{
    "action": "tool_call",
    "reasoning": "I need to find the time period covered by the dataset. I will query the analytics.column_overview to find the minimum and maximum values of date/timestamp columns across all tables.",
    "tool": "query_sql",
    "args": {
        "purpose": "Find the overall time period covered by the dataset by looking at date/timestamp columns.",
        "source": "raw",
        "sql": "SELECT table_name, column_name, min_value, max_value, phys_type FROM analytics.column_overview WHERE phys_type IN ('TIMESTAMP', 'DATE', 'DATETIME', 'TIMESTAMP WITH TIME ZONE') OR rough_kind IN ('date', 'timestamp') OR semantic_role LIKE '%date%' OR semantic_role LIKE '%time%' ORDER BY min_value ASC NULLS LAST LIMIT 20;"
    }
}