Two tools with explicit schemas using Zod, minimal but adequate descriptions. Naming follows verb_noun convention. Schemas are visible and typed. However, descriptions are very short (10-56 chars), parameter descriptions are minimal, no output schema documentation, no error recovery guidance. Tool 'add' is trivially simple but redundant with 'calculate'. Error handling for division by zero is inline but lacks LLM-actionable messaging. Average tool score: 68.

• Expand 'add' description to ~100 chars: 'Adds two numbers and returns the sum. Use for simple arithmetic operations. Parameters: two numbers (a, b). Returns the numeric result.'
• Expand 'calculate' description to ~150 chars: 'Performs arithmetic operations (add, subtract, multiply, divide) on two operands. Specify the operation and two numbers. Division by zero returns an error. Returns the numeric result.'
• Document output schema for each tool: 'Returns {"result": <number>}' or similar in the docstring. Make it explicit what fields the LLM should expect.
• Add parameter descriptions with constraints: 'a (number): First operand. Any real number.' and 'b (number): Second operand. For divide, must be non-zero.'
• Refactor error handling to return structured errors: instead of plain text, return {"error": "division_by_zero", "message": "Cannot divide by zero. Verify operand b is non-zero and retry."} so LLMs can parse and act on the error.
• Consider consolidating 'add' into 'calculate' to reduce tool set complexity. Keep 'add' only if there's a strong use case for a lightweight addition-only endpoint.
• Add a 'Permissions/Scope' note if any scopes apply (e.g., 'read:math'). Even for simple calculators, document that no special permissions are needed.