This MCP server presents a single tool (calculator) with moderate structural issues. The tool definition is loaded from an external JSON file (/tools/calculator.json) which is NOT visible in the provided source code. While the CalculatorTool.java class shows execution logic with proper error handling (division by zero, invalid operations), the actual schema definition cannot be verified. The input schema appears to be present based on the preamble (a: number, b: number, operation: enum), but without seeing the JSON file, proper schema validation cannot be performed. The tool description in Korean ('수학 계산을 수행합니다' = 'Performs mathematical calculations') is extremely brief (11 chars in English equivalent) and lacks actionable detail for LLM selection. No parameter-level descriptions are visible in the code, the description quality must be inferred from the JSON file. The naming is generic ('calculator' vs 'calculate_math', 'add_numbers', etc.) and does not follow the verb_noun convention. Error handling within CalculatorTool.execute() is reasonable (throw exceptions with messages), but there is no evidence of structured error responses or recovery guidance.

• Provide the /tools/calculator.json schema file for review. Ensure it includes detailed parameter descriptions (e.g., 'a' and 'b' should explain data type, range, and constraints; 'operation' should list valid enums).
• Expand tool description from 11 chars to 100 - 200 chars. Example: 'Performs basic arithmetic (add, subtract, multiply, divide) on two numbers. Returns the result as a decimal. Use for mathematical calculations in chat context.'
• Rename tool from 'calculator' to 'calculate_math' or 'calculate_numbers' to follow verb_noun convention.
• Document the output schema explicitly. What does McpMessage contain? Example: 'Returns {"result": <number>, "expression": <string>}' so LLM knows the response structure.
• Enhance error messages in CalculatorTool.execute() to be LLM-actionable. Instead of throwing bare exceptions, return structured McpMessage errors: 'Invalid operation: got "divide", must be one of: add, subtract, multiply, divide. Retry with a valid operation.'
• Add parameter constraints in schema: 'a' and 'b' should specify type (number), and suggest ranges if applicable (e.g., -1e10 to 1e10 to prevent overflow). 'operation' enum is correct; ensure description text matches the enum values exactly.