diff --git a/hosts/nixos/thinkpad/disk-config.nix b/hosts/nixos/thinkpad/disk-config.nix
index 22ae116..e4933ee 100644
--- a/hosts/nixos/thinkpad/disk-config.nix
+++ b/hosts/nixos/thinkpad/disk-config.nix
@@ -1,6 +1,3 @@
-# Disko configuration for ThinkPad P14s Gen 2
-# Reflects the actual installed system configuration
-# NOTE: This uses UUIDs from the existing installation
 {
   disko.devices = {
     disk = {
@@ -37,4 +34,4 @@
       };
     };
   };
-}
\ No newline at end of file
+}
diff --git a/modules/borg/client.nix b/modules/borg/client.nix
index c1d5bc0..caa3046 100644
--- a/modules/borg/client.nix
+++ b/modules/borg/client.nix
@@ -1,3 +1,6 @@
+# NOTE: Passphrase file at: `/etc/borg-passphrase` with mode 600
+# content: `BORG_PASSPHRASE=your-passphrase`
+
 { config, lib, pkgs, ... }:
 
 with lib;
@@ -5,9 +8,6 @@ with lib;
 let
   cfg = config.services.borg-client-custom;
   sshCommand = "ssh -F /home/yanlin/.ssh/config -o StrictHostKeyChecking=accept-new -o ServerAliveInterval=60 -o ServerAliveCountMax=240";
-  # NOTE: Passphrase file: /etc/borg-passphrase
-  # Should contain: BORG_PASSPHRASE=your-passphrase
-  # Place on host with mode 0600
   passphraseFile = "/etc/borg-passphrase";
   excludePatterns = [
     "*.tmp" "*.temp" "*/.cache/*" "*/.local/share/Trash/*" "*/tmp/*" "*/temp/*"
diff --git a/modules/dufs.nix b/modules/dufs.nix
index d24eb66..3601a09 100644
--- a/modules/dufs.nix
+++ b/modules/dufs.nix
@@ -1,3 +1,6 @@
+# NOTE: Authentication file at: `/etc/dufs-auth` with mode 600
+# content: `username:password`
+
 { config, pkgs, lib, ... }:
 
 let
@@ -36,10 +39,6 @@ in
     # Install dufs package
     environment.systemPackages = [ pkgs.dufs ];
 
-    # Create systemd service
-    # NOTE: Authentication credentials must be manually created in /etc/dufs-auth
-    # The file should contain a single line in format: username:password
-    # Make sure to set permissions: chmod 600 /etc/dufs-auth
     systemd.services.dufs = {
       description = "Dufs WebDAV File Server";
       wantedBy = [ "multi-user.target" ];
diff --git a/modules/gemini-cli.nix b/modules/gemini-cli.nix
index e3a6bc7..dd5bbcf 100644
--- a/modules/gemini-cli.nix
+++ b/modules/gemini-cli.nix
@@ -1,3 +1,6 @@
+# NOTE: API key file at: `~/.gemini/.env` with mode 600
+# content: `GEMINI_API_KEY=your-api-key`
+
 { config, pkgs, lib, ... }:
 
 {
@@ -61,10 +64,4 @@
 
     context."GEMINI" = "";
   };
-
-  # NOTE: API key must be manually created in ~/.gemini/.env
-  # The file should contain:
-  #   GEMINI_API_KEY=your-api-key
-  # Get your API key from https://aistudio.google.com/apikey
-  # Make sure to set permissions: chmod 600 ~/.gemini/.env
 }
diff --git a/modules/samba.nix b/modules/samba.nix
index 97d0947..8145943 100644
--- a/modules/samba.nix
+++ b/modules/samba.nix
@@ -1,3 +1,5 @@
+# NOTE: Samba user password manually set: `sudo smbpasswd -a ${cfg.user}`
+
 { config, pkgs, lib, ... }:
 
 let
@@ -62,9 +64,5 @@ in
       "d ${cfg.sharedPath} 0755 ${cfg.user} users - -"
     ];
 
-    # NOTE: Samba user password must be manually set using:
-    # sudo smbpasswd -a ${cfg.user}
-    # This creates a Samba password for the specified user.
-    # The user must already exist as a Unix user on the system.
   };
 }
diff --git a/modules/tailscale.nix b/modules/tailscale.nix
index 3ba58e4..64e3e51 100644
--- a/modules/tailscale.nix
+++ b/modules/tailscale.nix
@@ -1,3 +1,6 @@
+# NOTE: Auth key file at: `/etc/tailscale/authkey` with mode 600
+# content: `tailscale-api-key`
+
 { config, pkgs, lib, ... }:
 
 with lib;
@@ -8,10 +11,6 @@ let
 in
 
 {
-  # NOTE: Auth key file: /etc/tailscale/authkey
-  # Generate at https://login.tailscale.com/admin/settings/keys
-  # Place on host with mode 0600
-
   options.services.tailscale-custom = {
     exitNode = mkOption {
       type = types.bool;
diff --git a/modules/traefik.nix b/modules/traefik.nix
index 9c0a567..7c470a5 100644
--- a/modules/traefik.nix
+++ b/modules/traefik.nix
@@ -1,3 +1,8 @@
+# NOTE: environment file at: `/etc/traefik-env` with mode 600
+# content (for Cloudflare API):
+#   CF_API_EMAIL=your-email@example.com
+#   CF_DNS_API_TOKEN=your-cloudflare-api-token
+
 { config, pkgs, lib, ... }:
 
 {
@@ -79,10 +84,4 @@
     # Mount Docker/Podman socket for service discovery
     BindPaths = [ "/run/podman/podman.sock:/var/run/docker.sock" ];
   };
-
-  # NOTE: Cloudflare credentials must be manually created in /etc/traefik-env
-  # The file should contain:
-  #   CF_API_EMAIL=your-email@example.com
-  #   CF_DNS_API_TOKEN=your-cloudflare-api-token
-  # Make sure to set permissions: chmod 600 /etc/traefik-env
 }
diff --git a/modules/wireguard.nix b/modules/wireguard.nix
index 151c15b..0951726 100644
--- a/modules/wireguard.nix
+++ b/modules/wireguard.nix
@@ -1,3 +1,6 @@
+# NOTE: Private key file at: `/etc/wireguard/private.key` with mode 600
+# Generate with: `wg genkey > /etc/wireguard/private.key`
+
 { config, pkgs, lib, ... }:
 
 with lib;
@@ -27,9 +30,6 @@ in
       description = "UDP port to listen on (server mode only)";
     };
 
-    # NOTE: Private key file: /etc/wireguard/private.key
-    # Generate with: wg genkey > /etc/wireguard/private.key
-    # Place on host with mode 0600 (auto-generated if missing)
     privateKeyFile = mkOption {
       type = types.str;
       default = "/etc/wireguard/private.key";
diff --git a/modules/yt-dlp.nix b/modules/yt-dlp.nix
index 125673d..8d44db1 100644
--- a/modules/yt-dlp.nix
+++ b/modules/yt-dlp.nix
@@ -1,3 +1,7 @@
+# NOTE: Cookie files at:
+#   ~/.config/yt-dlp/cookies-youtube.txt
+#   ~/.config/yt-dlp/cookies-bilibili.txt
+
 { config, pkgs, lib, ... }:
 
 with lib;
@@ -36,10 +40,6 @@ in
       python312Packages.bgutil-ytdlp-pot-provider  # PO token provider for YouTube
     ];
 
-    # NOTE: Cookie files must be manually placed at:
-    #   ~/.config/yt-dlp/cookies-youtube.txt
-    #   ~/.config/yt-dlp/cookies-bilibili.txt
-
     # Create yt-dlp configuration file
     home.file.".config/yt-dlp/config".text = ''
       # Quality settings