The Weather MCP Server has two clearly named tools with good descriptions and partial schema coverage. Both tools follow verb_noun naming (get_alerts, get_forecast), matching Arcade baseline conventions. Tool descriptions are substantive (150-250 chars), exceeding the minimum but some lack actionable guidance for LLM selection. Input schemas are present with type declarations and parameter descriptions, though output schemas are undocumented. Error handling is minimal, responses include generic error messages without recovery guidance or categorization. No output schema documentation forces LLMs to infer response structure, violating pattern:tool. Parameters accept user inputs without validation constraints (state codes, coordinates), missing enums, ranges, and format specifications.

• Document output schemas in code comments or docstrings. For get_alerts, specify: 'Returns {state: str, alerts: [{event: str, area: str, severity: str, description: str, instructions: str}], alert_count: int, message: str} or {error: str} on failure.'
• Add enum constraint for 'state' parameter: restrict to valid 50 US state/territory codes (AL, AK, AZ, ..., WY). Remove example values; replace with 'Two-letter US state code (uppercase only)'.
• Add numeric range constraints: latitude ∈ [-90, 90], longitude ∈ [-180, 180]. Document precision as 'decimal degrees to at least 2 decimal places (e.g., 37.77 for ~1 km precision)'.
• Enhance error messages with recovery paths: 'Invalid state code, valid codes: AL, AK, AZ, ... Try searching for your state or consult NWS documentation.' Return error categorization: {error: str, type: 'invalid_input'|'not_found'|'service_unavailable', suggestion: str}.
• Clarify tool selection in descriptions: get_alerts → 'Retrieve current weather warnings, watches, and advisories'; get_forecast → 'Retrieve multi-day temperature and condition forecasts.' Add 'Call get_alerts first to check for active weather threats in the region before requesting forecast.'
• Validate inputs inside tools: check state code against a whitelist; clamp/validate lat/lon before making NWS API calls. Return structured validation errors: {error: 'Invalid latitude: 95.5, must be between -90 and 90', field: 'latitude', value: 95.5, constraint: '[-90, 90]'}.