{
    "action": "tool_call",
    "reasoning": "Check whether the only timestamp column (_ingestion_timestamp) carries real time variation, or is just load metadata.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT COUNT(*) AS n, COUNT(DISTINCT _ingestion_timestamp) AS distinct_ts, MIN(_ingestion_timestamp) AS min_ts, MAX(_ingestion_timestamp) AS max_ts, COUNT(DISTINCT _batch_id) AS batches, COUNT(DISTINCT _source_file) AS files FROM raw.bedtime_screentime_sleep_debt",
        "purpose": "Check whether the only timestamp column carries any real time variation",
        "source": "raw"
    }
}