{
    "action": "tool_call",
    "reasoning": "The question asks for natural segmentation/grouping of records. I've already seen the dataset overview showing 51 tables with different roles (dimension, path, etc.) and the dominant tables. I should explore the actual business entities and their natural groupings. The evidence shows datasets (109), batches (304), analysis_runs (116), and massive operational logs. Let me check what natural dimensions exist for segmenting the core entities - starting with datasets since they're the fundamental unit being analyzed.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT source, COUNT(*) as dataset_count, COUNT(DISTINCT current_batch_id) as batches_used, SUM(CASE WHEN status = 'ready' THEN 1 ELSE 0 END) as ready_count, SUM(CASE WHEN status = 'deleted' THEN 1 ELSE 0 END) as deleted_count FROM raw.datasets GROUP BY source ORDER BY dataset_count DESC",
        "purpose": "Segment datasets by their source to understand natural groupings of the core entity"
    }
}