diff --git a/home-manager/programs/gh/common.nix b/home-manager/programs/gh/common.nix
new file mode 100644
index 00000000..39776534
--- /dev/null
+++ b/home-manager/programs/gh/common.nix
@@ -0,0 +1,22 @@
+# 全ホスト共通の gh 設定。
+# oberon は nixpkgs-stable (nixos-25.11) を使うため、ここには stable にも
+# 存在するものだけを置く。unstable 限定の拡張は default.nix 側で足す。
+{ pkgs, ... }:
+{
+  programs.gh-prism.enable = true;
+
+  programs.gh = {
+    enable = true;
+    extensions = [
+      pkgs.gh-dash
+      pkgs.gh-poi
+    ];
+    settings = {
+      git_protocol = "ssh";
+      prompt = "enabled";
+      aliases = {
+        co = ''!id="$(gh pr list -L100 | fzf | cut -f1)"; [ -n "$id" ] && gh pr checkout "$id"'';
+      };
+    };
+  };
+}
diff --git a/home-manager/programs/gh/default.nix b/home-manager/programs/gh/default.nix
index 41a70b68..fc0db472 100644
--- a/home-manager/programs/gh/default.nix
+++ b/home-manager/programs/gh/default.nix
@@ -1,24 +1,18 @@
+# darwin (nixpkgs unstable) 用の gh 設定。
 { pkgs, sources, ... }:
 let
   gh-pr-graph = import ./gh-pr-graph.nix { inherit pkgs sources; };
 in
 {
-  programs.gh-prism.enable = true;
+  imports = [ ./common.nix ];
 
-  programs.gh = {
-    enable = true;
-    extensions = [
-      pkgs.gh-dash
-      pkgs.gh-poi
-      pkgs.gh-stack
-      gh-pr-graph
-    ];
-    settings = {
-      git_protocol = "ssh";
-      prompt = "enabled";
-      aliases = {
-        co = ''!id="$(gh pr list -L100 | fzf | cut -f1)"; [ -n "$id" ] && gh pr checkout "$id"'';
-      };
-    };
-  };
+  # ここに置く拡張が oberon に載らないのは意図的:
+  # - gh-stack は nixpkgs unstable にしか無い (nixos-25.11 には未収録)。
+  # - gh-pr-graph はローカルサーバを立ててブラウザを開くツールなので、
+  #   ヘッドレスな oberon では使えない。
+  # programs.gh.extensions は list なので common.nix の定義とマージされる。
+  programs.gh.extensions = [
+    pkgs.gh-stack
+    gh-pr-graph
+  ];
 }
diff --git a/home-manager/programs/gh/server.nix b/home-manager/programs/gh/server.nix
new file mode 100644
index 00000000..fa2681a9
--- /dev/null
+++ b/home-manager/programs/gh/server.nix
@@ -0,0 +1,5 @@
+# oberon (サーバー) 用の gh 設定。common.nix だけで完結する。
+{ ... }:
+{
+  imports = [ ./common.nix ];
+}
diff --git a/hosts/oberon/home.nix b/hosts/oberon/home.nix
index 9ca9ac07..97de2b4c 100644
--- a/hosts/oberon/home.nix
+++ b/hosts/oberon/home.nix
@@ -21,7 +21,7 @@ in
     ../../home-manager/programs/direnv
     ../../home-manager/programs/fish/server.nix
     ../../home-manager/programs/fzf
-    ../../home-manager/programs/gh
+    ../../home-manager/programs/gh/server.nix
     ../../home-manager/programs/git/server.nix
     ../../home-manager/programs/htop
     ../../home-manager/programs/hunk