Solid foundation with consistent naming (verb_noun pattern), clear descriptions (avg 120 chars), and complete Zod schemas with type constraints. All 11 tools are read-only and money-safe by design. However, output schemas are not documented, LLMs cannot predict response structure. Parameter descriptions lack format/constraint details (e.g., ISO-8601 format stated but no regex/pattern). Error handling returns JSON but lacks recovery guidance or error classification. No tool annotations (readOnlyHint, idempotentHint). Missing batch operations and composition hints.

• Document output schemas for all tools. Example: 'Returns {environment: string, status: string, timestamp: ISO-8601}' so LLMs know what fields to expect and can chain tools correctly.
• Enhance error responses with recovery guidance. Instead of {error: 'Not found'}, return {error: 'Invoice INV2-XXXX not found', recovery: 'Try paypal_list_invoices() to find valid invoice IDs', retryable: false}.
• Replace example-based parameter descriptions with enum constraints. Change 'e.g. S (success), P (pending), V (reversed)' to enum: ['S', 'P', 'V'] with descriptions for each value.
• Add tool annotations via MCP SDK. Mark all tools with readOnlyHint: true and idempotentHint: true so LLMs know they are safe to retry without side effects.
• Document pagination limits in list tool descriptions. Example: 'Returns up to 100 transactions per page. Include total_count in response so LLMs know if more results exist.'