diff --git a/README.md b/README.md
index c920b07..d266933 100644
--- a/README.md
+++ b/README.md
@@ -54,8 +54,8 @@ Authors:
 
 # What Is This?
 
-This is a repository template giving you a top-level structure with the
-following features.
+This repo renders **repository templates** for different languages giving you a
+top-level structure with the following features.
 
 - **Git & Git Large File System (LFS)** configured.
 - **Nix development shell** enabled with [`direnv`](https://direnv.net) and
@@ -72,6 +72,8 @@ following features.
 
 # Usage
 
+To render a new repository for language `<language>` you can use
+
 ## Over Container
 
 ```bash
@@ -92,7 +94,7 @@ See [arguments explanations here](#arguments).
 
 ## By Cloning
 
-Clone this repository to some place of your choice.
+You can also clone this repository to some place of your choice.
 
 Apply the templates with `copier` using the following:
 
@@ -181,7 +183,7 @@ The following describes the content of the top-level directories:
 
 [Source](src/go/tools/nix/shells/toolchain-go.nix)
 
-- Compiler: `go` at `1.23.X`
+- Compiler: `go` at `1.24.X`
 - Build-Tool: `go`
 - LSP: `gopls`
 - Formatter: `gofmt`, `goimports`, `golines`
@@ -195,7 +197,7 @@ The following describes the content of the top-level directories:
 - [Source](src/python/tools/nix/shells/toolchain-python.nix)
 - [Demo Rendering](https://github.com/sdsc-ordes/repository-template-python)
 
-- Interpreter: `python` at `3.12`
+- Interpreter: `python` at `3.13`
 - Build-Tool: `uv`
 - LSP: `pyright`
 - Formatter: `ruff`
diff --git a/src/generic/tools/ci/general.sh b/src/generic/tools/ci/general.sh
index 478e489..e3e9948 100644
--- a/src/generic/tools/ci/general.sh
+++ b/src/generic/tools/ci/general.sh
@@ -66,10 +66,6 @@ function ci::setup_python_venv() {
     local root_dir
     root_dir=$(git rev-parse --show-toplevel)
 
-    # If VIRTUAL_ENV is set use it.
-    export VIRTUAL_ENV="${VIRTUAL_ENV:-$root_dir/.venv}"
-    export UV_PROJECT_ENVIRONMENT="$VIRTUAL_ENV"
-
     ci::print_info "Python virtual env. dir '$UV_PROJECT_ENVIRONMENT' set."
 
     if [ ! -d "$UV_PROJECT_ENVIRONMENT" ]; then
diff --git a/src/generic/tools/nix/flake.lock b/src/generic/tools/nix/flake.lock
index a95f183..93f9f10 100644
--- a/src/generic/tools/nix/flake.lock
+++ b/src/generic/tools/nix/flake.lock
@@ -6,7 +6,8 @@
           "devenv"
         ],
         "flake-compat": [
-          "devenv"
+          "devenv",
+          "flake-compat"
         ],
         "git-hooks": [
           "devenv",
@@ -18,11 +19,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1752264895,
-        "narHash": "sha256-1zBPE/PNAkPNUsOWFET4J0cjlvziH8DOekesDmjND+w=",
+        "lastModified": 1760971495,
+        "narHash": "sha256-IwnNtbNVrlZIHh7h4Wz6VP0Furxg9Hh0ycighvL5cZc=",
         "owner": "cachix",
         "repo": "cachix",
-        "rev": "47053aef762f452e816e44eb9a23fbc3827b241a",
+        "rev": "c5bfd933d1033672f51a863c47303fc0e093c2d2",
         "type": "github"
       },
       "original": {
@@ -44,16 +45,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1759795821,
-        "narHash": "sha256-rsb+6Wca43guzLL4Czoc89L394ZW9JZF2MShxaz2Sx4=",
+        "lastModified": 1764115230,
+        "narHash": "sha256-xfvW7aF2bDXDXzUeaSOXE+bARfcDbf4YCMVfNp8DTv0=",
         "owner": "cachix",
         "repo": "devenv",
-        "rev": "6880d8946d4a02b1fd2c74f2b6a342f45034b483",
+        "rev": "51440964cd26a47e90064f9d59aa230a5cefc88b",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "v1.10",
+        "ref": "v1.11.1",
         "repo": "devenv",
         "type": "github"
       }
@@ -61,11 +62,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1747046372,
-        "narHash": "sha256-CIVLLkVgvHYbgI2UpXvIIBJ12HWgX+fjA8Xf8PUmqCY=",
+        "lastModified": 1761588595,
+        "narHash": "sha256-XKUZz9zewJNUj46b4AJdiRZJAvSZ0Dqj2BNfXvFlJC4=",
         "owner": "edolstra",
         "repo": "flake-compat",
-        "rev": "9100a0f413b0c601e0533d1d94ffd501ce2e7885",
+        "rev": "f387cd2afec9419c8ee37694406ca490c3f34ee5",
         "type": "github"
       },
       "original": {
@@ -98,11 +99,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1756770412,
-        "narHash": "sha256-+uWLQZccFHwqpGqr2Yt5VsW/PbeJVTn9Dk6SHWhNRPw=",
+        "lastModified": 1760948891,
+        "narHash": "sha256-TmWcdiUUaWk8J4lpjzu4gCGxWY6/Ok7mOK4fIFfBuU4=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "4524271976b625a4a605beefd893f270620fd751",
+        "rev": "864599284fc7c0ba6357ed89ed5e2cd5040f0c04",
         "type": "github"
       },
       "original": {
@@ -116,11 +117,11 @@
         "nixpkgs-lib": "nixpkgs-lib"
       },
       "locked": {
-        "lastModified": 1762040540,
-        "narHash": "sha256-z5PlZ47j50VNF3R+IMS9LmzI5fYRGY/Z5O5tol1c9I4=",
+        "lastModified": 1763759067,
+        "narHash": "sha256-LlLt2Jo/gMNYAwOgdRQBrsRoOz7BPRkzvNaI/fzXi2Q=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "0010412d62a25d959151790968765a70c436598b",
+        "rev": "2cccadc7357c0ba201788ae99c4dfa90728ef5e0",
         "type": "github"
       },
       "original": {
@@ -163,11 +164,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1758108966,
-        "narHash": "sha256-ytw7ROXaWZ7OfwHrQ9xvjpUWeGVm86pwnEd1QhzawIo=",
+        "lastModified": 1760663237,
+        "narHash": "sha256-BflA6U4AM1bzuRMR8QqzPXqh8sWVCNDzOdsxXEguJIc=",
         "owner": "cachix",
         "repo": "git-hooks.nix",
-        "rev": "54df955a695a84cd47d4a43e08e1feaf90b1fd9b",
+        "rev": "ca5b894d3e3e151ffc1db040b6ce4dcc75d31c37",
         "type": "github"
       },
       "original": {
@@ -231,11 +232,11 @@
     },
     "import-tree": {
       "locked": {
-        "lastModified": 1761120675,
-        "narHash": "sha256-TEbh9zISiQcU82VwVoEbmXHnSGlUxTwvjJA9g9ErSDA=",
+        "lastModified": 1763762820,
+        "narHash": "sha256-ZvYKbFib3AEwiNMLsejb/CWs/OL/srFQ8AogkebEPF0=",
         "owner": "vic",
         "repo": "import-tree",
-        "rev": "a037ed2a58fc0ebed9e93b9ef79b0646e648f719",
+        "rev": "3c23749d8013ec6daa1d7255057590e9ca726646",
         "type": "github"
       },
       "original": {
@@ -270,16 +271,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1758763079,
-        "narHash": "sha256-Bx1A+lShhOWwMuy3uDzZQvYiBKBFcKwy6G6NEohhv6A=",
+        "lastModified": 1761648602,
+        "narHash": "sha256-H97KSB/luq/aGobKRuHahOvT1r7C03BgB6D5HBZsbN8=",
         "owner": "cachix",
         "repo": "nix",
-        "rev": "6f0140527c2b0346df4afad7497baa08decb929f",
+        "rev": "3e5644da6830ef65f0a2f7ec22830c46285bfff6",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "devenv-2.30.5",
+        "ref": "devenv-2.30.6",
         "repo": "nix",
         "type": "github"
       }
@@ -296,11 +297,11 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1762230076,
-        "narHash": "sha256-nvAAO37hbRHsRTu/Vo7Et6jezIyWRZXJ7tJIgj7sNX0=",
+        "lastModified": 1765401252,
+        "narHash": "sha256-PT72jzpeB5A6u6pfWLdyh/soPsmQF+H0/YImfg1DwYk=",
         "owner": "nixos",
         "repo": "nix",
-        "rev": "341c42f3212875722f41d03a37eb2bd62c1ce5f6",
+        "rev": "ccba158780b3d8957b7ef436a6cbc1ec08a0174e",
         "type": "github"
       },
       "original": {
@@ -311,11 +312,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1762111121,
-        "narHash": "sha256-4vhDuZ7OZaZmKKrnDpxLZZpGIJvAeMtK6FKLJYUtAdw=",
+        "lastModified": 1765186076,
+        "narHash": "sha256-hM20uyap1a0M9d344I692r+ik4gTMyj60cQWO+hAYP8=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "b3d51a0365f6695e7dd5cdf3e180604530ed33b4",
+        "rev": "addf7cf5f383a3101ecfba091b98d0a1263dc9b8",
         "type": "github"
       },
       "original": {
@@ -343,16 +344,16 @@
     },
     "nixpkgs-devenv": {
       "locked": {
-        "lastModified": 1758532697,
-        "narHash": "sha256-bhop0bR3u7DCw9/PtLCwr7GwEWDlBSxHp+eVQhCW9t4=",
+        "lastModified": 1761313199,
+        "narHash": "sha256-wCIACXbNtXAlwvQUo1Ed++loFALPjYUA3dpcUJiXO44=",
         "owner": "cachix",
         "repo": "devenv-nixpkgs",
-        "rev": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "rev": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "ref": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "repo": "devenv-nixpkgs",
         "type": "github"
       }
@@ -390,16 +391,16 @@
     },
     "nixpkgs-stable": {
       "locked": {
-        "lastModified": 1761999846,
-        "narHash": "sha256-IYlYnp4O4dzEpL77BD/lj5NnJy2J8qbHkNSFiPBCbqo=",
+        "lastModified": 1765311797,
+        "narHash": "sha256-mSD5Ob7a+T2RNjvPvOA1dkJHGVrNVl8ZOrAwBjKBDQo=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "3de8f8d73e35724bf9abef41f1bdbedda1e14a31",
+        "rev": "09eb77e94fa25202af8f3e81ddc7353d9970ac1b",
         "type": "github"
       },
       "original": {
         "owner": "nixos",
-        "ref": "nixos-25.05",
+        "ref": "nixos-25.11",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -436,11 +437,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1761311587,
-        "narHash": "sha256-Msq86cR5SjozQGCnC6H8C+0cD4rnx91BPltZ9KK613Y=",
+        "lastModified": 1762938485,
+        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
         "owner": "numtide",
         "repo": "treefmt-nix",
-        "rev": "2eddae033e4e74bf581c2d1dfa101f9033dbd2dc",
+        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
         "type": "github"
       },
       "original": {
diff --git a/src/generic/tools/nix/flake.nix.jinja b/src/generic/tools/nix/flake.nix.jinja
index fc699dd..63ecacf 100644
--- a/src/generic/tools/nix/flake.nix.jinja
+++ b/src/generic/tools/nix/flake.nix.jinja
@@ -54,7 +54,7 @@
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
 
     # Nixpkgs (stable NixOS branch)
-    nixpkgs-stable.url = "github:nixos/nixpkgs/nixos-25.05";
+    nixpkgs-stable.url = "github:nixos/nixpkgs/nixos-25.11";
 
     # Format the repo with nix-treefmt.
     treefmt-nix = {
@@ -65,12 +65,12 @@
     # The devenv module to create good development shells.
     # The `nixpkgs-devenv` must aligned with the pinned version.
     devenv = {
-      url = "github:cachix/devenv?ref=v1.10";
+      url = "github:cachix/devenv?ref=v1.11.1";
       inputs.nixpkgs.follows = "nixpkgs-devenv";
     };
     # This is the rolling nixpkgs with what devenv was tested.
     nixpkgs-devenv = {
-      url = "github:cachix/devenv-nixpkgs?ref=207a4cb0e1253c7658c6736becc6eb9cace1f25f";
+      url = "github:cachix/devenv-nixpkgs?ref=d1c30452ebecfc55185ae6d1c983c09da0c274ff";
     };
 
     # To build a base image with Nix.
diff --git a/src/go/tools/nix/flake.lock b/src/go/tools/nix/flake.lock
index a95f183..93f9f10 100644
--- a/src/go/tools/nix/flake.lock
+++ b/src/go/tools/nix/flake.lock
@@ -6,7 +6,8 @@
           "devenv"
         ],
         "flake-compat": [
-          "devenv"
+          "devenv",
+          "flake-compat"
         ],
         "git-hooks": [
           "devenv",
@@ -18,11 +19,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1752264895,
-        "narHash": "sha256-1zBPE/PNAkPNUsOWFET4J0cjlvziH8DOekesDmjND+w=",
+        "lastModified": 1760971495,
+        "narHash": "sha256-IwnNtbNVrlZIHh7h4Wz6VP0Furxg9Hh0ycighvL5cZc=",
         "owner": "cachix",
         "repo": "cachix",
-        "rev": "47053aef762f452e816e44eb9a23fbc3827b241a",
+        "rev": "c5bfd933d1033672f51a863c47303fc0e093c2d2",
         "type": "github"
       },
       "original": {
@@ -44,16 +45,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1759795821,
-        "narHash": "sha256-rsb+6Wca43guzLL4Czoc89L394ZW9JZF2MShxaz2Sx4=",
+        "lastModified": 1764115230,
+        "narHash": "sha256-xfvW7aF2bDXDXzUeaSOXE+bARfcDbf4YCMVfNp8DTv0=",
         "owner": "cachix",
         "repo": "devenv",
-        "rev": "6880d8946d4a02b1fd2c74f2b6a342f45034b483",
+        "rev": "51440964cd26a47e90064f9d59aa230a5cefc88b",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "v1.10",
+        "ref": "v1.11.1",
         "repo": "devenv",
         "type": "github"
       }
@@ -61,11 +62,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1747046372,
-        "narHash": "sha256-CIVLLkVgvHYbgI2UpXvIIBJ12HWgX+fjA8Xf8PUmqCY=",
+        "lastModified": 1761588595,
+        "narHash": "sha256-XKUZz9zewJNUj46b4AJdiRZJAvSZ0Dqj2BNfXvFlJC4=",
         "owner": "edolstra",
         "repo": "flake-compat",
-        "rev": "9100a0f413b0c601e0533d1d94ffd501ce2e7885",
+        "rev": "f387cd2afec9419c8ee37694406ca490c3f34ee5",
         "type": "github"
       },
       "original": {
@@ -98,11 +99,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1756770412,
-        "narHash": "sha256-+uWLQZccFHwqpGqr2Yt5VsW/PbeJVTn9Dk6SHWhNRPw=",
+        "lastModified": 1760948891,
+        "narHash": "sha256-TmWcdiUUaWk8J4lpjzu4gCGxWY6/Ok7mOK4fIFfBuU4=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "4524271976b625a4a605beefd893f270620fd751",
+        "rev": "864599284fc7c0ba6357ed89ed5e2cd5040f0c04",
         "type": "github"
       },
       "original": {
@@ -116,11 +117,11 @@
         "nixpkgs-lib": "nixpkgs-lib"
       },
       "locked": {
-        "lastModified": 1762040540,
-        "narHash": "sha256-z5PlZ47j50VNF3R+IMS9LmzI5fYRGY/Z5O5tol1c9I4=",
+        "lastModified": 1763759067,
+        "narHash": "sha256-LlLt2Jo/gMNYAwOgdRQBrsRoOz7BPRkzvNaI/fzXi2Q=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "0010412d62a25d959151790968765a70c436598b",
+        "rev": "2cccadc7357c0ba201788ae99c4dfa90728ef5e0",
         "type": "github"
       },
       "original": {
@@ -163,11 +164,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1758108966,
-        "narHash": "sha256-ytw7ROXaWZ7OfwHrQ9xvjpUWeGVm86pwnEd1QhzawIo=",
+        "lastModified": 1760663237,
+        "narHash": "sha256-BflA6U4AM1bzuRMR8QqzPXqh8sWVCNDzOdsxXEguJIc=",
         "owner": "cachix",
         "repo": "git-hooks.nix",
-        "rev": "54df955a695a84cd47d4a43e08e1feaf90b1fd9b",
+        "rev": "ca5b894d3e3e151ffc1db040b6ce4dcc75d31c37",
         "type": "github"
       },
       "original": {
@@ -231,11 +232,11 @@
     },
     "import-tree": {
       "locked": {
-        "lastModified": 1761120675,
-        "narHash": "sha256-TEbh9zISiQcU82VwVoEbmXHnSGlUxTwvjJA9g9ErSDA=",
+        "lastModified": 1763762820,
+        "narHash": "sha256-ZvYKbFib3AEwiNMLsejb/CWs/OL/srFQ8AogkebEPF0=",
         "owner": "vic",
         "repo": "import-tree",
-        "rev": "a037ed2a58fc0ebed9e93b9ef79b0646e648f719",
+        "rev": "3c23749d8013ec6daa1d7255057590e9ca726646",
         "type": "github"
       },
       "original": {
@@ -270,16 +271,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1758763079,
-        "narHash": "sha256-Bx1A+lShhOWwMuy3uDzZQvYiBKBFcKwy6G6NEohhv6A=",
+        "lastModified": 1761648602,
+        "narHash": "sha256-H97KSB/luq/aGobKRuHahOvT1r7C03BgB6D5HBZsbN8=",
         "owner": "cachix",
         "repo": "nix",
-        "rev": "6f0140527c2b0346df4afad7497baa08decb929f",
+        "rev": "3e5644da6830ef65f0a2f7ec22830c46285bfff6",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "devenv-2.30.5",
+        "ref": "devenv-2.30.6",
         "repo": "nix",
         "type": "github"
       }
@@ -296,11 +297,11 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1762230076,
-        "narHash": "sha256-nvAAO37hbRHsRTu/Vo7Et6jezIyWRZXJ7tJIgj7sNX0=",
+        "lastModified": 1765401252,
+        "narHash": "sha256-PT72jzpeB5A6u6pfWLdyh/soPsmQF+H0/YImfg1DwYk=",
         "owner": "nixos",
         "repo": "nix",
-        "rev": "341c42f3212875722f41d03a37eb2bd62c1ce5f6",
+        "rev": "ccba158780b3d8957b7ef436a6cbc1ec08a0174e",
         "type": "github"
       },
       "original": {
@@ -311,11 +312,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1762111121,
-        "narHash": "sha256-4vhDuZ7OZaZmKKrnDpxLZZpGIJvAeMtK6FKLJYUtAdw=",
+        "lastModified": 1765186076,
+        "narHash": "sha256-hM20uyap1a0M9d344I692r+ik4gTMyj60cQWO+hAYP8=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "b3d51a0365f6695e7dd5cdf3e180604530ed33b4",
+        "rev": "addf7cf5f383a3101ecfba091b98d0a1263dc9b8",
         "type": "github"
       },
       "original": {
@@ -343,16 +344,16 @@
     },
     "nixpkgs-devenv": {
       "locked": {
-        "lastModified": 1758532697,
-        "narHash": "sha256-bhop0bR3u7DCw9/PtLCwr7GwEWDlBSxHp+eVQhCW9t4=",
+        "lastModified": 1761313199,
+        "narHash": "sha256-wCIACXbNtXAlwvQUo1Ed++loFALPjYUA3dpcUJiXO44=",
         "owner": "cachix",
         "repo": "devenv-nixpkgs",
-        "rev": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "rev": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "ref": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "repo": "devenv-nixpkgs",
         "type": "github"
       }
@@ -390,16 +391,16 @@
     },
     "nixpkgs-stable": {
       "locked": {
-        "lastModified": 1761999846,
-        "narHash": "sha256-IYlYnp4O4dzEpL77BD/lj5NnJy2J8qbHkNSFiPBCbqo=",
+        "lastModified": 1765311797,
+        "narHash": "sha256-mSD5Ob7a+T2RNjvPvOA1dkJHGVrNVl8ZOrAwBjKBDQo=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "3de8f8d73e35724bf9abef41f1bdbedda1e14a31",
+        "rev": "09eb77e94fa25202af8f3e81ddc7353d9970ac1b",
         "type": "github"
       },
       "original": {
         "owner": "nixos",
-        "ref": "nixos-25.05",
+        "ref": "nixos-25.11",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -436,11 +437,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1761311587,
-        "narHash": "sha256-Msq86cR5SjozQGCnC6H8C+0cD4rnx91BPltZ9KK613Y=",
+        "lastModified": 1762938485,
+        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
         "owner": "numtide",
         "repo": "treefmt-nix",
-        "rev": "2eddae033e4e74bf581c2d1dfa101f9033dbd2dc",
+        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
         "type": "github"
       },
       "original": {
diff --git a/src/go/tools/nix/toolchains/toolchain-go.nix b/src/go/tools/nix/toolchains/toolchain-go.nix
index 645310a..9aa1ecf 100644
--- a/src/go/tools/nix/toolchains/toolchain-go.nix
+++ b/src/go/tools/nix/toolchains/toolchain-go.nix
@@ -18,7 +18,7 @@ in
 
         tools.packages = [
           # Go specific tools which should be compiled with the chosen
-          # go `package`.
+          # go `package`. Default is set to `tools.packagesDefaults`.
         ];
 
       };
diff --git a/src/python/src/{{ module_name }}/cli.py b/src/python/src/{{ module_name }}/cli.py
index 6f8c82c..b855d20 100644
--- a/src/python/src/{{ module_name }}/cli.py	
+++ b/src/python/src/{{ module_name }}/cli.py	
@@ -1,5 +1,36 @@
+import numpy as np
+
+
+def numpy_demo_calculation():
+    print("--- NumPy Demo Calculation ---")
+
+    random_array = np.random.randint(0, 101, size=10)
+    print(f"Original array: {random_array}")
+
+    array_mean = np.mean(random_array)
+    print(f"Mean of the array: {array_mean:.2f}")  # Format to 2 decimal places
+
+    array_std_dev = np.std(random_array)
+    print(
+        f"Standard deviation of the array: {array_std_dev:.2f}"
+    )  # Format to 2 decimal places
+
+    random_array = np.random.randint(0, 101, size=10)
+    print(f"Original array: {random_array}")
+
+    array_mean = np.mean(random_array)
+    print(f"Mean of the array: {array_mean:.2f}")  # Format to 2 decimal places
+
+    array_std_dev = np.std(random_array)
+    print(
+        f"Standard deviation of the array: {array_std_dev:.2f}"
+    )  # Format to 2 decimal places
+
+    print("--- End of Demo ---")
+
+
 def main():
-    print("Running my tool.")
+    numpy_demo_calculation()
 
 
 if __name__ == "__main__":
diff --git a/src/python/tools/nix/flake.lock b/src/python/tools/nix/flake.lock
index ff0a35d..95f6793 100644
--- a/src/python/tools/nix/flake.lock
+++ b/src/python/tools/nix/flake.lock
@@ -6,7 +6,8 @@
           "devenv"
         ],
         "flake-compat": [
-          "devenv"
+          "devenv",
+          "flake-compat"
         ],
         "git-hooks": [
           "devenv",
@@ -18,11 +19,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1752264895,
-        "narHash": "sha256-1zBPE/PNAkPNUsOWFET4J0cjlvziH8DOekesDmjND+w=",
+        "lastModified": 1760971495,
+        "narHash": "sha256-IwnNtbNVrlZIHh7h4Wz6VP0Furxg9Hh0ycighvL5cZc=",
         "owner": "cachix",
         "repo": "cachix",
-        "rev": "47053aef762f452e816e44eb9a23fbc3827b241a",
+        "rev": "c5bfd933d1033672f51a863c47303fc0e093c2d2",
         "type": "github"
       },
       "original": {
@@ -44,16 +45,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1759795821,
-        "narHash": "sha256-rsb+6Wca43guzLL4Czoc89L394ZW9JZF2MShxaz2Sx4=",
+        "lastModified": 1764115230,
+        "narHash": "sha256-xfvW7aF2bDXDXzUeaSOXE+bARfcDbf4YCMVfNp8DTv0=",
         "owner": "cachix",
         "repo": "devenv",
-        "rev": "6880d8946d4a02b1fd2c74f2b6a342f45034b483",
+        "rev": "51440964cd26a47e90064f9d59aa230a5cefc88b",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "v1.10",
+        "ref": "v1.11.1",
         "repo": "devenv",
         "type": "github"
       }
@@ -61,11 +62,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1747046372,
-        "narHash": "sha256-CIVLLkVgvHYbgI2UpXvIIBJ12HWgX+fjA8Xf8PUmqCY=",
+        "lastModified": 1761588595,
+        "narHash": "sha256-XKUZz9zewJNUj46b4AJdiRZJAvSZ0Dqj2BNfXvFlJC4=",
         "owner": "edolstra",
         "repo": "flake-compat",
-        "rev": "9100a0f413b0c601e0533d1d94ffd501ce2e7885",
+        "rev": "f387cd2afec9419c8ee37694406ca490c3f34ee5",
         "type": "github"
       },
       "original": {
@@ -114,11 +115,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1756770412,
-        "narHash": "sha256-+uWLQZccFHwqpGqr2Yt5VsW/PbeJVTn9Dk6SHWhNRPw=",
+        "lastModified": 1760948891,
+        "narHash": "sha256-TmWcdiUUaWk8J4lpjzu4gCGxWY6/Ok7mOK4fIFfBuU4=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "4524271976b625a4a605beefd893f270620fd751",
+        "rev": "864599284fc7c0ba6357ed89ed5e2cd5040f0c04",
         "type": "github"
       },
       "original": {
@@ -132,11 +133,11 @@
         "nixpkgs-lib": "nixpkgs-lib"
       },
       "locked": {
-        "lastModified": 1762040540,
-        "narHash": "sha256-z5PlZ47j50VNF3R+IMS9LmzI5fYRGY/Z5O5tol1c9I4=",
+        "lastModified": 1763759067,
+        "narHash": "sha256-LlLt2Jo/gMNYAwOgdRQBrsRoOz7BPRkzvNaI/fzXi2Q=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "0010412d62a25d959151790968765a70c436598b",
+        "rev": "2cccadc7357c0ba201788ae99c4dfa90728ef5e0",
         "type": "github"
       },
       "original": {
@@ -179,11 +180,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1758108966,
-        "narHash": "sha256-ytw7ROXaWZ7OfwHrQ9xvjpUWeGVm86pwnEd1QhzawIo=",
+        "lastModified": 1760663237,
+        "narHash": "sha256-BflA6U4AM1bzuRMR8QqzPXqh8sWVCNDzOdsxXEguJIc=",
         "owner": "cachix",
         "repo": "git-hooks.nix",
-        "rev": "54df955a695a84cd47d4a43e08e1feaf90b1fd9b",
+        "rev": "ca5b894d3e3e151ffc1db040b6ce4dcc75d31c37",
         "type": "github"
       },
       "original": {
@@ -247,11 +248,11 @@
     },
     "import-tree": {
       "locked": {
-        "lastModified": 1761120675,
-        "narHash": "sha256-TEbh9zISiQcU82VwVoEbmXHnSGlUxTwvjJA9g9ErSDA=",
+        "lastModified": 1763762820,
+        "narHash": "sha256-ZvYKbFib3AEwiNMLsejb/CWs/OL/srFQ8AogkebEPF0=",
         "owner": "vic",
         "repo": "import-tree",
-        "rev": "a037ed2a58fc0ebed9e93b9ef79b0646e648f719",
+        "rev": "3c23749d8013ec6daa1d7255057590e9ca726646",
         "type": "github"
       },
       "original": {
@@ -286,16 +287,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1758763079,
-        "narHash": "sha256-Bx1A+lShhOWwMuy3uDzZQvYiBKBFcKwy6G6NEohhv6A=",
+        "lastModified": 1761648602,
+        "narHash": "sha256-H97KSB/luq/aGobKRuHahOvT1r7C03BgB6D5HBZsbN8=",
         "owner": "cachix",
         "repo": "nix",
-        "rev": "6f0140527c2b0346df4afad7497baa08decb929f",
+        "rev": "3e5644da6830ef65f0a2f7ec22830c46285bfff6",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "devenv-2.30.5",
+        "ref": "devenv-2.30.6",
         "repo": "nix",
         "type": "github"
       }
@@ -312,11 +313,11 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1762230076,
-        "narHash": "sha256-nvAAO37hbRHsRTu/Vo7Et6jezIyWRZXJ7tJIgj7sNX0=",
+        "lastModified": 1765401252,
+        "narHash": "sha256-PT72jzpeB5A6u6pfWLdyh/soPsmQF+H0/YImfg1DwYk=",
         "owner": "nixos",
         "repo": "nix",
-        "rev": "341c42f3212875722f41d03a37eb2bd62c1ce5f6",
+        "rev": "ccba158780b3d8957b7ef436a6cbc1ec08a0174e",
         "type": "github"
       },
       "original": {
@@ -327,11 +328,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1762111121,
-        "narHash": "sha256-4vhDuZ7OZaZmKKrnDpxLZZpGIJvAeMtK6FKLJYUtAdw=",
+        "lastModified": 1765186076,
+        "narHash": "sha256-hM20uyap1a0M9d344I692r+ik4gTMyj60cQWO+hAYP8=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "b3d51a0365f6695e7dd5cdf3e180604530ed33b4",
+        "rev": "addf7cf5f383a3101ecfba091b98d0a1263dc9b8",
         "type": "github"
       },
       "original": {
@@ -359,16 +360,16 @@
     },
     "nixpkgs-devenv": {
       "locked": {
-        "lastModified": 1758532697,
-        "narHash": "sha256-bhop0bR3u7DCw9/PtLCwr7GwEWDlBSxHp+eVQhCW9t4=",
+        "lastModified": 1761313199,
+        "narHash": "sha256-wCIACXbNtXAlwvQUo1Ed++loFALPjYUA3dpcUJiXO44=",
         "owner": "cachix",
         "repo": "devenv-nixpkgs",
-        "rev": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "rev": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "ref": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "repo": "devenv-nixpkgs",
         "type": "github"
       }
@@ -396,11 +397,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1761999567,
-        "narHash": "sha256-NEisnXdISmaM5LzX1RatpKR4fa6nlAxkR7QJniFq0vg=",
+        "lastModified": 1765052656,
+        "narHash": "sha256-DrMjrjxMttbGDoVxr/xke0ihd5GVd6fyUVsjuepEsCc=",
         "owner": "cachix",
         "repo": "nixpkgs-python",
-        "rev": "100c43175443402084f557154b06f2745995e742",
+        "rev": "04b27dbad2e004cb237db202f21154eea3c4f89f",
         "type": "github"
       },
       "original": {
@@ -427,16 +428,16 @@
     },
     "nixpkgs-stable": {
       "locked": {
-        "lastModified": 1761999846,
-        "narHash": "sha256-IYlYnp4O4dzEpL77BD/lj5NnJy2J8qbHkNSFiPBCbqo=",
+        "lastModified": 1765311797,
+        "narHash": "sha256-mSD5Ob7a+T2RNjvPvOA1dkJHGVrNVl8ZOrAwBjKBDQo=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "3de8f8d73e35724bf9abef41f1bdbedda1e14a31",
+        "rev": "09eb77e94fa25202af8f3e81ddc7353d9970ac1b",
         "type": "github"
       },
       "original": {
         "owner": "nixos",
-        "ref": "nixos-25.05",
+        "ref": "nixos-25.11",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -474,11 +475,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1761311587,
-        "narHash": "sha256-Msq86cR5SjozQGCnC6H8C+0cD4rnx91BPltZ9KK613Y=",
+        "lastModified": 1762938485,
+        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
         "owner": "numtide",
         "repo": "treefmt-nix",
-        "rev": "2eddae033e4e74bf581c2d1dfa101f9033dbd2dc",
+        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
         "type": "github"
       },
       "original": {
diff --git a/src/python/tools/nix/toolchains/toolchain-python.nix b/src/python/tools/nix/toolchains/toolchain-python.nix
index 522767b..238333b 100644
--- a/src/python/tools/nix/toolchains/toolchain-python.nix
+++ b/src/python/tools/nix/toolchains/toolchain-python.nix
@@ -29,7 +29,12 @@
       languages.python = {
         enable = true;
 
-        package = pkgs.python313;
+        # Heavy modules relying (CYTHON, ext. shared libraries etc)
+        # should be built by Nix.
+        package = pkgs.python313.withPackages (p: [
+          p.numpy
+          p.matplotlib
+        ]);
 
         directory = builtins.toString self.lib.fs.repoRoot;
 
diff --git a/src/rust/tools/nix/flake.lock b/src/rust/tools/nix/flake.lock
index a21f7e9..d24cde2 100644
--- a/src/rust/tools/nix/flake.lock
+++ b/src/rust/tools/nix/flake.lock
@@ -6,7 +6,8 @@
           "devenv"
         ],
         "flake-compat": [
-          "devenv"
+          "devenv",
+          "flake-compat"
         ],
         "git-hooks": [
           "devenv",
@@ -18,11 +19,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1752264895,
-        "narHash": "sha256-1zBPE/PNAkPNUsOWFET4J0cjlvziH8DOekesDmjND+w=",
+        "lastModified": 1760971495,
+        "narHash": "sha256-IwnNtbNVrlZIHh7h4Wz6VP0Furxg9Hh0ycighvL5cZc=",
         "owner": "cachix",
         "repo": "cachix",
-        "rev": "47053aef762f452e816e44eb9a23fbc3827b241a",
+        "rev": "c5bfd933d1033672f51a863c47303fc0e093c2d2",
         "type": "github"
       },
       "original": {
@@ -44,16 +45,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1759795821,
-        "narHash": "sha256-rsb+6Wca43guzLL4Czoc89L394ZW9JZF2MShxaz2Sx4=",
+        "lastModified": 1764115230,
+        "narHash": "sha256-xfvW7aF2bDXDXzUeaSOXE+bARfcDbf4YCMVfNp8DTv0=",
         "owner": "cachix",
         "repo": "devenv",
-        "rev": "6880d8946d4a02b1fd2c74f2b6a342f45034b483",
+        "rev": "51440964cd26a47e90064f9d59aa230a5cefc88b",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "v1.10",
+        "ref": "v1.11.1",
         "repo": "devenv",
         "type": "github"
       }
@@ -61,11 +62,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1747046372,
-        "narHash": "sha256-CIVLLkVgvHYbgI2UpXvIIBJ12HWgX+fjA8Xf8PUmqCY=",
+        "lastModified": 1761588595,
+        "narHash": "sha256-XKUZz9zewJNUj46b4AJdiRZJAvSZ0Dqj2BNfXvFlJC4=",
         "owner": "edolstra",
         "repo": "flake-compat",
-        "rev": "9100a0f413b0c601e0533d1d94ffd501ce2e7885",
+        "rev": "f387cd2afec9419c8ee37694406ca490c3f34ee5",
         "type": "github"
       },
       "original": {
@@ -98,11 +99,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1756770412,
-        "narHash": "sha256-+uWLQZccFHwqpGqr2Yt5VsW/PbeJVTn9Dk6SHWhNRPw=",
+        "lastModified": 1760948891,
+        "narHash": "sha256-TmWcdiUUaWk8J4lpjzu4gCGxWY6/Ok7mOK4fIFfBuU4=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "4524271976b625a4a605beefd893f270620fd751",
+        "rev": "864599284fc7c0ba6357ed89ed5e2cd5040f0c04",
         "type": "github"
       },
       "original": {
@@ -116,11 +117,11 @@
         "nixpkgs-lib": "nixpkgs-lib"
       },
       "locked": {
-        "lastModified": 1762040540,
-        "narHash": "sha256-z5PlZ47j50VNF3R+IMS9LmzI5fYRGY/Z5O5tol1c9I4=",
+        "lastModified": 1763759067,
+        "narHash": "sha256-LlLt2Jo/gMNYAwOgdRQBrsRoOz7BPRkzvNaI/fzXi2Q=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "0010412d62a25d959151790968765a70c436598b",
+        "rev": "2cccadc7357c0ba201788ae99c4dfa90728ef5e0",
         "type": "github"
       },
       "original": {
@@ -163,11 +164,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1758108966,
-        "narHash": "sha256-ytw7ROXaWZ7OfwHrQ9xvjpUWeGVm86pwnEd1QhzawIo=",
+        "lastModified": 1760663237,
+        "narHash": "sha256-BflA6U4AM1bzuRMR8QqzPXqh8sWVCNDzOdsxXEguJIc=",
         "owner": "cachix",
         "repo": "git-hooks.nix",
-        "rev": "54df955a695a84cd47d4a43e08e1feaf90b1fd9b",
+        "rev": "ca5b894d3e3e151ffc1db040b6ce4dcc75d31c37",
         "type": "github"
       },
       "original": {
@@ -231,11 +232,11 @@
     },
     "import-tree": {
       "locked": {
-        "lastModified": 1761120675,
-        "narHash": "sha256-TEbh9zISiQcU82VwVoEbmXHnSGlUxTwvjJA9g9ErSDA=",
+        "lastModified": 1763762820,
+        "narHash": "sha256-ZvYKbFib3AEwiNMLsejb/CWs/OL/srFQ8AogkebEPF0=",
         "owner": "vic",
         "repo": "import-tree",
-        "rev": "a037ed2a58fc0ebed9e93b9ef79b0646e648f719",
+        "rev": "3c23749d8013ec6daa1d7255057590e9ca726646",
         "type": "github"
       },
       "original": {
@@ -270,16 +271,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1758763079,
-        "narHash": "sha256-Bx1A+lShhOWwMuy3uDzZQvYiBKBFcKwy6G6NEohhv6A=",
+        "lastModified": 1761648602,
+        "narHash": "sha256-H97KSB/luq/aGobKRuHahOvT1r7C03BgB6D5HBZsbN8=",
         "owner": "cachix",
         "repo": "nix",
-        "rev": "6f0140527c2b0346df4afad7497baa08decb929f",
+        "rev": "3e5644da6830ef65f0a2f7ec22830c46285bfff6",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "devenv-2.30.5",
+        "ref": "devenv-2.30.6",
         "repo": "nix",
         "type": "github"
       }
@@ -296,11 +297,11 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1762230076,
-        "narHash": "sha256-nvAAO37hbRHsRTu/Vo7Et6jezIyWRZXJ7tJIgj7sNX0=",
+        "lastModified": 1765401252,
+        "narHash": "sha256-PT72jzpeB5A6u6pfWLdyh/soPsmQF+H0/YImfg1DwYk=",
         "owner": "nixos",
         "repo": "nix",
-        "rev": "341c42f3212875722f41d03a37eb2bd62c1ce5f6",
+        "rev": "ccba158780b3d8957b7ef436a6cbc1ec08a0174e",
         "type": "github"
       },
       "original": {
@@ -311,11 +312,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1762111121,
-        "narHash": "sha256-4vhDuZ7OZaZmKKrnDpxLZZpGIJvAeMtK6FKLJYUtAdw=",
+        "lastModified": 1765186076,
+        "narHash": "sha256-hM20uyap1a0M9d344I692r+ik4gTMyj60cQWO+hAYP8=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "b3d51a0365f6695e7dd5cdf3e180604530ed33b4",
+        "rev": "addf7cf5f383a3101ecfba091b98d0a1263dc9b8",
         "type": "github"
       },
       "original": {
@@ -343,16 +344,16 @@
     },
     "nixpkgs-devenv": {
       "locked": {
-        "lastModified": 1758532697,
-        "narHash": "sha256-bhop0bR3u7DCw9/PtLCwr7GwEWDlBSxHp+eVQhCW9t4=",
+        "lastModified": 1761313199,
+        "narHash": "sha256-wCIACXbNtXAlwvQUo1Ed++loFALPjYUA3dpcUJiXO44=",
         "owner": "cachix",
         "repo": "devenv-nixpkgs",
-        "rev": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "rev": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "207a4cb0e1253c7658c6736becc6eb9cace1f25f",
+        "ref": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "repo": "devenv-nixpkgs",
         "type": "github"
       }
@@ -390,16 +391,16 @@
     },
     "nixpkgs-stable": {
       "locked": {
-        "lastModified": 1761999846,
-        "narHash": "sha256-IYlYnp4O4dzEpL77BD/lj5NnJy2J8qbHkNSFiPBCbqo=",
+        "lastModified": 1765311797,
+        "narHash": "sha256-mSD5Ob7a+T2RNjvPvOA1dkJHGVrNVl8ZOrAwBjKBDQo=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "3de8f8d73e35724bf9abef41f1bdbedda1e14a31",
+        "rev": "09eb77e94fa25202af8f3e81ddc7353d9970ac1b",
         "type": "github"
       },
       "original": {
         "owner": "nixos",
-        "ref": "nixos-25.05",
+        "ref": "nixos-25.11",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -425,11 +426,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1762223900,
-        "narHash": "sha256-caxpESVH71mdrdihYvQZ9rTZPZqW0GyEG9un7MgpyRM=",
+        "lastModified": 1765465581,
+        "narHash": "sha256-fCXT0aZXmTalM3NPCTedVs9xb0egBG5BOZkcrYo5PGE=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "cfe1598d69a42a5edb204770e71b8df77efef2c3",
+        "rev": "99cc5667eece98bb35dcf35f7e511031a8b7a125",
         "type": "github"
       },
       "original": {
@@ -457,11 +458,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1761311587,
-        "narHash": "sha256-Msq86cR5SjozQGCnC6H8C+0cD4rnx91BPltZ9KK613Y=",
+        "lastModified": 1762938485,
+        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
         "owner": "numtide",
         "repo": "treefmt-nix",
-        "rev": "2eddae033e4e74bf581c2d1dfa101f9033dbd2dc",
+        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
         "type": "github"
       },
       "original": {
diff --git a/tools/just/maintenance.just b/tools/just/maintenance.just
index cc87801..010a9a1 100644
--- a/tools/just/maintenance.just
+++ b/tools/just/maintenance.just
@@ -52,7 +52,10 @@ test template="python": ci-setup setup
     ci::print_info "Running test '{{template}}'"
     ci::print_info "======================"
     build_dir="{{output_dir}}/{{template}}"
-    cd "{{root_dir}}" && rm -rf "$build_dir"
+    # Go template has `read-only` Go modules cache, e.g `chown.`
+    cd "{{root_dir}}" &&
+        chown -R +w "$build_dir" &&
+        rm -rf "$build_dir"
 
     uv run copier copy --trust -w  \
         --data "project_language={{template}}" \
diff --git a/tools/nix/flake.lock b/tools/nix/flake.lock
index ae7cb16..44028d1 100644
--- a/tools/nix/flake.lock
+++ b/tools/nix/flake.lock
@@ -6,7 +6,8 @@
           "devenv"
         ],
         "flake-compat": [
-          "devenv"
+          "devenv",
+          "flake-compat"
         ],
         "git-hooks": [
           "devenv",
@@ -18,11 +19,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1748883665,
-        "narHash": "sha256-R0W7uAg+BLoHjMRMQ8+oiSbTq8nkGz5RDpQ+ZfxxP3A=",
+        "lastModified": 1760971495,
+        "narHash": "sha256-IwnNtbNVrlZIHh7h4Wz6VP0Furxg9Hh0ycighvL5cZc=",
         "owner": "cachix",
         "repo": "cachix",
-        "rev": "f707778d902af4d62d8dd92c269f8e70de09acbe",
+        "rev": "c5bfd933d1033672f51a863c47303fc0e093c2d2",
         "type": "github"
       },
       "original": {
@@ -36,6 +37,7 @@
       "inputs": {
         "cachix": "cachix",
         "flake-compat": "flake-compat",
+        "flake-parts": "flake-parts",
         "git-hooks": "git-hooks",
         "nix": "nix",
         "nixpkgs": [
@@ -43,16 +45,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1753648694,
-        "narHash": "sha256-YsSFlVWUu4RSYnObqcBJ4Mr3bJVVhuFhaQAktHytBAI=",
+        "lastModified": 1764115230,
+        "narHash": "sha256-xfvW7aF2bDXDXzUeaSOXE+bARfcDbf4YCMVfNp8DTv0=",
         "owner": "cachix",
         "repo": "devenv",
-        "rev": "78bb7d169db0de8e11b9a9983a347d51bdf0f80e",
+        "rev": "51440964cd26a47e90064f9d59aa230a5cefc88b",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "v1.8.1",
+        "ref": "v1.11.1",
         "repo": "devenv",
         "type": "github"
       }
@@ -60,11 +62,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1747046372,
-        "narHash": "sha256-CIVLLkVgvHYbgI2UpXvIIBJ12HWgX+fjA8Xf8PUmqCY=",
+        "lastModified": 1761588595,
+        "narHash": "sha256-XKUZz9zewJNUj46b4AJdiRZJAvSZ0Dqj2BNfXvFlJC4=",
         "owner": "edolstra",
         "repo": "flake-compat",
-        "rev": "9100a0f413b0c601e0533d1d94ffd501ce2e7885",
+        "rev": "f387cd2afec9419c8ee37694406ca490c3f34ee5",
         "type": "github"
       },
       "original": {
@@ -109,16 +111,15 @@
       "inputs": {
         "nixpkgs-lib": [
           "devenv",
-          "nix",
           "nixpkgs"
         ]
       },
       "locked": {
-        "lastModified": 1733312601,
-        "narHash": "sha256-4pDvzqnegAfRkPwO3wmwBhVi/Sye1mzps0zHWYnP88c=",
+        "lastModified": 1760948891,
+        "narHash": "sha256-TmWcdiUUaWk8J4lpjzu4gCGxWY6/Ok7mOK4fIFfBuU4=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "205b12d8b7cd4802fbcb8e8ef6a0f1408781a4f9",
+        "rev": "864599284fc7c0ba6357ed89ed5e2cd5040f0c04",
         "type": "github"
       },
       "original": {
@@ -132,11 +133,11 @@
         "nixpkgs-lib": "nixpkgs-lib"
       },
       "locked": {
-        "lastModified": 1754487366,
-        "narHash": "sha256-pHYj8gUBapuUzKV/kN/tR3Zvqc7o6gdFB9XKXIp1SQ8=",
+        "lastModified": 1763759067,
+        "narHash": "sha256-LlLt2Jo/gMNYAwOgdRQBrsRoOz7BPRkzvNaI/fzXi2Q=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "af66ad14b28a127c5c0f3bbb298218fc63528a18",
+        "rev": "2cccadc7357c0ba201788ae99c4dfa90728ef5e0",
         "type": "github"
       },
       "original": {
@@ -179,11 +180,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1750779888,
-        "narHash": "sha256-wibppH3g/E2lxU43ZQHC5yA/7kIKLGxVEnsnVK1BtRg=",
+        "lastModified": 1760663237,
+        "narHash": "sha256-BflA6U4AM1bzuRMR8QqzPXqh8sWVCNDzOdsxXEguJIc=",
         "owner": "cachix",
         "repo": "git-hooks.nix",
-        "rev": "16ec914f6fb6f599ce988427d9d94efddf25fe6d",
+        "rev": "ca5b894d3e3e151ffc1db040b6ce4dcc75d31c37",
         "type": "github"
       },
       "original": {
@@ -247,11 +248,11 @@
     },
     "import-tree": {
       "locked": {
-        "lastModified": 1752730890,
-        "narHash": "sha256-GES8fapSLGz36MMPRVNkSUWXUTtqvGQNXHjRmRLfJUY=",
+        "lastModified": 1763762820,
+        "narHash": "sha256-ZvYKbFib3AEwiNMLsejb/CWs/OL/srFQ8AogkebEPF0=",
         "owner": "vic",
         "repo": "import-tree",
-        "rev": "6ebb8cb87987b20264c09296166543fd3761d274",
+        "rev": "3c23749d8013ec6daa1d7255057590e9ca726646",
         "type": "github"
       },
       "original": {
@@ -266,7 +267,10 @@
           "devenv",
           "flake-compat"
         ],
-        "flake-parts": "flake-parts",
+        "flake-parts": [
+          "devenv",
+          "flake-parts"
+        ],
         "git-hooks-nix": [
           "devenv",
           "git-hooks"
@@ -283,16 +287,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1752773918,
-        "narHash": "sha256-dOi/M6yNeuJlj88exI+7k154z+hAhFcuB8tZktiW7rg=",
+        "lastModified": 1761648602,
+        "narHash": "sha256-H97KSB/luq/aGobKRuHahOvT1r7C03BgB6D5HBZsbN8=",
         "owner": "cachix",
         "repo": "nix",
-        "rev": "031c3cf42d2e9391eee373507d8c12e0f9606779",
+        "rev": "3e5644da6830ef65f0a2f7ec22830c46285bfff6",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "devenv-2.30",
+        "ref": "devenv-2.30.6",
         "repo": "nix",
         "type": "github"
       }
@@ -309,11 +313,11 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1754896535,
-        "narHash": "sha256-0XpywJCHdw/HNeXP/3qEOM76J3hmbrDzUbspktUEZ28=",
+        "lastModified": 1765401252,
+        "narHash": "sha256-PT72jzpeB5A6u6pfWLdyh/soPsmQF+H0/YImfg1DwYk=",
         "owner": "nixos",
         "repo": "nix",
-        "rev": "867b69f53324226c35455471f3b10f2ffd12e67c",
+        "rev": "ccba158780b3d8957b7ef436a6cbc1ec08a0174e",
         "type": "github"
       },
       "original": {
@@ -324,11 +328,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1754725699,
-        "narHash": "sha256-iAcj9T/Y+3DBy2J0N+yF9XQQQ8IEb5swLFzs23CdP88=",
+        "lastModified": 1765186076,
+        "narHash": "sha256-hM20uyap1a0M9d344I692r+ik4gTMyj60cQWO+hAYP8=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "85dbfc7aaf52ecb755f87e577ddbe6dbbdbc1054",
+        "rev": "addf7cf5f383a3101ecfba091b98d0a1263dc9b8",
         "type": "github"
       },
       "original": {
@@ -356,27 +360,27 @@
     },
     "nixpkgs-devenv": {
       "locked": {
-        "lastModified": 1750441195,
-        "narHash": "sha256-yke+pm+MdgRb6c0dPt8MgDhv7fcBbdjmv1ZceNTyzKg=",
+        "lastModified": 1761313199,
+        "narHash": "sha256-wCIACXbNtXAlwvQUo1Ed++loFALPjYUA3dpcUJiXO44=",
         "owner": "cachix",
         "repo": "devenv-nixpkgs",
-        "rev": "0ceffe312871b443929ff3006960d29b120dc627",
+        "rev": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "type": "github"
       },
       "original": {
         "owner": "cachix",
-        "ref": "0ceffe312871b443929ff3006960d29b120dc627",
+        "ref": "d1c30452ebecfc55185ae6d1c983c09da0c274ff",
         "repo": "devenv-nixpkgs",
         "type": "github"
       }
     },
     "nixpkgs-lib": {
       "locked": {
-        "lastModified": 1753579242,
-        "narHash": "sha256-zvaMGVn14/Zz8hnp4VWT9xVnhc8vuL3TStRqwk22biA=",
+        "lastModified": 1761765539,
+        "narHash": "sha256-b0yj6kfvO8ApcSE+QmA6mUfu8IYG6/uU28OFn4PaC8M=",
         "owner": "nix-community",
         "repo": "nixpkgs.lib",
-        "rev": "0f36c44e01a6129be94e3ade315a5883f0228a6e",
+        "rev": "719359f4562934ae99f5443f20aa06c2ffff91fc",
         "type": "github"
       },
       "original": {
@@ -393,11 +397,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1754518819,
-        "narHash": "sha256-5gMAYsUgl46Y9ez9CtEQrqqWKGtzjzXIMR+pcrAr7aw=",
+        "lastModified": 1765052656,
+        "narHash": "sha256-DrMjrjxMttbGDoVxr/xke0ihd5GVd6fyUVsjuepEsCc=",
         "owner": "cachix",
         "repo": "nixpkgs-python",
-        "rev": "4253cbbd2b36ec8021962726c95ebdf874fd26af",
+        "rev": "04b27dbad2e004cb237db202f21154eea3c4f89f",
         "type": "github"
       },
       "original": {
@@ -424,11 +428,11 @@
     },
     "nixpkgs-stable": {
       "locked": {
-        "lastModified": 1754767907,
-        "narHash": "sha256-8OnUzRQZkqtUol9vuUuQC30hzpMreKptNyET2T9lB6g=",
+        "lastModified": 1765363881,
+        "narHash": "sha256-3C3xWn8/2Zzr7sxVBmpc1H1QfxjNfta5IMFe3O9ZEPw=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "c5f08b62ed75415439d48152c2a784e36909b1bc",
+        "rev": "d2b1213bf5ec5e62d96b003ab4b5cbc42abfc0d0",
         "type": "github"
       },
       "original": {
@@ -471,11 +475,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1754847726,
-        "narHash": "sha256-2vX8QjO5lRsDbNYvN9hVHXLU6oMl+V/PsmIiJREG4rE=",
+        "lastModified": 1762938485,
+        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
         "owner": "numtide",
         "repo": "treefmt-nix",
-        "rev": "7d81f6fb2e19bf84f1c65135d1060d829fae2408",
+        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
         "type": "github"
       },
       "original": {
diff --git a/tools/nix/flake.nix b/tools/nix/flake.nix
index 558c3a1..19d19ef 100644
--- a/tools/nix/flake.nix
+++ b/tools/nix/flake.nix
@@ -65,12 +65,12 @@
     # The devenv module to create good development shells.
     # The `nixpkgs-devenv` must aligned with the pinned version.
     devenv = {
-      url = "github:cachix/devenv?ref=v1.8.1";
+      url = "github:cachix/devenv?ref=v1.11.1";
       inputs.nixpkgs.follows = "nixpkgs-devenv";
     };
     # This is the rolling nixpkgs with what devenv was tested.
     nixpkgs-devenv = {
-      url = "github:cachix/devenv-nixpkgs?ref=0ceffe312871b443929ff3006960d29b120dc627";
+      url = "github:cachix/devenv-nixpkgs?ref=d1c30452ebecfc55185ae6d1c983c09da0c274ff";
     };
 
     # To build a base image with Nix.