diff --git a/AGENTS.md b/AGENTS.md
index 1a34010f..a5b85456 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -140,9 +140,9 @@ repository, and cross-link them — no need to be told.
   change.
 - `~/codes/nix-secrets` — the private agenix store behind `secrets/` and the `mysecrets` input:
   ciphertext and recipient rules for the secrets declared here.
-- `wallpapers`, `nur-ryan4yin`, `nu_scripts`, `mattpocock-skills`, `i-have-adhd` — flake inputs from
-  the user's own repositories; bump with `just upp <input>` after their source changes, do not edit
-  them from here.
+- `wallpapers`, `nur-ryan4yin`, `pyclipsync`, `nu_scripts`, `mattpocock-skills`, `i-have-adhd` —
+  flake inputs from the user's own repositories; bump with `just upp <input>` after their source
+  changes, do not edit them from here.
 
 ## Further Context
 
diff --git a/flake.lock b/flake.lock
index f9cfcc7c..f257ff3a 100644
--- a/flake.lock
+++ b/flake.lock
@@ -851,6 +851,26 @@
         "type": "github"
       }
     },
+    "pyclipsync": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1793503810,
+        "narHash": "sha256-qh3Wjb1gV9FO01vUTGMNcWRwwQ9iUH0tkzVjObEn5J4=",
+        "owner": "ryan4yin",
+        "repo": "pyclipsync",
+        "rev": "080fbb7a21f4afe298d4eaa400645388ec000231",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ryan4yin",
+        "repo": "pyclipsync",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "agenix": "agenix",
@@ -884,6 +904,7 @@
         "ponytail": "ponytail",
         "pre-commit-hooks": "pre-commit-hooks",
         "preservation": "preservation",
+        "pyclipsync": "pyclipsync",
         "wallpapers": "wallpapers"
       }
     },
diff --git a/flake.nix b/flake.nix
index 6058e266..9be9d088 100644
--- a/flake.nix
+++ b/flake.nix
@@ -203,5 +203,11 @@
       url = "github:ryan4yin/nur-packages";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
+    # Wayland <-> X11 clipboard sync for xwayland-satellite (niri).
+    pyclipsync = {
+      url = "github:ryan4yin/pyclipsync";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 }
diff --git a/home/linux/gui/niri/default.nix b/home/linux/gui/niri/default.nix
index 422b6050..399d58ea 100644
--- a/home/linux/gui/niri/default.nix
+++ b/home/linux/gui/niri/default.nix
@@ -2,12 +2,18 @@
   pkgs,
   config,
   lib,
+  pyclipsync,
   ...
 }@args:
 let
   cfg = config.modules.desktop.niri;
 in
 {
+  imports = [
+    # provides `services.pyclipsync.enable`
+    pyclipsync.homeModules.default
+  ];
+
   options.modules.desktop.niri = {
     enable = lib.mkEnableOption "niri compositor";
   };
@@ -51,6 +57,10 @@ in
           };
         };
 
+        # QQ draws a Wayland window but copies through the X11 CLIPBOARD, which
+        # xwayland-satellite bridges only while an X11 window has focus.
+        services.pyclipsync.enable = true;
+
         # NOTE: this executable is used by greetd to start a wayland session when system boot up
         # with such a vendor-no-locking script, we can switch to another wayland compositor without modifying greetd's config in NixOS module
         home.file.".wayland-session" = {