Single well-defined calculator tool with complete schema, clear description, and proper parameter annotations. Naming follows verb-noun convention ('calculator' is noun-like but acceptable for domain context). Description is concise (34 chars) but adequate. Input schema uses Zod with full type definitions and per-parameter descriptions. Error handling for division by zero demonstrates defensive programming. However, tool is trivial (arithmetic only), lacks real-world complexity, and the description could be more prescriptive about when/why to use it. Output format is text-only rather than structured. No multi-step composition patterns demonstrated. Server is a starter template, not a production-grade tool ecosystem.

• Expand calculator description to ~100-150 chars: 'Perform basic arithmetic operations (add, subtract, multiply, divide). Returns numeric result. Use when LLM needs to compute exact values for math-heavy tasks.'
• Change output to structured JSON: {content: [{type: 'text', text: '${a} ${operation} ${b} = ${result}'}, {type: 'object', object: {result, operation, a, b}}]} so downstream tools can parse result programmatically.
• Add a second example tool (e.g., unit converter or stats calculator) to demonstrate tool composition, chaining, and idempotent patterns.
• Document error handling in description: 'Throws error if denominator is zero in division. Returns precise decimal results.'
• Consider adding a 'precision' optional parameter to control decimal places in output, demonstrating optional params with defaults.

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

• Relies on Stateful initialize / Mcp-Session-Id (removed; protocol is stateless) - make each request self-contained