Single tool 'calculate' has a complete input schema with proper types and descriptions for all three parameters (operation, x, y). Tool description is present but minimal (23 chars). Schema is well-formed with required fields and type constraints. However, the description lacks context about when to use this tool, what it returns, or error handling guidance. No output schema is documented. Error handling for division by zero exists in code but is not reflected in the tool definition or description. Parameter 'operation' lacks an enum constraint despite accepting only four specific values (add, subtract, multiply, divide), forcing LLMs to guess valid options.

• Add enum constraint to 'operation' parameter: {"enum": ["add", "subtract", "multiply", "divide"]}
• Expand tool description to 80-150 chars: 'Performs basic arithmetic operations (add, subtract, multiply, divide) on two numbers. Returns the result as a string. Division by zero returns an error.'
• Document output schema: 'Returns a CallToolResult with a single TextContent item containing the numeric result as a formatted string.'
• Enhance 'operation' parameter description: 'The arithmetic operation to perform. Must be one of: add, subtract, multiply, divide. Division by zero will return an error.'
• Add numeric constraints to x and y parameters: 'A number (float64). For divide operations, y cannot be zero.'

Inferred effective spec: 2025-06-18+.

• Relies on Sampling (deprecated) - integrate directly with the LLM provider API