{
    "action": "tool_call",
    "reasoning": "No evidence is visible in this turn, so I'll recompute the key correlations and the blue-light group comparison in one query before answering.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT COUNT(*) AS n, ROUND(CORR(bedtime_phone_minutes, sleep_latency_min),3) AS phone_latency, ROUND(CORR(bedtime_phone_minutes, next_day_fatigue_score),3) AS phone_fatigue, ROUND(CORR(bedtime_phone_minutes, total_sleep_hours),3) AS phone_sleep_hours, ROUND(CORR(blue_light_filter_active, sleep_latency_min),3) AS filter_latency, ROUND(CORR(blue_light_filter_active, total_sleep_hours),3) AS filter_sleep_hours, ROUND(CORR(screen_brightness_pct, sleep_latency_min),3) AS brightness_latency, ROUND(CORR(caffeine_post_5pm_mg, total_sleep_hours),3) AS caffeine_sleep_hours, ROUND(CORR(caffeine_post_5pm_mg, deep_sleep_pct),3) AS caffeine_deep, ROUND(CORR(caffeine_post_5pm_mg, sleep_latency_min),3) AS caffeine_latency, ROUND(CORR(caffeine_post_5pm_mg, next_day_fatigue_score),3) AS caffeine_fatigue, ROUND(CORR(physical_activity_min, total_sleep_hours),3) AS activity_sleep_hours, ROUND(CORR(physical_activity_min, next_day_fatigue_score),3) AS activity_fatigue FROM raw.bedtime_screentime_sleep_debt",
        "purpose": "Verify the correlations between bedtime behaviours and sleep outcomes",
        "source": "raw"
    }
}