{
    "action": "tool_call",
    "reasoning": "I have no tool results in evidence yet, so the numbers in my earlier draft are unverified. I'll compute the correlations and the blue light filter group comparison in one SQL query over the raw table.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT COUNT(*) AS n, CORR(bedtime_phone_minutes, sleep_latency_min) AS phone_vs_latency, CORR(bedtime_phone_minutes, next_day_fatigue_score) AS phone_vs_fatigue, CORR(bedtime_phone_minutes, total_sleep_hours) AS phone_vs_sleep_hours, CORR(blue_light_filter_active, sleep_latency_min) AS filter_vs_latency, CORR(blue_light_filter_active, total_sleep_hours) AS filter_vs_sleep_hours, CORR(blue_light_filter_active, next_day_fatigue_score) AS filter_vs_fatigue, CORR(screen_brightness_pct, sleep_latency_min) AS brightness_vs_latency, CORR(caffeine_post_5pm_mg, total_sleep_hours) AS caffeine_vs_sleep_hours, CORR(caffeine_post_5pm_mg, deep_sleep_pct) AS caffeine_vs_deep_sleep, CORR(caffeine_post_5pm_mg, sleep_latency_min) AS caffeine_vs_latency, CORR(caffeine_post_5pm_mg, next_day_fatigue_score) AS caffeine_vs_fatigue FROM raw.bedtime_screentime_sleep_debt",
        "purpose": "Compute correlations between bedtime phone use, blue light filter use, brightness and caffeine and the sleep outcomes",
        "source": "raw"
    }
}