diff --git a/lib/language_server/Diagnostics.ml b/lib/language_server/Diagnostics.ml
index d358d5c..12e0e89 100644
--- a/lib/language_server/Diagnostics.ml
+++ b/lib/language_server/Diagnostics.ml
@@ -27,53 +27,51 @@ let publish_for (forest : State.t) (lsp_uri : Lsp.Uri.t)
 let published : (string, unit) Hashtbl.t = Hashtbl.create 64
 
 let compute (document : Lsp.Text_document.t) =
-  let Lsp_state.{forest; ready; _} = Lsp_state.get () in
-  if !ready then begin
-    let lsp_uri = Lsp.Text_document.documentUri document in
-    let uri = URI.of_lsp_uri ~base:forest.config.url lsp_uri in
-    ignore (Link_checker.recheck ~forest uri);
-    (* Diagnostics are stored per URI, but we need to publish per file *)
-    let targets = ref (URI.Set.singleton uri) in
-    let record u =
-      targets := URI.Set.add (State.parent_file_uri ~forest u) !targets
+  let Lsp_state.{forest; ready = is_ready, _; _} = Lsp_state.get () in
+  Eio.Promise.await is_ready;
+  let lsp_uri = Lsp.Text_document.documentUri document in
+  let uri = URI.of_lsp_uri ~base:forest.config.url lsp_uri in
+  ignore (Link_checker.recheck ~forest uri);
+  (* Diagnostics are stored per URI, but we need to publish per file *)
+  let targets = ref (URI.Set.singleton uri) in
+  let record u =
+    targets := URI.Set.add (State.parent_file_uri ~forest u) !targets
+  in
+  State.iter_diagnostics (fun u _ -> record u) forest;
+  let dirty_owners =
+    State.with_lock forest (fun () ->
+        Duplicates.reset_dirty_owners forest.duplicates)
+  in
+  URI.Set.iter record dirty_owners;
+  let by_path : (string, Lsp.Uri.t * Error.t list) Hashtbl.t =
+    Hashtbl.create 16
+  in
+  begin
+    (* For each publishing target *)
+    let@ root = URI.Set.iter @~ !targets in
+    let@ doc = Option.iter @~ State.get_document ~forest root in
+    let root_lsp_uri = Lsp.Text_document.documentUri doc in
+    (* Gather regular and duplicate-tree diagnostics *)
+    let owned =
+      List.concat_map
+        (State.get_diagnostics ~forest)
+        (Duplicates.owned_subtrees forest.duplicates root)
     in
-    State.iter_diagnostics (fun u _ -> record u) forest;
-    let dirty_owners =
-      State.with_lock forest (fun () ->
-          Duplicates.reset_dirty_owners forest.duplicates)
-    in
-    URI.Set.iter record dirty_owners;
-    let by_path : (string, Lsp.Uri.t * Error.t list) Hashtbl.t =
-      Hashtbl.create 16
-    in
-    begin
-      (* For each publishing target *)
-      let@ root = URI.Set.iter @~ !targets in
-      let@ doc = Option.iter @~ State.get_document ~forest root in
-      let root_lsp_uri = Lsp.Text_document.documentUri doc in
-      (* Gather regular and duplicate-tree diagnostics *)
-      let owned =
-        List.concat_map
-          (State.get_diagnostics ~forest)
-          (Duplicates.owned_subtrees forest.duplicates root)
-      in
-      Hashtbl.replace by_path
-        (Lsp.Uri.to_path root_lsp_uri)
-        (root_lsp_uri, State.get_diagnostics ~forest root @ owned)
-    end;
-    (* For previously published diagnostics *)
-    published
-    |> Hashtbl.iter (fun path () ->
-        (* If they no longer have diagnostics, clear the entry *)
-        if not (Hashtbl.mem by_path path) then
-          Hashtbl.replace by_path path (Lsp.Uri.of_path path, []));
-    by_path
-    |> Hashtbl.iter (fun path (target, diagnostics) ->
-        begin match diagnostics with
-        (* and publish the empty list to clear the editors diagnostics*)
-        | [] -> Hashtbl.remove published path
-        | _ -> Hashtbl.replace published path ()
-        end;
-        publish_for forest target diagnostics)
-  end
-  else ()
+    Hashtbl.replace by_path
+      (Lsp.Uri.to_path root_lsp_uri)
+      (root_lsp_uri, State.get_diagnostics ~forest root @ owned)
+  end;
+  (* For previously published diagnostics *)
+  published
+  |> Hashtbl.iter (fun path () ->
+      (* If they no longer have diagnostics, clear the entry *)
+      if not (Hashtbl.mem by_path path) then
+        Hashtbl.replace by_path path (Lsp.Uri.of_path path, []));
+  by_path
+  |> Hashtbl.iter (fun path (target, diagnostics) ->
+      begin match diagnostics with
+      (* and publish the empty list to clear the editors diagnostics*)
+      | [] -> Hashtbl.remove published path
+      | _ -> Hashtbl.replace published path ()
+      end;
+      publish_for forest target diagnostics)
diff --git a/lib/language_server/Forester_lsp.ml b/lib/language_server/Forester_lsp.ml
index b89c9ef..b08fba1 100644
--- a/lib/language_server/Forester_lsp.ml
+++ b/lib/language_server/Forester_lsp.ml
@@ -205,7 +205,7 @@ let start ~env ~sw ~port ~serve ~(config_path : string option) =
   let config = Forester_frontend.Forester.with_docs_foreign config in
   let forest = State.make ~sw ~env ~config ~dev:true in
   let addr_completions = URI.Tbl.create 1000 in
-  let ready = ref false in
+  let (is_ready, set_ready) as ready = Eio.Promise.create () in
   Eio.Switch.run @@ fun fiber_sw ->
   if serve then begin
     let@ () = Eio.Fiber.fork_daemon ~sw:fiber_sw in
@@ -222,7 +222,7 @@ let start ~env ~sw ~port ~serve ~(config_path : string option) =
   end;
   let@ () =
     Server.run
-      ~init:{forest; lsp_io; should_shutdown = false; addr_completions; ready}
+      ~init:{forest; lsp_io; should_shutdown = false; addr_completions; ready }
   in
   begin
     initialize ();
@@ -232,6 +232,6 @@ let start ~env ~sw ~port ~serve ~(config_path : string option) =
     ignore (Link_checker.check_all ~forest);
     let fresh_completions = Completion.populate_addr_completions ~forest in
     URI.Tbl.iter (URI.Tbl.replace addr_completions) fresh_completions;
-    ready := true
+    Eio.Promise.resolve set_ready ()
   end;
   event_loop ()
diff --git a/lib/language_server/Lsp_state.ml b/lib/language_server/Lsp_state.ml
index d6ae951..2ecda5d 100644
--- a/lib/language_server/Lsp_state.ml
+++ b/lib/language_server/Lsp_state.ml
@@ -13,7 +13,7 @@ type state = {
   should_shutdown: bool;
   lsp_io: LspEio.io;
   addr_completions: Lsp.Types.CompletionItem.t URI.Tbl.t;
-  ready: bool ref;
+  ready: unit Eio.Promise.t * unit Eio.Promise.u;
 }
 
 module M = Algaeff.State.Make (struct