{
    "action": "tool_call",
    "reasoning": "Profile the candidate grouping keys (company_name, stock_name, ticker suffix) and their coverage in one query.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT COUNT(*) AS n_rows, COUNT(DISTINCT company_name) AS n_companies, COUNT(DISTINCT stock_name) AS n_tickers, COUNT(DISTINCT CASE WHEN stock_name LIKE '%.%' THEN regexp_extract(stock_name, '\\.([A-Za-z]+)$', 1) END) AS n_suffixes, SUM(CASE WHEN stock_name LIKE '%.%' THEN 1 ELSE 0 END) AS rows_with_suffix, MIN(date) AS min_date, MAX(date) AS max_date, MIN(close) AS min_close, MEDIAN(close) AS med_close, MAX(close) AS max_close, MEDIAN(volume) AS med_volume FROM raw.semi_conductor_se",
        "purpose": "Profile candidate segmentation keys",
        "source": "raw"
    }
}