diff --git a/modules/programs/zed-editor.nix b/modules/programs/zed-editor.nix
index 472fc1698..a9bd28e5e 100644
--- a/modules/programs/zed-editor.nix
+++ b/modules/programs/zed-editor.nix
@@ -14,6 +14,16 @@ let
 
   cfg = config.programs.zed-editor;
   jsonFormat = pkgs.formats.json { };
+  impureConfigMerger = empty: jqOperation: path: staticSettings: ''
+    mkdir -p $(dirname ${lib.escapeShellArg path})
+    if [ ! -e ${lib.escapeShellArg path} ]; then
+      # No file? Create it
+      echo ${lib.escapeShellArg empty} > ${lib.escapeShellArg path}
+    fi
+    config="$(${pkgs.jq}/bin/jq -s ${lib.escapeShellArg jqOperation} ${lib.escapeShellArg path} ${lib.escapeShellArg staticSettings})"
+    printf '%s\n' "$config" > ${lib.escapeShellArg path}
+    unset config
+  '';
 
   mergedSettings =
     cfg.userSettings
@@ -155,34 +165,31 @@ in
       }
     );
 
-    xdg.configFile =
-      lib.attrsets.unionOfDisjoint
-        {
-          "zed/settings.json" = (
-            mkIf (mergedSettings != { }) {
-              source = jsonFormat.generate "zed-user-settings" mergedSettings;
-            }
-          );
+    home.activation = {
+      zedSettingsActivation = lib.hm.dag.entryAfter [ "linkGeneration" ] (
+        impureConfigMerger "{}" ".[0] * .[1]" "${config.xdg.configHome}/zed/settings.json" (
+          jsonFormat.generate "zed-user-settings" mergedSettings
+        )
+      );
+      zedKeymapActivation = lib.hm.dag.entryAfter [ "linkGeneration" ] (
+        impureConfigMerger "[]"
+          ".[0] + .[1] | group_by(.context) | map(reduce .[] as $item ({}; . * $item))"
+          "${config.xdg.configHome}/zed/keymap.json"
+          (jsonFormat.generate "zed-user-keymaps" cfg.userKeymaps)
+      );
+    };
 
-          "zed/keymap.json" = (
-            mkIf (cfg.userKeymaps != { }) {
-              source = jsonFormat.generate "zed-user-keymaps" cfg.userKeymaps;
-            }
-          );
-        }
-        (
-          lib.mapAttrs' (
-            n: v:
-            lib.nameValuePair "zed/themes/${n}.json" {
-              source =
-                if lib.isString v then
-                  pkgs.writeText "zed-theme-${n}" v
-                else if builtins.isPath v || lib.isStorePath v then
-                  v
-                else
-                  jsonFormat.generate "zed-theme-${n}" v;
-            }
-          ) cfg.themes
-        );
+    xdg.configFile = lib.mapAttrs' (
+      n: v:
+      lib.nameValuePair "zed/themes/${n}.json" {
+        source =
+          if lib.isString v then
+            pkgs.writeText "zed-theme-${n}" v
+          else if builtins.isPath v || lib.isStorePath v then
+            v
+          else
+            jsonFormat.generate "zed-theme-${n}" v;
+      }
+    ) cfg.themes;
   };
 }
diff --git a/tests/modules/programs/zed-editor/extensions.nix b/tests/modules/programs/zed-editor/extensions.nix
index e3d868725..0cb20a9a0 100644
--- a/tests/modules/programs/zed-editor/extensions.nix
+++ b/tests/modules/programs/zed-editor/extensions.nix
@@ -1,4 +1,9 @@
-{ config, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 
 {
   programs.zed-editor = {
@@ -11,20 +16,54 @@
     ];
   };
 
+  home.homeDirectory = lib.mkForce "/@TMPDIR@/hm-user";
+
   nmt.script =
     let
+      preexistingSettings = builtins.toFile "preexisting.json" ''
+        {
+          "auto_install_extensions": {
+            "python": true,
+            "javascript": true
+          }
+        }
+      '';
+
       expectedContent = builtins.toFile "expected.json" ''
         {
           "auto_install_extensions": {
+            "python": true,
+            "javascript": true,
             "html": true,
             "swift": true,
             "xy-zed": true
           }
         }
       '';
+
+      settingsPath = ".config/zed/settings.json";
+
+      activationScript = pkgs.writeScript "activation" config.home.activation.zedSettingsActivation.data;
     in
     ''
-      assertFileExists "home-files/.config/zed/settings.json"
-      assertFileContent "home-files/.config/zed/settings.json" "${expectedContent}"
+      export HOME=$TMPDIR/hm-user
+
+      # Simulate preexisting settings
+      mkdir -p $HOME/.config/zed
+      cat ${preexistingSettings} > $HOME/${settingsPath}
+
+      # Run the activation script
+      substitute ${activationScript} $TMPDIR/activate --subst-var TMPDIR
+      chmod +x $TMPDIR/activate
+      $TMPDIR/activate
+
+      # Validate the merged settings
+      assertFileExists "$HOME/${settingsPath}"
+      assertFileContent "$HOME/${settingsPath}" "${expectedContent}"
+
+      # Test idempotency
+      $TMPDIR/activate
+      assertFileExists "$HOME/${settingsPath}"
+      assertFileContent "$HOME/${settingsPath}" "${expectedContent}"
     '';
 }
diff --git a/tests/modules/programs/zed-editor/keymap.nix b/tests/modules/programs/zed-editor/keymap.nix
index ca70647a1..03a3a3fcd 100644
--- a/tests/modules/programs/zed-editor/keymap.nix
+++ b/tests/modules/programs/zed-editor/keymap.nix
@@ -1,5 +1,9 @@
-# Test custom keymap functionality
-{ config, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 
 {
   programs.zed-editor = {
@@ -20,28 +24,78 @@
     ];
   };
 
+  home.homeDirectory = lib.mkForce "/@TMPDIR@/hm-user";
+
   nmt.script =
     let
-      expectedContent = builtins.toFile "expected.json" ''
+      preexistingKeymaps = builtins.toFile "preexisting.json" ''
         [
           {
             "bindings": {
-              "up": "menu::SelectPrev"
+              "down": "menu::SelectNext"
             }
           },
           {
             "bindings": {
-              "escape": "editor::Cancel"
+              "down": "select"
+            },
+            "context": "Terminal"
+          },
+          {
+            "bindings": {
+              "enter": "newline"
             },
             "context": "Editor"
           }
         ]
       '';
 
+      expectedContent = builtins.toFile "expected.json" ''
+        [
+          {
+            "bindings": {
+              "down": "menu::SelectNext",
+              "up": "menu::SelectPrev"
+            }
+          },
+          {
+            "bindings": {
+              "enter": "newline",
+              "escape": "editor::Cancel"
+            },
+            "context": "Editor"
+          },
+          {
+            "bindings": {
+              "down": "select"
+            },
+            "context": "Terminal"
+          }
+        ]
+      '';
+
       keymapPath = ".config/zed/keymap.json";
+      activationScript = pkgs.writeScript "activation" config.home.activation.zedKeymapActivation.data;
     in
     ''
-      assertFileExists "home-files/${keymapPath}"
-      assertFileContent "home-files/${keymapPath}" "${expectedContent}"
+      export HOME=$TMPDIR/hm-user
+
+      # Simulate preexisting keymaps
+      mkdir -p $HOME/.config/zed
+      cat ${preexistingKeymaps} > $HOME/${keymapPath}
+
+      # Run the activation script
+      substitute ${activationScript} $TMPDIR/activate --subst-var TMPDIR
+      chmod +x $TMPDIR/activate
+      $TMPDIR/activate
+
+      # Validate the merged keymaps
+      assertFileExists "$HOME/${keymapPath}"
+      assertFileContent "$HOME/${keymapPath}" "${expectedContent}"
+
+      # Test idempotency
+      $TMPDIR/activate
+      assertFileExists "$HOME/${keymapPath}"
+      assertFileContent "$HOME/${keymapPath}" "${expectedContent}"
     '';
 }
diff --git a/tests/modules/programs/zed-editor/settings.nix b/tests/modules/programs/zed-editor/settings.nix
index 258d4ceac..2e95507ee 100644
--- a/tests/modules/programs/zed-editor/settings.nix
+++ b/tests/modules/programs/zed-editor/settings.nix
@@ -1,5 +1,10 @@
 # Test custom keymap functionality
-{ config, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 
 {
   programs.zed-editor = {
@@ -16,24 +21,56 @@
     };
   };
 
+  home.homeDirectory = lib.mkForce "/@TMPDIR@/hm-user";
+
   nmt.script =
     let
+      preexistingSettings = builtins.toFile "preexisting.json" ''
+        {
+          "theme": "Default",
+          "features": {
+            "copilot": true,
+            "ai_assist": true
+          },
+          "vim_mode": true
+        }
+      '';
+
       expectedContent = builtins.toFile "expected.json" ''
         {
-          "buffer_font_size": 16,
-          "features": {
-            "copilot": false
-          },
           "theme": "XY-Zed",
-          "ui_font_size": 16,
-          "vim_mode": false
+          "features": {
+            "copilot": false,
+            "ai_assist": true
+          },
+          "vim_mode": false,
+          "buffer_font_size": 16,
+          "ui_font_size": 16
         }
       '';
 
       settingsPath = ".config/zed/settings.json";
+      activationScript = pkgs.writeScript "activation" config.home.activation.zedSettingsActivation.data;
     in
     ''
-      assertFileExists "home-files/${settingsPath}"
-      assertFileContent "home-files/${settingsPath}" "${expectedContent}"
+      export HOME=$TMPDIR/hm-user
+
+      # Simulate preexisting settings
+      mkdir -p $HOME/.config/zed
+      cat ${preexistingSettings} > $HOME/${settingsPath}
+
+      # Run the activation script
+      substitute ${activationScript} $TMPDIR/activate --subst-var TMPDIR
+      chmod +x $TMPDIR/activate
+      $TMPDIR/activate
+
+      # Validate the merged settings
+      assertFileExists "$HOME/${settingsPath}"
+      assertFileContent "$HOME/${settingsPath}" "${expectedContent}"
+
+      # Test idempotency
+      $TMPDIR/activate
+      assertFileExists "$HOME/${settingsPath}"
+      assertFileContent "$HOME/${settingsPath}" "${expectedContent}"
     '';
 }