The Etsy MCP server provides 7 tools with consistent naming, clear descriptions, and well-defined input schemas. All tools follow verb_noun naming conventions (search_, get_) and have substantive descriptions (90-190 chars). Input schemas are complete with proper JSON Schema types, enums, and min/max constraints. However, the server lacks output schema documentation, error handling guidance, and some parameter descriptions could be more specific about expected formats. No security patterns are evident (API key exposure, no permission gates). The server is STDIO-only, which caps protocol readiness at 50.

• Document output schemas for all 7 tools. Include example responses showing field names, types, and which fields are safe to pass to downstream tools. Prioritize chaining fields (shop_id, listing_id, user_id) that enable multi-step agent workflows.
• Implement structured error handling: catch axios errors, classify as 'not_found', 'rate_limited', 'invalid_input', 'auth_failed', or 'server_error', and return actionable guidance. E.g., 'Rate limited (429). Wait 60 seconds before retrying. Consider narrowing search scope to reduce API volume.'
• Add tool annotation objects to each tool definition: { readOnlyHint: true } for all tools. This signals to MCP clients that these tools are read-only and safe to invoke without confirmation.
• Enhance parameter descriptions with format constraints: E.g., 'shop_name (string, 1-255 chars, URL-safe): The shop name or slug from Etsy shop URLs.' Include min/max string length in schema if not already present.
• Add result truncation and pagination clarification: Modify limit descriptions to state 'Results are paginated. Pass offset to fetch additional pages. Returns up to N items per page.' Ensure responses include 'total_count' or 'has_more' to signal pagination availability.
• Migrate from environment variable secret injection to a vault-based pattern or implement a secure credential store. If ETSY_API_KEY must remain in environment, document that the MCP server should be run in a trusted, isolated environment with restricted logs.
• Add dependency hints in tool descriptions. E.g., 'search_shops returns shop_id; use it with get_shop_listings to retrieve all products from a specific shop.' This guides agents toward efficient multi-step workflows.