Weather MCP has a single tool with clear naming, comprehensive descriptions, and well-defined input schema using Zod. The tool name 'getWeather' follows verb_noun convention (get prefix). Descriptions are detailed and context-aware, explaining defaults and providing guidance. Schema includes proper type coercion and enums. Error handling returns structured text responses. Main weaknesses: no output schema documentation, limited error classification, and no tool annotations for readOnlyHint despite being a read-only operation.

• Add a formal output schema comment documenting the response structure: { content: [{ type: 'text', text: string }], isError?: boolean }. Include field descriptions so callers know what to expect.
• Add tool annotations via server.tool() to declare readOnlyHint: true and idempotentHint: true. This helps LLMs understand the tool is safe to call repeatedly.
• Implement error categorization. Instead of a generic error return, classify errors as: RETRYABLE (API timeout, rate limit), USER_FIXABLE (missing coordinates, invalid unit), or FATAL (missing API key). Include recovery guidance: 'API key missing, configure ACCUWEATHER_API_KEY in environment.'
• Enhance parameter descriptions with examples of valid input ranges and formats. E.g., latitude: 'Decimal degrees, e.g. 40.7128 for New York (range: -90 to +90).'
• Document the AccuWeather API dependency and potential failure modes (rate limits, geolocation unavailable) in the tool description or server instructions.