```json { "action": "tool_call", "reasoning": "I need to find all columns with missing values and calculate the percentage missing. I'll query the analytics.column_overview metadata table which contains null_count for each column, and join with analytics.table_overview to get row counts for percentage calculation.", "tool": "query_sql", "args": { "sql": "SELECT co.table_name, co.column_name, co.null_count, ROUND(100.0 * co.null_count / to.row_count, 2) AS pct_missing FROM analytics.column_overview co JOIN analytics.table_overview to ON co.table_name = to.table_name WHERE co.null_count > 0 ORDER BY pct_missing DESC, co.table_name, co.column_name", "purpose": "Find all columns with missing values and calculate the percentage missing", "source": "raw" } } ```