The server provides one calculator tool with a complete JSON Schema input definition and reasonable description. The tool is well-named (calculator), has a clear description (194 chars, within baseline 34-392), and all three parameters (a, b, operation) are typed and described. However, the server lacks output schema documentation, error handling guidance, and several descriptor patterns that would elevate it to production grade. The single-tool scope limits composition assessment, but the naming and schema are solid for what exists.

• Add explicit output schema documentation: 'Returns a JSON object with fields: result (number), operation (string), a (number), b (number).'
• Document error cases in description: 'Returns an error message (string) if division by zero is attempted; message format is "Cannot divide {a} by zero."'
• Add readOnlyHint tool annotation in the MCP schema to indicate calculator is read-only and has no side effects.
• Specify numeric constraints in parameter descriptions: 'First operand (number, must be between -1e10 and 1e10)' and 'Second operand (number, must be between -1e10 and 1e10; division requires b ≠ 0).'
• Clarify division behavior: 'Division returns a floating-point result; for integer division, pass integer operands.' or define precision guarantees.
• Add an example to the tool description to show typical invocation: 'Example: a=10, b=5, operation="+" returns {result: 15, operation: "+", a: 10, b: 5}'.
• Consider adding a 'precision' or 'decimal_places' optional parameter if rounding is relevant, to give LLMs explicit control over output format.

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry