{
    "action": "tool_call",
    "reasoning": "The earlier draft cited column-metadata queries that are not in my evidence, so I will run one to ground the column types and null counts before answering.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT column_name, phys_type, semantic_role, null_count, distinct_count, min_value, max_value FROM analytics.column_overview WHERE table_name = 'AI_Usage_and_Impact_on_Students_and_Professionals'",
        "purpose": "Profile all 23 columns: type, role, nulls, distinct counts, and range",
        "source": "raw"
    }
}