diff --git a/doc/changes/added/12922.md b/doc/changes/added/12922.md
new file mode 100644
index 00000000000..d9da313bdaf
--- /dev/null
+++ b/doc/changes/added/12922.md
@@ -0,0 +1 @@
+- Add the workspace root to the config trace event (#12922, @rgrinberg)
diff --git a/src/dune_trace/dune_trace.ml b/src/dune_trace/dune_trace.ml
index 43f4ef219e2..cbf3347b550 100644
--- a/src/dune_trace/dune_trace.ml
+++ b/src/dune_trace/dune_trace.ml
@@ -140,6 +140,7 @@ module Event = struct
         [ "build_dir", `String (Path.Build.to_string Path.Build.root)
         ; "argv", `List (Array.to_list Sys.argv |> List.map ~f:Json.string)
         ; "env", `List (Unix.environment () |> Array.to_list |> List.map ~f:Json.string)
+        ; "root", `String Path.(to_absolute_filename root)
         ]
       in
       match version with