RERANKER Spans
Purpose
RERANKER spans represent reordering of retrieved documents (Cohere Rerank, cross-encoder models).
Required Attributes
| Attribute |
Type |
Description |
Required |
openinference.span.kind |
String |
Must be "RERANKER" |
Yes |
Attribute Reference
Reranker Parameters
| Attribute |
Type |
Description |
reranker.model_name |
String |
Reranker model identifier |
reranker.query |
String |
Query used for reranking |
reranker.top_k |
Integer |
Number of documents to return |
Input Documents
| Attribute Pattern |
Type |
Description |
reranker.input_documents.{i}.document.id |
String |
Input document ID |
reranker.input_documents.{i}.document.content |
String |
Input document content |
reranker.input_documents.{i}.document.score |
Float |
Original retrieval score |
reranker.input_documents.{i}.document.metadata |
String (JSON) |
Document metadata |
Output Documents
| Attribute Pattern |
Type |
Description |
reranker.output_documents.{i}.document.id |
String |
Output document ID (reordered) |
reranker.output_documents.{i}.document.content |
String |
Output document content |
reranker.output_documents.{i}.document.score |
Float |
New reranker score |
reranker.output_documents.{i}.document.metadata |
String (JSON) |
Document metadata |
Score Comparison
Input scores (from retriever) vs. output scores (from reranker):
{
"reranker.input_documents.0.document.id": "doc_A",
"reranker.input_documents.0.document.score": 0.7,
"reranker.input_documents.1.document.id": "doc_B",
"reranker.input_documents.1.document.score": 0.9,
"reranker.output_documents.0.document.id": "doc_B",
"reranker.output_documents.0.document.score": 0.95,
"reranker.output_documents.1.document.id": "doc_A",
"reranker.output_documents.1.document.score": 0.85
}
In this example:
- Input: doc_B (0.9) ranked higher than doc_A (0.7)
- Output: doc_B still highest but both scores increased
- Reranker confirmed retriever's ordering but refined scores
Examples
Complete Reranking Example
{
"openinference.span.kind": "RERANKER",
"reranker.model_name": "cohere-rerank-v2",
"reranker.query": "What is machine learning?",
"reranker.top_k": 2,
"reranker.input_documents.0.document.id": "doc_123",
"reranker.input_documents.0.document.content": "Machine learning is a subset...",
"reranker.input_documents.1.document.id": "doc_456",
"reranker.input_documents.1.document.content": "Supervised learning algorithms...",
"reranker.input_documents.2.document.id": "doc_789",
"reranker.input_documents.2.document.content": "Neural networks are...",
"reranker.output_documents.0.document.id": "doc_456",
"reranker.output_documents.0.document.content": "Supervised learning algorithms...",
"reranker.output_documents.0.document.score": 0.95,
"reranker.output_documents.1.document.id": "doc_123",
"reranker.output_documents.1.document.content": "Machine learning is a subset...",
"reranker.output_documents.1.document.score": 0.88
}
