Single tool 'add' has a clear verb-noun name and basic schema with typed parameters. However, the description is minimal (22 chars) and lacks context about when/why to use it. Parameters 'a' and 'b' have descriptions but are generic. No output schema is documented. No error handling guidance. The tool is trivial (arithmetic) and does not reflect production patterns. Baseline: 194 chars for tool descriptions, 72 chars for param annotations, this server falls well short.

• Expand tool description to 50 - 150 chars explaining purpose, use case, and output. Example: 'Adds two numbers and returns the sum. Use for arithmetic calculations. Returns a single numeric result.'
• Document the output schema explicitly. In code: add description like 'Returns {result: number}, the sum of a and b.'
• Add numeric constraints to parameter descriptions. Example: 'a: A numeric value (integer or float). No bounds enforced; very large values may cause overflow.'
• Implement input validation and return actionable error messages. Example: 'Invalid input: a must be a number, got string. Please provide numeric values.'
• Replace toy 'add' tool with real domain operations (e.g., if this is a Cloudflare Workers MCP, expose KV operations, D1 queries, or Workers AI calls).