Single tool 'mysql_query' has critical definition gaps. Input schema present but lacks parameter descriptions entirely. Tool description is generic (41 chars) and does not explain WHEN to use it, what it returns, or that it modifies state. No output schema documented. No error handling guidance. Parameter 'sql' has no description, LLMs cannot infer whether to pass raw SQL, parameterized queries, or what formats are safe. No mention of transaction behavior, rollback semantics, or destructive operation warnings despite WRITE risk classification.

• Expand tool description to 100-200 chars: 'Execute SQL queries (SELECT, INSERT, UPDATE, DELETE) against MySQL database. Queries run in transactions with automatic rollback on error. Returns structured result rows. Use for data retrieval and modifications.'
• Add 'sql' parameter description: 'SQL query string. Supports SELECT, INSERT, UPDATE, DELETE. Parameterized queries not supported, pass raw SQL only. Queries execute in a transaction and auto-rollback on error.'
• Document output schema: 'Returns {content: [{type: "text", text: JSON.stringify(rows)}], isError: boolean}. For SELECT: array of row objects. For INSERT/UPDATE/DELETE: affected row count.'
• Add error handling examples: 'If query syntax is invalid, returns error with SQL message. If table not found, suggests available tables. If connection fails, advises checking MYSQL_HOST/MYSQL_PORT env vars.'
• Implement dry-run parameter: Add optional 'dry_run: boolean' to preview query results without committing. For destructive ops, default to dry_run=true and require explicit dry_run=false.