{
    "action": "tool_call",
    "reasoning": "I need to check for duplicate rows across the dataset. The card shows 43 tables with over 2M rows total. I'll start by checking the largest tables for exact duplicates. The columns_catalog table (1.5M rows, 75% of data) is the dominant table. I already confirmed no duplicates exist when grouping by tables_catalog_id + column_name + ordinal (step-2 returned 0 rows). Now I should check job_logs (303K rows, 15% of data) and a few other significant tables. I'll write a query to find duplicate rows in job_logs by checking if any combination of key fields appears more than once.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT job_id, dataset_id, ts, level, event_type, source_module, message, COUNT(*) as duplicate_count FROM raw.job_logs GROUP BY job_id, dataset_id, ts, level, event_type, source_module, message HAVING COUNT(*) > 1 ORDER BY duplicate_count DESC LIMIT 20",
        "purpose": "Find duplicate rows in job_logs table by grouping on key identifying fields"
    }
}