Single tool 'execute-graphql' with adequate naming and description but significant schema and composition issues. The tool accepts free-form GraphQL query strings, which bypasses structured input validation and forces LLMs to construct GraphQL syntax without schema-level guardrails. Parameter descriptions exist but lack constraint details. No output schema is documented. Tool conflates multiple distinct operations (addProduct, getProductById, getAllProducts) into one generic executor, violating single-responsibility principle. Error handling returns generic text responses rather than actionable guidance. The server demonstrates basic MCP structure but lacks production-grade tool design patterns.

• Split execute-graphql into three separate tools: create_product(name, price, category, description?, stock?), get_product_by_id(id), and list_products(). Each tool maps directly to a specific operation with structured input schemas. LLMs can then invoke the correct tool without needing to construct GraphQL syntax.
• Document a detailed output schema for each operation. Example for get_product_by_id: 'Returns {_id: string, name: string, description?: string, price: number, category: string, stock: integer}.' Include field types and optionality.
• Add enum constraints or detailed format descriptions to the query parameter if you must retain a generic executor. Example: 'Must be a valid GraphQL query string using operation names from the supported list: addProduct, getProductById, getAllProducts. Do not attempt other operations.'
• Enhance error messages with recovery guidance. Instead of 'GraphQL execution failed: ...', return specific hints like 'Product not found with ID "xyz". Check the ID format or call list_products() to see available products.' or 'Invalid ProductInput: required field "price" missing, must be a positive number.'
• Add constraints to the variables parameter description: 'Optional. Object keys must match variable names in the query. Values must match declared variable types in the GraphQL operation.'
• Implement input validation before executing the GraphQL query. Reject queries that do not start with 'query' or 'mutation' keywords, or that reference unknown operations.