{
    "action": "tool_call",
    "reasoning": "The evidence shows geographic data exists in ip_geo (city, country, country_code, region) and nia_messages (author_geo). The step-3 result shows a distribution but has many null countries (empty first column) and appears to be from nia_messages.author_geo based on the small counts. I need to check the ip_geo table's distribution to see the full geographic coverage, and also understand what nia_messages.author_geo represents versus the ip_geo table's structured fields.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT country, region, city, COUNT(*) as record_count FROM raw.ip_geo WHERE country IS NOT NULL GROUP BY country, region, city ORDER BY record_count DESC LIMIT 50",
        "purpose": "Get the geographic distribution from the ip_geo table to understand location coverage",
        "source": "raw"
    }
}