Four tools with complete input schemas and descriptions, but descriptions are generic and lack LLM-optimized guidance. All tools are READ_ONLY (good for safety), but descriptions do not explain WHEN to use each tool vs. alternatives, dependencies between tools, or expected output structure. Parameter descriptions are minimal (e.g., 'Origin country code' lacks format/constraint details). No output schemas documented. Error handling absent, no guidance on invalid inputs or recovery paths. Naming is clear and verb-based, but composition could be tighter (estimate_shipping_rates and calculate_delivery_time overlap in purpose).

• Document output schemas for all tools. E.g., identify_carrier should return {carrier: string, trackingUrl: string, countries: string[]}. estimate_shipping_rates should return {estimates: [{carrier, service, costMin, costMax, daysMin, daysMax, currency}]}.
• Enhance parameter descriptions with format constraints. Change 'Origin country code (e.g., 'DE', 'FR')' to 'ISO 3166-1 alpha-2 country code (2 uppercase letters, e.g., DE, FR, US). Must match a supported country.'
• Add tool-selection guidance to descriptions. E.g., estimate_shipping_rates: 'Use this to get cost and delivery time estimates for a shipment. Call identify_carrier first if you only have a tracking number.'
• Implement input validation with actionable error messages. E.g., 'Invalid country code: got "de", must be uppercase ISO 3166-1 alpha-2 (e.g., DE, FR, US). Supported countries: [list]'.
• Clarify the relationship between estimate_shipping_rates and calculate_delivery_time. If they serve different purposes, rename one (e.g., get_shipping_cost vs get_delivery_estimate). If overlapping, merge or document the distinction.