{
    "action": "tool_call",
    "reasoning": "No query results are in evidence yet, so I can't cite the numbers from my earlier draft. I'll recompute the cost and usage correlations against the outcomes in one query. Several of these columns are VARCHAR, so I'll use TRY_CAST.",
    "tool": "query_sql",
    "args": {
        "sql": "WITH t AS (SELECT TRY_CAST(Monthly_AI_Cost AS DOUBLE) AS cost, TRY_CAST(AI_Usage_Hours_Per_Day AS DOUBLE) AS hrs, TRY_CAST(Time_Saved_Hours_Per_Week AS DOUBLE) AS saved, Productivity_Score AS prod, Satisfaction_Score AS sat, Accuracy_Rating AS acc FROM raw.AI_Usage_and_Impact_on_Students_and_Professionals) SELECT COUNT(*) AS n_rows, COUNT(cost) AS n_cost, SUM(CASE WHEN cost = 0 THEN 1 ELSE 0 END) AS n_free, SUM(CASE WHEN cost > 0 THEN 1 ELSE 0 END) AS n_paid, CORR(cost, prod) AS cost_prod, CORR(cost, sat) AS cost_sat, CORR(cost, acc) AS cost_acc, CORR(cost, saved) AS cost_saved, CORR(hrs, saved) AS hrs_saved, CORR(hrs, prod) AS hrs_prod, CORR(hrs, sat) AS hrs_sat, CORR(prod, sat) AS prod_sat, AVG(CASE WHEN cost = 0 THEN prod END) AS free_prod, AVG(CASE WHEN cost > 0 THEN prod END) AS paid_prod, AVG(CASE WHEN cost = 0 THEN sat END) AS free_sat, AVG(CASE WHEN cost > 0 THEN sat END) AS paid_sat, AVG(CASE WHEN cost = 0 THEN acc END) AS free_acc, AVG(CASE WHEN cost > 0 THEN acc END) AS paid_acc, AVG(CASE WHEN cost = 0 THEN saved END) AS free_saved, AVG(CASE WHEN cost > 0 THEN saved END) AS paid_saved FROM t",
        "purpose": "Compute correlations of AI cost and usage with outcomes, plus free vs paid group means",
        "source": "raw"
    }
}