{
    "action": "tool_call",
    "reasoning": "My previous draft cited correlations and group averages without a tool result behind them, so I'm discarding it. First I'll compute the correlations and the blue-light filter comparison in one 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(screen_brightness_pct, sleep_latency_min) AS brightness_vs_latency, CORR(physical_activity_min, total_sleep_hours) AS activity_vs_sleep_hours, CORR(physical_activity_min, next_day_fatigue_score) AS activity_vs_fatigue, 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, CORR(caffeine_post_5pm_mg, sleep_latency_min) AS caffeine_vs_latency FROM raw.bedtime_screentime_sleep_debt",
        "purpose": "Compute correlations between bedtime behaviours and sleep outcomes",
        "source": "raw"
    }
}