{
    "action": "tool_call",
    "reasoning": "The question asks about natural segmentation opportunities across the dataset. I've already seen the semantic_role x rough_kind breakdown for columns_catalog (the dominant table), but I should explore other major tables to identify meaningful grouping dimensions. The batches table showed status segmentation (ready/completed/running), and I should check job_logs (the second-largest table) and llm_calls for their natural groupings. Let me start with job_logs to see what dimensions it offers.",
    "tool": "inspect_columns",
    "args": {
        "table": "job_logs",
        "columns": [
            "job_id",
            "phase",
            "status",
            "job_type",
            "dataset_id",
            "tenant_id"
        ]
    }
}