diff --git a/.github/workflows/devshell.yaml b/.github/workflows/devshell.yaml
new file mode 100644
index 0000000..6e1c80b
--- /dev/null
+++ b/.github/workflows/devshell.yaml
@@ -0,0 +1,50 @@
+name: Dev Shell
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'templates/**'
+      - '.github/workflows/devshell.yaml'
+  pull_request:
+    branches: [main]
+    paths:
+      - 'templates/**'
+      - '.github/workflows/devshell.yaml'
+
+jobs:
+  discover:
+    name: Discover templates
+    runs-on: ubuntu-24.04
+    outputs:
+      templates: ${{ steps.list.outputs.templates }}
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+
+      - name: List templates
+        id: list
+        run: |
+          templates=$(ls -1 templates/ | jq -Rc '[.,inputs]')
+          echo "templates=$templates" >> "$GITHUB_OUTPUT"
+
+  devshell-build:
+    name: Build devShell (${{ matrix.template }})
+    needs: discover
+    runs-on: ubuntu-24.04
+    strategy:
+      fail-fast: false
+      matrix:
+        template: ${{ fromJson(needs.discover.outputs.templates) }}
+
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+
+      - uses: cachix/install-nix-action@616559265b40713947b9c190a8ff4b507b5df49b # v31
+
+      - uses: cachix/cachix-action@1eb2ef646ac0255473d23a5907ad7b04ce94065c # v17
+        with:
+          name: rito528-dotfiles
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - name: Build devShell
+        run: nix build ./templates/${{ matrix.template }}#devShells.x86_64-linux.default
diff --git a/README.md b/README.md
index 0cd83fc..fda921b 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ dotfiles/
 │   ├── lint.yaml             # shellcheck・nixfmt Lint
 │   ├── integration-test.yaml # Cachix を使った home-manager ビルド検証
 │   ├── nix.yaml              # Nix flake check
+│   ├── devshell.yaml         # templates/ 配下の devShell ビルド検証
 │   ├── nix-update-pr.yaml    # Renovate 時のハッシュ自動更新
 │   ├── update-flake-lock.yaml # 週次 flake.lock 更新
 │   ├── e2e-setup-test.yaml   # セットアップ E2E テスト
@@ -137,32 +138,13 @@ home-manager generations
 
 ## 開発環境テンプレート
 
-プロジェクトごとに独立した Nix 開発環境を提供するテンプレートを管理しています。
-
-- `rust`
-- `scala`
-- `typescript`
+プロジェクトごとに独立した Nix 開発環境を提供するテンプレートを管理しています（`templates/` 参照）。
 
 ### 自分のプロジェクトで使う場合
 
 ```bash
-# プロジェクトディレクトリで初期化
-nix flake init -t github:rito528/dotfiles#rust
-nix flake init -t github:rito528/dotfiles#scala
-nix flake init -t github:rito528/dotfiles#typescript
-```
-
-### OSS プロジェクト等で dotfiles の devShell を直接参照する場合
-
-```bash
-# Rust 環境に入る
-nix develop 'github:rito528/dotfiles#rust'
-
-# Scala 環境に入る
-nix develop 'github:rito528/dotfiles#scala'
-
-# TypeScript 環境に入る
-nix develop 'github:rito528/dotfiles#typescript'
+# プロジェクトディレクトリで初期化（例）
+nix flake init -t github:rito528/dotfiles#seichi-infra
 ```
 
 ### direnv との連携
@@ -170,8 +152,13 @@ nix develop 'github:rito528/dotfiles#typescript'
 プロジェクトディレクトリに `.envrc` を作成することで、ディレクトリに入ると自動的に開発環境が有効になります：
 
 ```bash
+# テンプレートで初期化したプロジェクトの場合
 echo "use flake" > .envrc
 direnv allow
+
+# dotfiles のテンプレートを直接参照する場合
+echo "use flake 'github:rito528/dotfiles?dir=templates/rust'" > .envrc
+direnv allow
 ```
 
 > `.envrc` はプロジェクト固有の設定のため、global gitignore に追加することを推奨します。
diff --git a/flake.nix b/flake.nix
index 8b742fa..036507a 100644
--- a/flake.nix
+++ b/flake.nix
@@ -7,17 +7,12 @@
       url = "github:nix-community/home-manager";
       inputs.nixpkgs.follows = "nixpkgs";
     };
-    rust-overlay = {
-      url = "github:oxalica/rust-overlay";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
   };
 
   outputs =
     {
       nixpkgs,
       home-manager,
-      rust-overlay,
       ...
     }:
     let
@@ -31,10 +26,6 @@
             "github-copilot-cli"
           ];
       };
-      pkgsWithRust = import nixpkgs {
-        inherit system;
-        overlays = [ rust-overlay.overlays.default ];
-      };
       mkHomeConfig =
         username: homeDirectory: personal:
         home-manager.lib.homeManagerConfiguration {
@@ -62,7 +53,6 @@
         );
       npmPackages = loadPackagesDir ./modules/npm/packages;
       extraPackages = loadPackagesDir ./modules/packages;
-      mkShellWithZsh = mkPkgs: args: mkPkgs.mkShell ({ SHELL = "${pkgs.zsh}/bin/zsh"; } // args);
     in
     {
       packages.${system} = npmPackages // extraPackages;
@@ -79,18 +69,6 @@
         };
       };
       templates = {
-        rust = {
-          path = ./templates/rust;
-          description = "Rust development environment";
-        };
-        scala = {
-          path = ./templates/scala;
-          description = "Scala development environment";
-        };
-        typescript = {
-          path = ./templates/typescript;
-          description = "TypeScript (pnpm) development environment";
-        };
         seichi-assist = {
           path = ./templates/seichi-assist;
           description = "SeichiAssist development environment";
@@ -108,70 +86,5 @@
           description = "seichi-portal-frontend development environment";
         };
       };
-      devShells.${system} = {
-        rust = mkShellWithZsh pkgsWithRust {
-          buildInputs = [
-            pkgsWithRust.rust-bin.stable.latest.default
-            pkgsWithRust.pkg-config
-            pkgsWithRust.openssl
-          ];
-        };
-        scala = mkShellWithZsh pkgs {
-          buildInputs = [
-            pkgs.jdk17
-            pkgs.sbt
-            pkgs.metals
-            pkgs.scalafmt
-            pkgs.stdenv.cc.cc.lib
-          ];
-          shellHook = ''
-            export LD_LIBRARY_PATH="${pkgs.stdenv.cc.cc.lib}/lib''${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
-          '';
-        };
-        typescript = mkShellWithZsh pkgs {
-          buildInputs = [
-            pkgs.nodejs_22
-            pkgs.pnpm
-            pkgs.typescript
-            pkgs.typescript-language-server
-            pkgs.vscode-langservers-extracted
-          ];
-        };
-        seichi-assist = mkShellWithZsh pkgs {
-          buildInputs = [
-            pkgs.jdk17
-            pkgs.sbt
-            pkgs.metals
-            pkgs.scalafmt
-            pkgs.stdenv.cc.cc.lib
-          ];
-          shellHook = ''
-            export LD_LIBRARY_PATH="${pkgs.stdenv.cc.cc.lib}/lib''${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
-          '';
-        };
-        seichi-infra = mkShellWithZsh pkgs {
-          buildInputs = [
-            pkgs.terraform
-            pkgs.tflint
-            pkgs.kubectl
-            pkgs.kubernetes-helm
-          ];
-        };
-        seichi-portal-backend = mkShellWithZsh pkgsWithRust {
-          buildInputs = [
-            pkgsWithRust.rust-bin.stable.latest.default
-            pkgsWithRust.pkg-config
-            pkgsWithRust.openssl
-            pkgsWithRust.cargo-make
-            pkgsWithRust.sqlx-cli
-          ];
-        };
-        seichi-portal-frontend = mkShellWithZsh pkgs {
-          buildInputs = [
-            pkgs.nodejs_22
-            pkgs.pnpm
-          ];
-        };
-      };
     };
 }
diff --git a/templates/rust/.envrc b/templates/rust/.envrc
deleted file mode 100644
index 3550a30..0000000
--- a/templates/rust/.envrc
+++ /dev/null
@@ -1 +0,0 @@
-use flake
diff --git a/templates/rust/flake.nix b/templates/rust/flake.nix
deleted file mode 100644
index 30367eb..0000000
--- a/templates/rust/flake.nix
+++ /dev/null
@@ -1,30 +0,0 @@
-{
-  description = "Rust development environment";
-
-  inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    rust-overlay = {
-      url = "github:oxalica/rust-overlay";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
-  };
-
-  outputs =
-    { nixpkgs, rust-overlay, ... }:
-    let
-      system = "x86_64-linux";
-      pkgs = import nixpkgs {
-        inherit system;
-        overlays = [ rust-overlay.overlays.default ];
-      };
-    in
-    {
-      devShells.${system}.default = pkgs.mkShell {
-        buildInputs = [
-          pkgs.rust-bin.stable.latest.default
-          pkgs.pkg-config
-          pkgs.openssl
-        ];
-      };
-    };
-}
diff --git a/templates/scala/.envrc b/templates/scala/.envrc
deleted file mode 100644
index 3550a30..0000000
--- a/templates/scala/.envrc
+++ /dev/null
@@ -1 +0,0 @@
-use flake
diff --git a/templates/scala/flake.nix b/templates/scala/flake.nix
deleted file mode 100644
index c80b3cc..0000000
--- a/templates/scala/flake.nix
+++ /dev/null
@@ -1,23 +0,0 @@
-{
-  description = "Scala development environment";
-
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-
-  outputs =
-    { nixpkgs, ... }:
-    let
-      system = "x86_64-linux";
-      pkgs = import nixpkgs { inherit system; };
-    in
-    {
-      devShells.${system}.default = pkgs.mkShell {
-        buildInputs = [
-          pkgs.jdk17
-          pkgs.sbt
-          pkgs.bloop
-          pkgs.metals
-          pkgs.scalafmt
-        ];
-      };
-    };
-}
diff --git a/templates/seichi-infra/flake.nix b/templates/seichi-infra/flake.nix
index 61138a9..dfebda4 100644
--- a/templates/seichi-infra/flake.nix
+++ b/templates/seichi-infra/flake.nix
@@ -7,7 +7,10 @@
     { nixpkgs, ... }:
     let
       system = "x86_64-linux";
-      pkgs = import nixpkgs { inherit system; };
+      pkgs = import nixpkgs {
+        inherit system;
+        config.allowUnfreePredicate = pkg: builtins.elem (nixpkgs.lib.getName pkg) [ "terraform" ];
+      };
     in
     {
       devShells.${system}.default = pkgs.mkShell {
diff --git a/templates/typescript/.envrc b/templates/typescript/.envrc
deleted file mode 100644
index 3550a30..0000000
--- a/templates/typescript/.envrc
+++ /dev/null
@@ -1 +0,0 @@
-use flake
diff --git a/templates/typescript/flake.nix b/templates/typescript/flake.nix
deleted file mode 100644
index b4fe311..0000000
--- a/templates/typescript/flake.nix
+++ /dev/null
@@ -1,23 +0,0 @@
-{
-  description = "TypeScript (pnpm) development environment";
-
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-
-  outputs =
-    { nixpkgs, ... }:
-    let
-      system = "x86_64-linux";
-      pkgs = import nixpkgs { inherit system; };
-    in
-    {
-      devShells.${system}.default = pkgs.mkShell {
-        buildInputs = [
-          pkgs.nodejs_24
-          pkgs.pnpm
-          pkgs.typescript
-          pkgs.typescript-language-server
-          pkgs.vscode-langservers-extracted
-        ];
-      };
-    };
-}