The server has six well-named, read-only tools with complete input schemas and descriptions. Naming follows verb_noun conventions (search_cards, browse_sets, card_versions, etc.). All tools have descriptions between 60 - 120 chars, which is concise but adequate. All tools have documented input parameters with types and descriptions. However, output schemas are not visible in the provided code, the tools are registered but their return types are not documented. Error handling is present (errorReporting=true) but the actual error recovery guidance in tool implementations is not shown. The server uses a static JSON data source (one-piece-card-game-json), which keeps logic simple but limits dynamic data freshness. Overall, definition quality is solid for a read-only domain but falls short of A-grade due to missing output schema documentation.

• Document output schemas for all tools. For search_cards, explicitly declare: { cards: Card[], total: number }. For browse_sets: { sets: Set[] } or { sets: Set[], currentSet: Set, cards: Card[] }. This enables LLMs to plan downstream field extraction.
• Add 'total' or 'has_more' to paginated tool responses. Update search_cards and find_counters descriptions to state: 'Returns up to {limit} results (default 10). Response includes a total count for pagination.' Document the response structure.
• Make 'query' required or add a validation step. If search_cards with zero filters returns thousands of cards, either make query or another filter required, or cap the default limit to 5 and note: 'Query is optional but recommended, omitting it returns the first {limit} cards.'
• Improve analyze_cost_curve validation. Show example error handling: 'If deck list format is invalid, return a clear error: "Invalid deck list line 2: '4 Luffy' expected '4 CardName' or '4x CardNumber'. Provide a corrected example.'
• Add tool annotations to all tool definitions. In tool registration code (likely in each tools/*.ts file), add readOnlyHint: true and idempotentHint: true to the tool schema. This documents safety semantics to the protocol.
• For browse_sets, clarify whether set_name is case-sensitive. Current code uses .toLowerCase() on the data source, so 'OP-01' and 'op-01' should both work, but this is not documented. Add: 'Set names are case-insensitive (e.g., OP-01, op-01, ROMANCE DAWN all match).'
• For find_counters and browse_leaders, consider adding sort order and grouping options (e.g., sort: 'cost_asc', 'power_desc'). Current responses have unstated ordering, which may confuse users expecting a canonical ranking.