEN to use this tool vs alternatives, does not mention that division by zero returns null, and omits any guidance on error handling or recovery. Parameter descriptions are entirely absent, 'a', 'b', and 'op' have no individual documentation explaining their roles or constraints. Output schema is not documented in the tool definition. The tool is READ_ONLY but lacks explicit idempotentHint annotation. No error handling guidance is provided for edge cases (e.g., division by zero). Overall, the tool meets minimum viability but falls short of production-grade clarity expected for agent-facing tools.

• Add individual descriptions to each parameter: 'a' (first operand, numeric), 'b' (second operand, numeric), 'op' (operation: add, subtract, multiply, or divide).
• Expand tool description to 150 - 250 chars: explain that this performs basic arithmetic, mention division by zero returns null, and state when to use it (e.g., 'Use for simple numeric calculations; for complex math, consider a specialized tool').
• Document the output schema in the tool definition: specify that the response contains a 'text' field with the numeric result as a string.
• Add error handling guidance: 'If division by zero occurs, the result is null. Suggest to the user that division by zero is undefined, or offer an alternative calculation.'
• Add idempotentHint: true annotation to signal that the tool is safe to retry without side effects.