Server has 1 tool (calculate) with a clear description and well-formed schema. Naming is verb-based and unambiguous. Input parameters have type definitions and descriptions. However, output schema is not documented, error handling is not specified, and the tool lacks guidance on what happens after invocation (side effects, return structure). The server demonstrates basic competence but lacks production-grade polish in response documentation and error recovery patterns.

• Add a documented output schema in src/tools/calculate.ts or a README. Specify the exact structure returned by the tool, e.g., {result: number, operation: string}. This allows LLMs to plan chained calls and validate responses.
• Expand the tool description from 85 to 150-200 characters. Include the list of supported operations, constraints, and a hint about error recovery: 'Performs arithmetic operations (add, subtract, multiply, divide) on two numbers. Returns the numeric result. Division by zero returns an error; suggest alternative calculations.'
• Add explicit error handling in the tool implementation and document it in the description. For example: 'If division by zero is attempted, return an error with the message: "Cannot divide by zero. Please provide a non-zero divisor."'
• Consider adding parameter constraints to the description: 'a and b must be valid numbers. operation must be one of: add, subtract, multiply, divide.'
• Add idempotency annotation to the tool definition: this tool is read-only and safe to call multiple times with the same arguments. Use toolAnnotations feature (if available in elysia-mcp) to mark it as readOnlyHint=true.