diff --git a/pkgs/by-name/ag/ags_1/package.nix b/pkgs/by-name/ag/ags_1/package.nix
index 49f658236ca1..8a652890c3b3 100644
--- a/pkgs/by-name/ag/ags_1/package.nix
+++ b/pkgs/by-name/ag/ags_1/package.nix
@@ -59,6 +59,11 @@ buildNpmPackage (finalAttrs: {
     upower
   ];
 
+  patches = [
+    # Workaround for TypeScript 5.9: https://github.com/Aylur/ags/issues/725#issuecomment-3070009695
+    ./ts59.patch
+  ];
+
   postPatch = ''
     chmod u+x ./post_install.sh && patchShebangs ./post_install.sh
   '';
diff --git a/pkgs/by-name/ag/ags_1/ts59.patch b/pkgs/by-name/ag/ags_1/ts59.patch
new file mode 100644
index 000000000000..5f3f9bb29f33
--- /dev/null
+++ b/pkgs/by-name/ag/ags_1/ts59.patch
@@ -0,0 +1,19 @@
+diff --git a/src/service/greetd.ts b/src/service/greetd.ts
+index 10a475e..621a427 100644
+--- a/src/service/greetd.ts
++++ b/src/service/greetd.ts
+@@ -101,8 +101,12 @@ export class Greetd extends Service {
+             ostream.put_int32(json.length, null);
+             ostream.put_string(json, null);
+ 
+-            const data = await istream.read_bytes_async(4, GLib.PRIORITY_DEFAULT, null);
+-            const length = new Uint32Array(data.get_data()?.buffer || [0])[0];
++            const data = (
++                await istream.read_bytes_async(4, GLib.PRIORITY_DEFAULT, null)
++            ).get_data();
++            const length = data
++                ? new DataView(data.buffer, data.byteOffset, data.byteLength).getUint32(0, true)
++                : 0;
+             const res = await istream.read_bytes_async(length, GLib.PRIORITY_DEFAULT, null);
+             return JSON.parse(this._decoder.decode(res.get_data()!)) as Response;
+         } finally {