The server defines two tools with partial quality. Both tools have schemas with Zod validation and basic descriptions, but the descriptions are minimal (10-16 chars each). The 'add' tool is trivially simple with only 2 parameters. The 'calculate' tool is slightly more complex with an enum constraint on 'operation', but lacks error handling documentation. Parameter descriptions are present but terse. No output schemas are documented. Division by zero is handled inline but the error response is unstructured text, not actionable guidance. The server uses HTTP transport via Cloudflare Workers, which is current-spec compliant.

• Expand tool descriptions to 50-200 characters each. Example: 'add' → 'Adds two numbers and returns the sum. Use for simple arithmetic when you need to combine numeric values.'
• Document output schemas explicitly. Declare that both tools return {type: 'text', text: string} or a more structured {result: number, operation: string} format.
• Enhance parameter descriptions with constraints and examples. Example: 'a' → 'First operand: a positive or negative number (no limits)'.
• Replace the division-by-zero error string with a structured error object. Example: {type: 'error', code: 'DIVISION_BY_ZERO', message: 'Cannot divide by zero.', recovery: 'Ensure the divisor is non-zero and retry.'}
• Consider splitting 'calculate' into separate verb_noun tools: 'add_numbers', 'subtract_numbers', 'multiply_numbers', 'divide_numbers'. This aligns with pattern:tool single-responsibility principle.
• Add tool annotations to the 'server.tool()' registration. Per MCP spec, declare {readOnlyHint: true} for all three tools to signal they are safe to call without side effects.