Crystal Suppliers MCP demonstrates solid definition quality with complete input/output schemas, comprehensive parameter descriptions, and thoughtful domain-specific constraints. All 6 tools have explicit Zod schemas with typed fields and descriptions. Tool names follow verb_noun convention (search_, get_, list_, build_, prepare_). Descriptions are domain-aware and include coverage disclaimers (e.g., 'advisory only' for non-bracelet categories). However, descriptions average ~180 chars (within baseline 194), some parameter descriptions are terse, and error handling lacks recovery guidance. Output schemas are well-structured with coverage/sourceUrls/warnings fields, but error responses are not visible in the code sample.

• Add explicit error responses with recovery guidance. E.g., for invalid SKU: 'Invalid SKU format (expected 1-160 alphanumeric). Try crystal_search_products() to discover valid SKUs.'
• Expand parameter descriptions for 'channel', 'destination', 'packaging', 'contentAssets' to include valid values, examples, or when they affect filtering. E.g., 'channel: Sales channel (e.g., wholesale, retail, direct-to-consumer). Affects sourcing guidance and supplier recommendations.'
• Document the 'relatedProducts' field in crystal_get_product output. E.g., 'relatedProducts: Array of similar bracelets by material or benefit tag. Use to explore alternatives or build a shortlist.'
• Add a 'draftOnly' confirmation step or return a 'reviewUrl' in crystal_prepare_inquiry output so agents can surface the draft to users before any submission occurs.
• Clarify the distinction between 'verified_catalog' (bracelets only) and 'advisory_only' (beads, accessories, raw_materials) in tool descriptions. E.g., 'Verified products are limited to the 104-SKU bracelet catalog; other categories return advisory guidance only and do not guarantee SKU availability.'

Inferred effective spec: 2025-06-18+.

• Relies on Stateful initialize / Mcp-Session-Id (removed; protocol is stateless) - make each request self-contained