{
    "action": "tool_call",
    "reasoning": "No query results are in evidence yet, so I can't cite the segment numbers. I'll compute the Overall_Impact segment profile directly in one query.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT Overall_Impact, COUNT(*) AS students, ROUND(100.0*COUNT(*)/SUM(COUNT(*)) OVER (),1) AS pct_students, ROUND(AVG(Daily_Usage_Hours),2) AS avg_daily_hours, ROUND(AVG(Weekend_Extra_Hours),2) AS avg_weekend_extra, ROUND(AVG(Sleep_Duration_Hours),2) AS avg_sleep_hours, ROUND(AVG(Sleep_Quality_Score),2) AS avg_sleep_quality, ROUND(AVG(Perceived_Stress_Score),2) AS avg_stress, ROUND(AVG(Mental_Health_Index),1) AS avg_mental_health, ROUND(AVG(Academic_Performance_GPA),2) AS avg_gpa, ROUND(100.0*AVG(CASE WHEN Late_Night_Usage THEN 1 ELSE 0 END),1) AS pct_late_night FROM raw.Social_media_impact_on_life GROUP BY Overall_Impact ORDER BY avg_daily_hours",
        "purpose": "Profile segments defined by Overall_Impact across usage, sleep, stress, mental health, GPA and late-night use",
        "source": "raw"
    }
}