diff --git a/.github/workflows/ci-unit-tests.yml b/.github/workflows/ci-unit-tests.yml
index 47ea37872..a353de3a7 100644
--- a/.github/workflows/ci-unit-tests.yml
+++ b/.github/workflows/ci-unit-tests.yml
@@ -139,9 +139,15 @@ jobs:
             rm -rf $dir/.tox
           }
 
-          run_itests libs/colbert
-          run_itests libs/langchain
-          run_itests libs/llamaindex
+          if [[ "true" == "${{ needs.preconditions.outputs.libs_colbert }}" ]]; then
+            run_itests libs/colbert
+          fi
+          if [[ "true" == "${{ needs.preconditions.outputs.libs_langchain }}" ]]; then
+            run_itests libs/langchain
+          fi
+          if [[ "true" == "${{ needs.preconditions.outputs.libs_llamaindex }}" ]]; then
+            run_itests libs/llamaindex
+          fi
 
       - name: Cleanup AstraDB
         uses: nicoloboschi/cleanup-astradb@v1
diff --git a/libs/knowledge-store/ragstack_knowledge_store/graph_store.py b/libs/knowledge-store/ragstack_knowledge_store/graph_store.py
index 0b5858e22..f43dcb9a5 100644
--- a/libs/knowledge-store/ragstack_knowledge_store/graph_store.py
+++ b/libs/knowledge-store/ragstack_knowledge_store/graph_store.py
@@ -8,6 +8,7 @@
     NamedTuple,
     Optional,
     Sequence,
+    Set,
     Tuple,
 )
 
@@ -18,7 +19,7 @@
 from .concurrency import ConcurrentQueries
 from .content import Kind
 from .embedding_model import EmbeddingModel
-from .link_tag import get_link_tags
+from .links import Link
 from .math import cosine_similarity
 
 CONTENT_ID = "content_id"
@@ -31,8 +32,9 @@ class Node:
     id: Optional[str] = None
     """Unique ID for the node. Will be generated by the GraphStore if not set."""
     metadata: dict = field(default_factory=dict)
-    """Metadata for the node. May contain information used to link this node 
-    with other nodes."""
+    """Metadata for the node."""
+    links: Set[Link] = field(default_factory=set)
+    """Links for the node."""
 
 
 @dataclass
@@ -328,11 +330,13 @@ def add_nodes(
     ) -> Iterable[str]:
         texts = []
         metadatas = []
+        nodes_links: List[Set[Link]] = []
         for node in nodes:
             if not isinstance(node, TextNode):
                 raise ValueError("Only adding TextNode is supported at the moment")
             texts.append(node.text)
             metadatas.append(node.metadata)
+            nodes_links.append(node.links)
 
         text_embeddings = self._embedding.embed_texts(texts)
 
@@ -343,8 +347,8 @@ def add_nodes(
 
         # Step 1: Add the nodes, collecting the tags and new sources / targets.
         with self._concurrent_queries() as cq:
-            tuples = zip(texts, text_embeddings, metadatas)
-            for text, text_embedding, metadata in tuples:
+            tuples = zip(texts, text_embeddings, metadatas, nodes_links)
+            for text, text_embedding, metadata, links in tuples:
                 if CONTENT_ID not in metadata:
                     metadata[CONTENT_ID] = secrets.token_hex(8)
                 id = metadata[CONTENT_ID]
@@ -353,20 +357,22 @@ def add_nodes(
                 link_to_tags = set()  # link to these tags
                 link_from_tags = set()  # link from these tags
 
-                for tag in get_link_tags(metadata):
-                    tag_str = f"{tag.kind}:{tag.tag}"
-                    if tag.direction == "incoming" or tag.direction == "bidir":
-                        # An incom`ing link should be linked *from* nodes with the given tag.
-                        link_from_tags.add(tag_str)
-                        tag_to_new_targets.setdefault(tag_str, dict())[id] = (
-                            tag.kind,
-                            text_embedding,
-                        )
-                    if tag.direction == "outgoing" or tag.direction == "bidir":
-                        link_to_tags.add(tag_str)
-                        tag_to_new_sources.setdefault(tag_str, list()).append(
-                            (tag.kind, id)
-                        )
+                for tag in links:
+                    if hasattr(tag, "tag"):
+                        tag_str = f"{tag.kind}:{tag.tag}"
+                        if tag.direction == "incoming" or tag.direction == "bidir":
+                            # An incoming link should be linked *from* nodes with the
+                            # given tag.
+                            link_from_tags.add(tag_str)
+                            tag_to_new_targets.setdefault(tag_str, dict())[id] = (
+                                tag.kind,
+                                text_embedding,
+                            )
+                        if tag.direction == "outgoing" or tag.direction == "bidir":
+                            link_to_tags.add(tag_str)
+                            tag_to_new_sources.setdefault(tag_str, list()).append(
+                                (tag.kind, id)
+                            )
 
                 cq.execute(
                     self._insert_passage,
diff --git a/libs/knowledge-store/ragstack_knowledge_store/link_tag.py b/libs/knowledge-store/ragstack_knowledge_store/link_tag.py
deleted file mode 100644
index 28096e422..000000000
--- a/libs/knowledge-store/ragstack_knowledge_store/link_tag.py
+++ /dev/null
@@ -1,54 +0,0 @@
-from dataclasses import dataclass
-from typing import Literal, Dict, Any, Set
-
-
-@dataclass(frozen=True)
-class _LinkTag:
-    kind: str
-    tag: str
-    direction: Literal["incoming", "outgoing", "bidir"]
-
-
-@dataclass(frozen=True)
-class LinkTag(_LinkTag):
-    def __init__(self, kind: str, tag: str, direction: str) -> None:
-        if self.__class__ == LinkTag:
-            raise TypeError("Abstract class LinkTag cannot be instantiated")
-        super().__init__(kind, tag, direction)
-
-
-@dataclass(frozen=True)
-class OutgoingLinkTag(LinkTag):
-    def __init__(self, kind: str, tag: str) -> None:
-        super().__init__(kind=kind, tag=tag, direction="outgoing")
-
-
-@dataclass(frozen=True)
-class IncomingLinkTag(LinkTag):
-    def __init__(self, kind: str, tag: str) -> None:
-        super().__init__(kind=kind, tag=tag, direction="incoming")
-
-
-@dataclass(frozen=True)
-class BidirLinkTag(LinkTag):
-    def __init__(self, kind: str, tag: str) -> None:
-        super().__init__(kind=kind, tag=tag, direction="bidir")
-
-
-LINK_TAGS = "link_tags"
-
-
-def get_link_tags(doc_or_md: Dict[str, Any]) -> Set[LinkTag]:
-    """Get the link-tag set from a document or metadata.
-
-    Args:
-        doc_or_md: The document or metadata to get the link tags from.
-
-    Returns:
-        The set of link tags from the document or metadata.
-    """
-    link_tags = doc_or_md.setdefault(LINK_TAGS, set())
-    if not isinstance(link_tags, Set):
-        link_tags = set(link_tags)
-        doc_or_md[LINK_TAGS] = link_tags
-    return link_tags
diff --git a/libs/knowledge-store/ragstack_knowledge_store/links.py b/libs/knowledge-store/ragstack_knowledge_store/links.py
new file mode 100644
index 000000000..05a9a90dd
--- /dev/null
+++ b/libs/knowledge-store/ragstack_knowledge_store/links.py
@@ -0,0 +1,37 @@
+from dataclasses import dataclass
+from typing import Literal
+
+
+@dataclass(frozen=True)
+class Link:
+    kind: str
+    direction: Literal["incoming", "outgoing", "bidir"]
+
+    def __post_init__(self):
+        if self.__class__ in [Link, LinkTag]:
+            raise TypeError(
+                f"Abstract class {self.__class__.__name__} cannot be instantiated"
+            )
+
+
+@dataclass(frozen=True)
+class LinkTag(Link):
+    tag: str
+
+
+@dataclass(frozen=True)
+class OutgoingLinkTag(LinkTag):
+    def __init__(self, kind: str, tag: str) -> None:
+        super().__init__(kind=kind, tag=tag, direction="outgoing")
+
+
+@dataclass(frozen=True)
+class IncomingLinkTag(LinkTag):
+    def __init__(self, kind: str, tag: str) -> None:
+        super().__init__(kind=kind, tag=tag, direction="incoming")
+
+
+@dataclass(frozen=True)
+class BidirLinkTag(LinkTag):
+    def __init__(self, kind: str, tag: str) -> None:
+        super().__init__(kind=kind, tag=tag, direction="bidir")
diff --git a/libs/langchain/ragstack_langchain/graph_store/base.py b/libs/langchain/ragstack_langchain/graph_store/base.py
index c28696cf8..9e7249707 100644
--- a/libs/langchain/ragstack_langchain/graph_store/base.py
+++ b/libs/langchain/ragstack_langchain/graph_store/base.py
@@ -10,6 +10,7 @@
     Iterator,
     List,
     Optional,
+    Set,
 )
 
 from langchain_core.callbacks import (
@@ -20,7 +21,9 @@
 from langchain_core.load import Serializable
 from langchain_core.runnables import run_in_executor
 from langchain_core.vectorstores import VectorStore, VectorStoreRetriever
-from pydantic import Field
+from langchain_core.pydantic_v1 import Field
+
+from ragstack_langchain.graph_store.links import METADATA_LINKS_KEY, Link
 
 
 def _has_next(iterator: Iterator) -> None:
@@ -36,8 +39,9 @@ class Node(Serializable):
     id: Optional[str]
     """Unique ID for the node. Will be generated by the GraphStore if not set."""
     metadata: dict = Field(default_factory=dict)
-    """Metadata for the node. May contain information used to link this node
-    with other nodes."""
+    """Metadata for the node."""
+    links: Set[Link] = Field(default_factory=set)
+    """Links associated with the node."""
 
 
 class TextNode(Node):
@@ -54,17 +58,20 @@ def _texts_to_nodes(
     ids_it = iter(ids) if ids else None
     for text in texts:
         try:
-            _metadata = next(metadatas_it) if metadatas_it else {}
+            _metadata = next(metadatas_it).copy() if metadatas_it else {}
         except StopIteration:
             raise ValueError("texts iterable longer than metadatas")
         try:
             _id = next(ids_it) if ids_it else None
         except StopIteration:
             raise ValueError("texts iterable longer than ids")
+
+        links = _metadata.pop(METADATA_LINKS_KEY, set())
         yield TextNode(
             id=_id,
             metadata=_metadata,
             text=text,
+            links=links,
         )
     if ids and _has_next(ids_it):
         raise ValueError("ids iterable longer than texts")
@@ -81,10 +88,13 @@ def _documents_to_nodes(
             _id = next(ids_it) if ids_it else None
         except StopIteration:
             raise ValueError("documents iterable longer than ids")
+        metadata = doc.metadata.copy()
+        links = metadata.pop(METADATA_LINKS_KEY, set())
         yield TextNode(
             id=_id,
-            metadata=doc.metadata,
+            metadata=metadata,
             text=doc.page_content,
+            links=links,
         )
     if ids and _has_next(ids_it):
         raise ValueError("ids iterable longer than documents")
diff --git a/libs/langchain/ragstack_langchain/graph_store/cassandra.py b/libs/langchain/ragstack_langchain/graph_store/cassandra.py
index fe2fe5e63..93f7a8325 100644
--- a/libs/langchain/ragstack_langchain/graph_store/cassandra.py
+++ b/libs/langchain/ragstack_langchain/graph_store/cassandra.py
@@ -101,7 +101,9 @@ def add_nodes(
             if not isinstance(node, TextNode):
                 raise ValueError("Only adding TextNode is supported at the moment")
             _nodes.append(
-                graph_store.TextNode(id=node.id, text=node.text, metadata=node.metadata)
+                graph_store.TextNode(
+                    id=node.id, text=node.text, metadata=node.metadata, links=node.links
+                )
             )
         return self.store.add_nodes(_nodes)
 
diff --git a/libs/langchain/ragstack_langchain/graph_store/extractors/edge_extractor.py b/libs/langchain/ragstack_langchain/graph_store/extractors/edge_extractor.py
index 5042edf95..d13e090f3 100644
--- a/libs/langchain/ragstack_langchain/graph_store/extractors/edge_extractor.py
+++ b/libs/langchain/ragstack_langchain/graph_store/extractors/edge_extractor.py
@@ -1,28 +1,25 @@
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
-from typing import Generic, Iterable, Iterator, Set, TypeVar
+from typing import Generic, Iterable, TypeVar
 
 from langchain_core.documents import Document
 from ragstack_knowledge_store._utils import strict_zip
-from ragstack_knowledge_store.link_tag import LinkTag
 
 InputT = TypeVar("InputT")
 
 
 class EdgeExtractor(ABC, Generic[InputT]):
     @abstractmethod
-    def extract_one(self, document: Document, input: InputT):
+    def extract_one(self, document: Document, input: InputT) -> None:
         """Add edges from each `input` to the corresponding documents.
 
         Args:
             document: Document to add the link tags to.
-            inputs: The input content to extract edges from.
+            input: The input content to extract edges from.
         """
 
-    def extract(
-        self, documents: Iterable[Document], inputs: Iterable[InputT]
-    ) -> Iterator[Set[LinkTag]]:
+    def extract(self, documents: Iterable[Document], inputs: Iterable[InputT]) -> None:
         """Add edges from each `input` to the corresponding documents.
 
         Args:
diff --git a/libs/langchain/ragstack_langchain/graph_store/extractors/html_link_edge_extractor.py b/libs/langchain/ragstack_langchain/graph_store/extractors/html_link_edge_extractor.py
index e3c257fcc..1e6ce9a21 100644
--- a/libs/langchain/ragstack_langchain/graph_store/extractors/html_link_edge_extractor.py
+++ b/libs/langchain/ragstack_langchain/graph_store/extractors/html_link_edge_extractor.py
@@ -1,6 +1,6 @@
 from langchain_core.documents import Document
-from ragstack_knowledge_store.link_tag import (
-    get_link_tags,
+from ragstack_langchain.graph_store.links import (
+    get_links,
     IncomingLinkTag,
     OutgoingLinkTag,
 )
@@ -68,7 +68,7 @@ def __init__(
             url_field: Name of the metadata field containing the URL
                 of the content. Defaults to "source".
             kind: The kind of edge to extract. Defaults to "hyperlink".
-            drop_fragmets: Whether fragments in URLs and links shoud be
+            drop_fragments: Whether fragments in URLs and links shoud be
                 dropped. Defaults to `True`.
         """
         try:
@@ -99,7 +99,7 @@ def extract_one(
 
         hrefs = _parse_hrefs(input, url, self.drop_fragments)
 
-        link_tags = get_link_tags(document.metadata)
+        link_tags = get_links(document)
         link_tags.add(IncomingLinkTag(kind=self._kind, tag=url))
         for url in hrefs:
             link_tags.add(OutgoingLinkTag(kind=self._kind, tag=url))
diff --git a/libs/langchain/ragstack_langchain/graph_store/links.py b/libs/langchain/ragstack_langchain/graph_store/links.py
new file mode 100644
index 000000000..32c9d3e06
--- /dev/null
+++ b/libs/langchain/ragstack_langchain/graph_store/links.py
@@ -0,0 +1,69 @@
+from dataclasses import dataclass
+from typing import Literal, Dict, Any, Set, Union
+
+from langchain_core.documents import Document
+
+
+@dataclass(frozen=True)
+class Link:
+    kind: str
+    direction: Literal["incoming", "outgoing", "bidir"]
+
+    def __post_init__(self):
+        if self.__class__ in [Link, LinkTag]:
+            raise TypeError(
+                f"Abstract class {self.__class__.__name__} cannot be instantiated"
+            )
+
+
+@dataclass(frozen=True)
+class LinkTag(Link):
+    tag: str
+
+
+@dataclass(frozen=True)
+class OutgoingLinkTag(LinkTag):
+    def __init__(self, kind: str, tag: str) -> None:
+        super().__init__(kind=kind, tag=tag, direction="outgoing")
+
+
+@dataclass(frozen=True)
+class IncomingLinkTag(LinkTag):
+    def __init__(self, kind: str, tag: str) -> None:
+        super().__init__(kind=kind, tag=tag, direction="incoming")
+
+
+@dataclass(frozen=True)
+class BidirLinkTag(LinkTag):
+    def __init__(self, kind: str, tag: str) -> None:
+        super().__init__(kind=kind, tag=tag, direction="bidir")
+
+
+METADATA_LINKS_KEY = "links"
+
+
+def get_links(doc_or_md: Union[Document, Dict[str, Any]]) -> Set[Link]:
+    """Get the links from a document or metadata.
+    Args:
+        doc_or_md: The metadata to get the link tags from.
+    Returns:
+        The set of link tags from the document or metadata.
+    """
+
+    if isinstance(doc_or_md, Document):
+        doc_or_md = doc_or_md.metadata
+
+    links = doc_or_md.setdefault(METADATA_LINKS_KEY, set())
+    if not isinstance(links, Set):
+        links = set(links)
+        doc_or_md[METADATA_LINKS_KEY] = links
+    return links
+
+
+def add_links(doc_or_md: Union[Document, Dict[str, Any]], *links: Link) -> None:
+    """Add links to the given metadata.
+    Args:
+        doc_or_md: The document or metadata to add the links to.
+        *links: The links to add to the metadata.
+    """
+    get_links(doc_or_md).update(links)
diff --git a/libs/langchain/tests/integration_tests/conftest.py b/libs/langchain/tests/integration_tests/conftest.py
index 64de5a383..3ba892efa 100644
--- a/libs/langchain/tests/integration_tests/conftest.py
+++ b/libs/langchain/tests/integration_tests/conftest.py
@@ -1,6 +1,10 @@
 import pytest
+from dotenv import load_dotenv
 from ragstack_tests_utils import AstraDBTestStore, LocalCassandraTestStore
 
+load_dotenv()
+
+
 status = {
     "local_cassandra_test_store": None,
     "astradb_test_store": None,
diff --git a/libs/langchain/tests/integration_tests/test_graph_store.py b/libs/langchain/tests/integration_tests/test_graph_store.py
index bf2c2e604..ce867522d 100644
--- a/libs/langchain/tests/integration_tests/test_graph_store.py
+++ b/libs/langchain/tests/integration_tests/test_graph_store.py
@@ -13,12 +13,14 @@
     _texts_to_nodes,
     TextNode,
 )
-from ragstack_knowledge_store.link_tag import (
+from ragstack_langchain.graph_store.links import (
+    METADATA_LINKS_KEY,
     BidirLinkTag,
     IncomingLinkTag,
     OutgoingLinkTag,
 )
 from ragstack_tests_utils.test_store import KEYSPACE
+
 from .conftest import get_local_cassandra_test_store, get_astradb_test_store
 from ragstack_langchain.graph_store import CassandraGraphStore
 
@@ -35,7 +37,7 @@ def __init__(self, session: Session, keyspace: str, embedding: Embeddings) -> No
 
     def store(
         self,
-        initial_documents: Iterable[Document] = [],
+        initial_documents: Iterable[Document] = (),
         ids: Optional[Iterable[str]] = None,
         embedding: Optional[Embeddings] = None,
     ) -> CassandraGraphStore:
@@ -123,7 +125,7 @@ def test_link_directed(cassandra: GraphStoreFactory) -> None:
         page_content="A",
         metadata={
             "content_id": "a",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 IncomingLinkTag(kind="hyperlink", tag="http://a"),
             },
         },
@@ -132,7 +134,7 @@ def test_link_directed(cassandra: GraphStoreFactory) -> None:
         page_content="B",
         metadata={
             "content_id": "b",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 IncomingLinkTag(kind="hyperlink", tag="http://b"),
                 OutgoingLinkTag(kind="hyperlink", tag="http://a"),
             },
@@ -142,7 +144,7 @@ def test_link_directed(cassandra: GraphStoreFactory) -> None:
         page_content="C",
         metadata={
             "content_id": "c",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 OutgoingLinkTag(kind="hyperlink", tag="http://a"),
             },
         },
@@ -151,7 +153,7 @@ def test_link_directed(cassandra: GraphStoreFactory) -> None:
         page_content="D",
         metadata={
             "content_id": "d",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 OutgoingLinkTag(kind="hyperlink", tag="http://a"),
                 OutgoingLinkTag(kind="hyperlink", tag="http://b"),
             },
@@ -196,7 +198,7 @@ def test_mmr_traversal(request, gs_factory: str):
         page_content="-0.124",
         metadata={
             "content_id": "v0",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 OutgoingLinkTag(kind="explicit", tag="link"),
             },
         },
@@ -211,7 +213,7 @@ def test_mmr_traversal(request, gs_factory: str):
         page_content="+0.25",
         metadata={
             "content_id": "v2",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 IncomingLinkTag(kind="explicit", tag="link"),
             },
         },
@@ -220,7 +222,7 @@ def test_mmr_traversal(request, gs_factory: str):
         page_content="+1.0",
         metadata={
             "content_id": "v3",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 IncomingLinkTag(kind="explicit", tag="link"),
             },
         },
@@ -255,7 +257,7 @@ def test_write_retrieve_keywords(request, gs_factory: str):
         page_content="Typical Greetings",
         metadata={
             "content_id": "greetings",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 IncomingLinkTag(kind="parent", tag="parent"),
             },
         },
@@ -264,7 +266,7 @@ def test_write_retrieve_keywords(request, gs_factory: str):
         page_content="Hello World",
         metadata={
             "content_id": "doc1",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 OutgoingLinkTag(kind="parent", tag="parent"),
                 BidirLinkTag(kind="kw", tag="greeting"),
                 BidirLinkTag(kind="kw", tag="world"),
@@ -275,7 +277,7 @@ def test_write_retrieve_keywords(request, gs_factory: str):
         page_content="Hello Earth",
         metadata={
             "content_id": "doc2",
-            "link_tags": {
+            METADATA_LINKS_KEY: {
                 OutgoingLinkTag(kind="parent", tag="parent"),
                 BidirLinkTag(kind="kw", tag="greeting"),
                 BidirLinkTag(kind="kw", tag="earth"),
@@ -320,6 +322,13 @@ def test_texts_to_nodes():
         TextNode(metadata={"a": "b"}, text="a"),
         TextNode(metadata={"c": "d"}, text="b"),
     ]
+    assert list(
+        _texts_to_nodes(
+            ["a"],
+            [{"links": {IncomingLinkTag(kind="hyperlink", tag="http://b")}}],
+            None,
+        )
+    ) == [TextNode(links={IncomingLinkTag(kind="hyperlink", tag="http://b")}, text="a")]
     with pytest.raises(ValueError):
         list(_texts_to_nodes(["a", "b"], None, ["a"]))
     with pytest.raises(ValueError):
@@ -332,15 +341,23 @@ def test_texts_to_nodes():
 
 def test_documents_to_nodes():
     documents = [
-        Document(page_content="a", metadata={"a": "b"}),
+        Document(
+            page_content="a",
+            metadata={"links": {IncomingLinkTag(kind="hyperlink", tag="http://b")}},
+        ),
         Document(page_content="b", metadata={"c": "d"}),
     ]
     assert list(_documents_to_nodes(documents, ["a", "b"])) == [
-        TextNode(id="a", metadata={"a": "b"}, text="a"),
+        TextNode(
+            id="a",
+            metadata={},
+            links={IncomingLinkTag(kind="hyperlink", tag="http://b")},
+            text="a",
+        ),
         TextNode(id="b", metadata={"c": "d"}, text="b"),
     ]
     assert list(_documents_to_nodes(documents, None)) == [
-        TextNode(metadata={"a": "b"}, text="a"),
+        TextNode(links={IncomingLinkTag(kind="hyperlink", tag="http://b")}, text="a"),
         TextNode(metadata={"c": "d"}, text="b"),
     ]
     with pytest.raises(ValueError):