{
    "action": "tool_call",
    "reasoning": "The evidence block is empty here, so the numbers in my earlier draft aren't backed by any result I can see. I'll run one profiling query to ground the data-quality review.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT COUNT(*) AS n_rows, COUNT(DISTINCT Student_ID) AS distinct_ids, COUNT(Student_ID) AS nn_id, COUNT(Academic_Performance_GPA) AS nn_gpa, COUNT(Perceived_Stress_Score) AS nn_stress, COUNT(Sleep_Duration_Hours) AS nn_sleep, COUNT(Mental_Health_Index) AS nn_mh, MIN(Age) AS min_age, MAX(Age) AS max_age, MIN(Daily_Usage_Hours) AS min_use, MAX(Daily_Usage_Hours) AS max_use, MIN(Sleep_Duration_Hours) AS min_sleep, MAX(Sleep_Duration_Hours) AS max_sleep, MIN(Sleep_Quality_Score) AS min_sq, MAX(Sleep_Quality_Score) AS max_sq, MIN(Mental_Health_Index) AS min_mh, MAX(Mental_Health_Index) AS max_mh, MIN(Perceived_Stress_Score) AS min_stress, MAX(Perceived_Stress_Score) AS max_stress, MIN(Academic_Performance_GPA) AS min_gpa, MAX(Academic_Performance_GPA) AS max_gpa, MIN(Weekend_Extra_Hours) AS min_wk, MAX(Weekend_Extra_Hours) AS max_wk, SUM(CASE WHEN Daily_Usage_Hours + Sleep_Duration_Hours > 20 THEN 1 ELSE 0 END) AS time_over_20, SUM(CASE WHEN Academic_Performance_GPA IS NULL THEN 1 ELSE 0 END) AS gpa_nulls, SUM(CASE WHEN Perceived_Stress_Score IS NULL THEN 1 ELSE 0 END) AS stress_nulls FROM raw.Social_media_impact_on_life",
        "purpose": "Profile keys, null counts, ranges and impossible time allocations in one query for the data-quality review",
        "source": "raw"
    }
}