diff --git a/backend/deps.edn b/backend/deps.edn
index fd5fc81398..1a3e09758d 100644
--- a/backend/deps.edn
+++ b/backend/deps.edn
@@ -69,7 +69,11 @@
 
   com.ladybugdb/lbug {:mvn/version "0.20.4"}
   ;; Required by Arrow RootAllocator (lbug only pulls arrow-memory-core).
-  org.apache.arrow/arrow-memory-netty {:mvn/version "19.0.0"}}
+  org.apache.arrow/arrow-memory-netty {:mvn/version "19.0.0"}
+
+  ;; graph-overlay: datascript index over the document, replacing the Cypher
+  ;; projection for per-file queries. See docs.local/graph roadmap.
+  datascript/datascript {:mvn/version "1.8.1"}}
 
  :paths ["src" "resources" "target/classes"]
  :aliases
diff --git a/frontend/deps.edn b/frontend/deps.edn
index b1293a652c..b63c95a2f1 100644
--- a/frontend/deps.edn
+++ b/frontend/deps.edn
@@ -9,6 +9,9 @@
   metosin/reitit-core {:mvn/version "0.11.0"}
   funcool/okulary {:mvn/version "2022.04.11-16"}
 
+  ;; graph-overlay: datascript index in the derived-index worker.
+  datascript/datascript {:mvn/version "1.8.1"}
+
   funcool/tubax
   {:git/tag "v2025.11.28"
    :git/sha "2d9a986"