diff --git a/AyCode.Blazor.Components/docs/MGGRID/MGGRID_TODO.md b/AyCode.Blazor.Components/docs/MGGRID/MGGRID_TODO.md
index f6bb8fe..f299d49 100644
--- a/AyCode.Blazor.Components/docs/MGGRID/MGGRID_TODO.md
+++ b/AyCode.Blazor.Components/docs/MGGRID/MGGRID_TODO.md
@@ -2,6 +2,8 @@
 
 For known issues / bugs see `MGGRID_ISSUES.md`.
 
+> **Server-side grid filtering — design in ADR 0004.** MgGrid `FilterMode` (Local/Server), the criteria-string forwarding, and the `DxTagBox` quick-filter template extension are captured in `AyCode.Core/docs/adr/0004-signalr-datasource-server-side-filtering.md` (in AyCode.Core repo, Status: Proposed). Not yet broken into per-step entries — reference the ADR when implementation begins.
+
 ## Priority legend
 - **P0** blocker · **P1** important · **P2** nice-to-have · **P3** idea