feat(voyageai): expose token usage in rerank results

libs/voyageai/langchain_voyageai/rerank.py

@@ -114,15 +114,18 @@ def compress_documents(
 
         Returns:
             A sequence of compressed documents in relevance_score order.
+            Each document's metadata includes 'relevance_score' and 'total_tokens'.
         """
         if len(documents) == 0:
             return []
 
+        rerank_result = self._rerank(documents, query)
         compressed = []
-        for res in self._rerank(documents, query).results:
+        for res in rerank_result.results:
             doc = documents[res.index]
             doc_copy = Document(doc.page_content, metadata=deepcopy(doc.metadata))
             doc_copy.metadata["relevance_score"] = res.relevance_score
+            doc_copy.metadata["total_tokens"] = rerank_result.total_tokens
             compressed.append(doc_copy)
         return compressed
 
@@ -142,14 +145,17 @@ async def acompress_documents(
 
         Returns:
             A sequence of compressed documents in relevance_score order.
+            Each document's metadata includes 'relevance_score' and 'total_tokens'.
         """
         if len(documents) == 0:
             return []
 
+        rerank_result = await self._arerank(documents, query)
         compressed = []
-        for res in (await self._arerank(documents, query)).results:
+        for res in rerank_result.results:
             doc = documents[res.index]
             doc_copy = Document(doc.page_content, metadata=deepcopy(doc.metadata))
             doc_copy.metadata["relevance_score"] = res.relevance_score
+            doc_copy.metadata["total_tokens"] = rerank_result.total_tokens
             compressed.append(doc_copy)
         return compressed

libs/voyageai/tests/integration_tests/test_rerank.py

@@ -38,6 +38,10 @@ def test_sync() -> None:
         query="When is the Apple's conference call scheduled?", documents=documents
     )
     assert len(doc_list) == len(result)
+    for doc in result:
+        assert "total_tokens" in doc.metadata
+        assert isinstance(doc.metadata["total_tokens"], int)
+        assert doc.metadata["total_tokens"] > 0
 
 
 async def test_async() -> None:
@@ -66,3 +70,7 @@ async def test_async() -> None:
         query="When is the Apple's conference call scheduled?", documents=documents
     )
     assert len(doc_list) == len(result)
+    for doc in result:
+        assert "total_tokens" in doc.metadata
+        assert isinstance(doc.metadata["total_tokens"], int)
+        assert doc.metadata["total_tokens"] > 0

libs/voyageai/tests/unit_tests/test_rerank.py

@@ -53,12 +53,12 @@ def test_rerank_unit_test(mocker: Any) -> None:
         Document(
             page_content="Photosynthesis in plants converts light energy into "
             "glucose and produces essential oxygen.",
-            metadata={"relevance_score": 0.9},
+            metadata={"relevance_score": 0.9, "total_tokens": 255},
         ),
         Document(
             page_content="The Mediterranean diet emphasizes fish, olive oil, and "
             "vegetables, believed to reduce chronic diseases.",
-            metadata={"relevance_score": 0.8},
+            metadata={"relevance_score": 0.8, "total_tokens": 255},
         ),
     ]