Single tool with a basic but incomplete definition. The tool is explicitly registered with name, description, and schema, but lacks critical details: parameter descriptions are minimal, output schema is undocumented, error handling is absent, and the implementation exposes no guidance for LLM recovery. The description is generic (22 chars, at minimum threshold). The input schema is present but the 'city' parameter description is bare ('City name', 9 chars, below recommended 50-200 char range for LLM clarity). No output schema is documented; LLMs cannot predict return structure. Error handling returns unstructured text rather than structured errors with recovery guidance. No mention of what happens on API failures (timeouts, invalid responses, quota limits). The tool violates several critical patterns: response-shaper (no documented output), recovery-guide (no error guidance), tool-description (param description too brief).

• Expand the tool description to 50 - 200 chars: 'Fetches current weather and hourly forecast for a city. Returns temperature, precipitation, and daylight status. Use this when the user asks about weather conditions or forecasts for a specific location.'
• Document the 'city' parameter description: 'City name (1 - 100 chars, alphanumeric and spaces). Must be a real geographic location recognized by Open-Meteo geocoding service. E.g. "New York", "San Francisco", "London".'
• Define the output schema explicitly in code or a comment: {temperature_2m: number, precipitation: number, is_day: boolean, current: {...}, hourly: {...}}. Consider wrapping the raw API response and stripping unnecessary fields (audit metadata, internal timestamps) to keep token count low.
• Add structured error handling: (1) If geocoding returns 0 results, return {type: 'text', text: 'City not found. Try a major city name like New York, London, or Tokyo.'} with recovery hint. (2) If the weather API fails, catch the error and return {type: 'text', text: 'Weather service unavailable. Please try again in a few moments.'}, include retry guidance.
• Add input validation: check that 'city' is non-empty and under 100 characters. Return a clear validation error if constraints are violated.
• Add timeout to fetch() calls (e.g., AbortController with 5s timeout) and catch timeout errors with a user-friendly message and retry guidance.
• Consider adding a response count limit and pagination (though a single weather request is typically small, document that responses are capped at ~2KB).