Single tool 'fetch-weather' has a clear verb-starting name and basic schema, but critical gaps undermine production readiness. Description is minimal (34 chars, below the 50-200 char ideal for LLM selection). Input schema is present and typed (city: string) with description, meeting basic requirements. However, no output schema is documented, the tool returns unstructured JSON from an external API without describing what fields the LLM should expect. Error handling returns plain text fallbacks without guidance on recovery or classification (retryable vs fatal). No validation of the city parameter, no handling of edge cases (empty string, invalid characters), and no result limits or pagination support. The tool lacks idempotency hints, permission gates, and security considerations. Overall structure is functional for a basic example but far below production grade.

• Expand tool description to 80-150 characters explaining: What the tool does (fetch current and forecast weather), when to use it (when a user asks about weather for a location), what it returns (current temperature, hourly forecast, precipitation), and any prerequisites (city name must be a real place).
• Document the output schema explicitly. E.g., 'Returns: {current_temperature_c: number, precipitation_mm: number, hourly_temps: [number], forecast_day: string}', matching what the tool actually extracts and returns.
• Add input validation: require city be 2-50 characters, reject empty strings, validate against common punctuation patterns. Return clear error: 'City name must be 2-50 chars; got "<value>"'.
• Categorize errors: distinguish 'No city found (try search_cities first)' from 'API timeout (safe to retry)' from 'Invalid city format (check spelling)'.
• Set explicit timeout (e.g., 5 seconds) on fetch calls. Return: 'Weather API timeout after 5s. This is safe to retry.'
• Filter and document API response fields. E.g., extract only current.temperature_2m, hourly.temperature_2m (limit to next 24 hours), omit metadata. Return structured: {current_temp: number, forecast_hourly: [number], units: 'celsius'}.
• Add dry-run support or confirm-before-execute pattern if the tool will later support subscriptions or alerts.
• Consider splitting into get_current_weather (just now) and get_weather_forecast (next N days) for clearer composition.