The MySQL DB Reader server demonstrates solid definition quality with consistent naming, clear descriptions, and well-structured schemas across all 6 tools. All tools follow verb_noun naming conventions (mysql_list_*, mysql_get_*, mysql_preview_*, mysql_query, mysql_explain_*). Descriptions are substantive and provide context for when/why to use each tool. Parameter schemas are complete with type definitions and constraints. However, there are gaps in output schema documentation and error handling guidance that prevent a higher score.

• Document output schemas for all tools. Example for mysql_list_databases: 'Returns an array of objects with fields: {database: string, character_set: string, collation: string}'. For mysql_query: 'Returns array of objects where keys are column names and values are typed (strings, numbers, nulls, dates).'
• Add error recovery guidance to descriptions and error messages. Instead of 'Invalid database identifier', return 'Invalid database name. Identifiers must contain only alphanumerics and underscores (A-Za-z0-9_). Available databases: [list]'. Call mysql_list_databases() first if unsure.
• State result limits explicitly in descriptions. mysql_list_tables: 'Returns all tables in the database. If >1000 tables, consider filtering with schema patterns or calling mysql_get_table_schema on specific tables instead.' mysql_preview_table: 'The limit parameter must be between 1 and 1000 rows.'
• Expose timeout in tool descriptions: 'Queries that exceed 30 seconds will timeout and the connection will be destroyed. For long-running analysis, break into smaller queries using LIMIT or add WHERE clauses to reduce result sets.'
• Provide chaining hints in descriptions. E.g., mysql_list_databases description should say: 'Use this first to discover available databases. Then call mysql_list_tables with the database name to explore tables.'
• Consider adding a mysql_search_tables tool that accepts a pattern/substring to filter by table name, reducing the need for LLMs to parse large unstructured table lists.