curl -X POST https://api.thinnest.ai/knowledge/test-retrieval \
  -H "Authorization: Bearer $THINNESTAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "agent_id": "ag_c47e7c97_b2f2",
  "query": "What is your return policy?",
  "top_k": 5
}'

{
  "results": [
    {
      "content": "Our return policy allows returns within 30 days of purchase. Items must be unused and in original packaging.",
      "source_name": "Return Policy",
      "source_type": "text",
      "similarity_score": 0.94,
      "chunk_index": 0
    },
    {
      "content": "Refunds are processed within 5-7 business days after we receive the returned item.",
      "source_name": "Return Policy",
      "source_type": "text",
      "similarity_score": 0.87,
      "chunk_index": 1
    },
    {
      "content": "Exchanges can be made for items of equal or lesser value. Price differences are refunded to the original payment method.",
      "source_name": "FAQ Document",
      "source_type": "text",
      "similarity_score": 0.72,
      "chunk_index": 3
    }
  ],
  "query": "What is your return policy?",
  "total_results": 3
}