diff --git a/modules/services/swayidle.nix b/modules/services/swayidle.nix
index 79da15c80..66e22966c 100644
--- a/modules/services/swayidle.nix
+++ b/modules/services/swayidle.nix
@@ -1,6 +1,7 @@
 {
   config,
   lib,
+  options,
   pkgs,
   ...
 }:
@@ -99,22 +100,14 @@ in
       events = mkOption {
         type =
           with types;
-          (coercedTo (listOf attrs)) (
+          coercedTo (listOf attrs) (
             events:
-            lib.warn
-              ''
-                The syntax of services.swayidle.events has changed. While it
-                previously accepted a list of events, it now accepts an attrset
-                keyed by the event name.
-              ''
-              (
-                lib.listToAttrs (
-                  map (e: {
-                    name = e.event;
-                    value = e.command;
-                  }) events
-                )
-              )
+            lib.listToAttrs (
+              map (e: {
+                name = e.event;
+                value = e.command;
+              }) events
+            )
           ) (submodule eventsModule);
         default = { };
         example = literalExpression ''
@@ -145,6 +138,21 @@ in
     };
 
   config = lib.mkIf cfg.enable {
+    warnings = lib.optional (lib.any builtins.isList options.services.swayidle.events.definitions) (
+      lib.hm.deprecations.mkDeprecatedOptionValueWarning {
+        option = [
+          "services"
+          "swayidle"
+          "events"
+        ];
+        old = "a list";
+        replacement = "an attribute set keyed by event name";
+        details = ''
+          Use event names as attribute keys and commands as values.
+        '';
+      }
+    );
+
     assertions = [
       (lib.hm.assertions.assertPlatform "services.swayidle" pkgs lib.platforms.linux)
     ];
diff --git a/tests/modules/services/swayidle/legacy-configuration.nix b/tests/modules/services/swayidle/legacy-configuration.nix
index e07834fa7..3081cfc12 100644
--- a/tests/modules/services/swayidle/legacy-configuration.nix
+++ b/tests/modules/services/swayidle/legacy-configuration.nix
@@ -1,5 +1,12 @@
 { config, ... }:
 {
+  # Exercise merging legacy list definitions with new attrset definitions.
+  imports = [
+    {
+      services.swayidle.events.after-resume = "notify-send resumed";
+    }
+  ];
+
   services.swayidle = {
     enable = true;
     package = config.lib.test.mkStubPackage { outPath = "@swayidle@"; };
@@ -15,11 +22,13 @@
     ];
   };
 
-  test.asserts.evalWarnings.expected = [
+  test.asserts.warnings.expected = [
     ''
-      The syntax of services.swayidle.events has changed. While it
-      previously accepted a list of events, it now accepts an attrset
-      keyed by the event name.
+      Using `services.swayidle.events` as a list is deprecated and will be
+      removed in a future release. Please use an attribute set keyed by event name instead.
+
+      Use event names as attribute keys and commands as values.
+
     ''
   ];
 
@@ -36,7 +45,7 @@
 
       [Service]
       Environment=PATH=@bash-interactive@/bin
-      ExecStart=@swayidle@/bin/dummy -w before-sleep 'swaylock -fF' lock 'swaylock -fF'
+      ExecStart=@swayidle@/bin/dummy -w after-resume 'notify-send resumed' before-sleep 'swaylock -fF' lock 'swaylock -fF'
       Restart=always
       Type=simple