{
    "action": "tool_call",
    "reasoning": "I've checked the two largest tables (columns_catalog and job_logs) for exact duplicates and found none. Now I need to check llm_calls (49,360 rows) for duplicates. The natural key would be created_at + purpose + model + dataset_id + job_id, but since some of these have nulls, I'll check for duplicates on the combination of fields that should uniquely identify an LLM call.",
    "tool": "query_sql",
    "args": {
        "sql": "SELECT created_at, purpose, model, provider, dataset_id, job_id, COUNT(*) as duplicate_count FROM raw.llm_calls GROUP BY created_at, purpose, model, provider, dataset_id, job_id HAVING COUNT(*) > 1 ORDER BY duplicate_count DESC LIMIT 50",
        "purpose": "Check for duplicate LLM calls based on natural key fields",
        "source": "raw"
    }
}