feat: add gemini and codex config

modules/features/ai.nix

@@ -0,0 +1,64 @@
+{ inputs, ... }:
+let
+  sharedContext = ''
+    # AI Global Context
+
+    This shared Codex and Gemini context is intentionally minimal for now.
+
+    TODO: add persistent global AI instructions.
+  '';
+in
+{
+  flake.modules.nixos.ai = {
+    nixpkgs.overlays = [ inputs.llm-agents.overlays.default ];
+
+    nix.settings = {
+      extra-substituters = [ "https://cache.numtide.com" ];
+      extra-trusted-public-keys = [
+        "niks3.numtide.com-1:DTx8wZduET09hRmMtKdQDxNNthLQETkc/yaX7M4qK0g="
+      ];
+    };
+  };
+
+  flake.modules.homeManager.ai =
+    { config, pkgs, ... }:
+    {
+      home.sessionVariables.GEMINI_CONFIG_DIR = "${config.xdg.configHome}/gemini";
+
+      programs.gemini-cli = {
+        enable = true;
+        package = pkgs.llm-agents.gemini-cli;
+        context.AGENTS = sharedContext;
+        settings = {
+          context = {
+            fileName = [
+              "AGENTS.md"
+              "GEMINI.md"
+            ];
+            loadMemoryFromIncludeDirectories = true;
+          };
+          model.name = "gemini-3.1-pro-preview";
+        };
+      };
+
+      programs.codex = {
+        enable = true;
+        package = pkgs.llm-agents.codex;
+        context = sharedContext;
+        settings = {
+          model = "gpt-5.4";
+          model_reasoning_effort = "high";
+          plan_mode_reasoning_effort = "high";
+          tui.status_line = [
+            "model-with-reasoning"
+            "current-dir"
+            "git-branch"
+            "context-remaining"
+            "five-hour-limit"
+          ];
+          personality = "pragmatic";
+          features.undo = true;
+        };
+      };
+    };
+}

modules/features/cli-base.nix

@@ -11,7 +11,7 @@ in
       homeModules.git
       homeModules.dev-tools
       homeModules.podman
-      homeModules.gemini
+      homeModules.ai
     ];
   };
 }

modules/features/gemini.nix

@@ -1,11 +0,0 @@
-{
-  flake.modules.homeManager.gemini =
-    { config, ... }:
-    {
-      home.sessionVariables.GEMINI_CONFIG_DIR = "${config.xdg.configHome}/gemini";
-
-      programs.gemini-cli.enable = true;
-      programs.opencode.enable = true;
-      programs.npm.enable = true;
-    };
-}

modules/features/host-base.nix

@@ -12,6 +12,7 @@ in
     imports = [
       nixosModules.meta
       inputs.home-manager.nixosModules.home-manager
+      nixosModules.ai
       nixosModules.nix
       nixosModules.region-nl
     ];