feat: add node-pty Nix derivation for terminal support

Build node-pty from source using buildNpmPackage so Claude Desktop's
terminal features (Claude Code) work on NixOS. The derivation handles
three issues with the upstream package:

- Strips macOS-only fsevents reference from package-lock.json so
  npm ci doesn't fail on lock/json mismatch
- Runs both tsc (TypeScript to JS) and node-gyp rebuild (native addon)
- Copies build/Release/pty.node into output since npmInstallHook
  doesn't include native addons

Also wires node-pty into claude-desktop.nix via --node-pty-dir flag
and updates the flake overlay to expose it.

Co-Authored-By: Claude <claude@anthropic.com>

build.sh

@@ -17,6 +17,7 @@ cleanup_action='yes'
 perform_cleanup=false
 test_flags_mode=false
 local_exe_path=''
+node_pty_dir=''
 original_user=''
 original_home=''
 project_root=''
@@ -192,7 +193,7 @@ parse_arguments() {
 
 	while (( $# > 0 )); do
 		case "$1" in
-			-b|--build|-c|--clean|-e|--exe|-r|--release-tag|-s|--source-dir)
+			-b|--build|-c|--clean|-e|--exe|-r|--release-tag|-s|--source-dir|--node-pty-dir)
 				if [[ -z ${2:-} || $2 == -* ]]; then
 					echo "Error: Argument for $1 is missing" >&2
 					exit 1
@@ -203,6 +204,7 @@ parse_arguments() {
 					-e|--exe) local_exe_path="$2" ;;
 					-r|--release-tag) release_tag="$2" ;;
 					-s|--source-dir) source_dir="$2" ;;
+					--node-pty-dir) node_pty_dir="$2" ;;
 				esac
 				shift 2
 				;;
@@ -217,6 +219,7 @@ parse_arguments() {
 				echo '  --clean: Specify whether to clean intermediate build files (yes or no). Default: yes'
 				echo '  --exe:   Use a local Claude installer exe instead of downloading'
 				echo '  --source-dir: Path to repo root for scripts/ and assets (default: project root)'
+				echo '  --node-pty-dir: Path to pre-built node-pty package (skips npm install)'
 				echo '  --release-tag: Release tag (e.g., v1.3.2+claude1.1.799) to append wrapper version to package'
 				echo '  --test-flags: Parse flags, print results, and exit without building.'
 				exit 0

flake.nix

@@ -11,7 +11,10 @@
       systems = [ "x86_64-linux" "aarch64-linux" ];
 
       perSystem = { pkgs, ... }: let
-        claude-desktop = pkgs.callPackage ./nix/claude-desktop.nix { };
+        node-pty = pkgs.callPackage ./nix/node-pty.nix { };
+        claude-desktop = pkgs.callPackage ./nix/claude-desktop.nix {
+          inherit node-pty;
+        };
       in {
         packages = {
           inherit claude-desktop;
@@ -23,8 +26,12 @@
       };
 
       flake = {
-        overlays.default = final: prev: {
-          claude-desktop = final.callPackage ./nix/claude-desktop.nix { };
+        overlays.default = final: prev: let 
+          node-pty = final.callPackage ./nix/node-pty.nix { };
+        in  {
+          claude-desktop = final.callPackage ./nix/claude-desktop.nix {
+            inherit node-pty;
+          };
           claude-desktop-fhs = final.callPackage ./nix/fhs.nix {
             claude-desktop = final.claude-desktop;
           };

nix/claude-desktop.nix

@@ -13,6 +13,7 @@
   python3,
   bash,
   getent,
+  node-pty,
 }:
 let
   pname = "claude-desktop";
@@ -78,6 +79,7 @@ stdenvNoCC.mkDerivation {
     bash ${sourceRoot}/build.sh \
       --exe "$(pwd)/Claude-Setup.exe" \
       --source-dir "${sourceRoot}" \
+      --node-pty-dir "${node-pty}/lib/node_modules/node-pty" \
       --build nix \
       --clean no
 
@@ -92,9 +94,6 @@ stdenvNoCC.mkDerivation {
     cp build/electron-app/app.asar $out/lib/claude-desktop/resources/
     cp -r build/electron-app/app.asar.unpacked $out/lib/claude-desktop/resources/
 
-    # TODO: node-pty is not in nixpkgs; terminal features (Claude Code)
-    # require it. A future improvement could build it with buildNpmPackage.
-
     # Install icons
     for size in 16 24 32 48 64 256; do
       icon_dir=$out/share/icons/hicolor/"$size"x"$size"/apps

nix/node-pty.nix

@@ -0,0 +1,51 @@
+{
+  lib,
+  buildNpmPackage,
+  fetchFromGitHub,
+  python3,
+  node-gyp,
+}:
+buildNpmPackage rec {
+  pname = "node-pty";
+  version = "1.1.0";
+
+  src = fetchFromGitHub {
+    owner = "microsoft";
+    repo = "node-pty";
+    rev = "v${version}";
+    hash = "sha256-R0QxTw3tNJvW4aEi+GOF0iZhGgI42HTYJih90CdF18I=";
+  };
+
+  npmDepsHash = "sha256-HRv/4NO7CHkPs7ld8lx61n2cty0EhmWVrpH/1Vqh+Nk=";
+
+  # node-gyp needs python3 for native compilation
+  nativeBuildInputs = [ python3 node-gyp ];
+
+  # chokidar (dev dep) has an optional dep on fsevents (macOS-only).
+  # The Nix npm deps fetcher excludes it, so npm ci sees a lock/json
+  # mismatch. Strip the reference from the lock file to fix the sync.
+  postPatch = ''
+    sed -i '/"fsevents"/d' package-lock.json
+  '';
+
+  # Default npmBuildHook only runs "npm run build" (tsc), but we also
+  # need the native addon. Run both explicitly.
+  buildPhase = ''
+    runHook preBuild
+    npm run build
+    node-gyp rebuild
+    runHook postBuild
+  '';
+
+  # npmInstallHook doesn't copy the native addon — do it ourselves
+  postInstall = ''
+    cp -r build $out/lib/node_modules/node-pty/
+  '';
+
+  meta = with lib; {
+    description = "Fork pseudoterminals in Node.JS";
+    homepage = "https://github.com/microsoft/node-pty";
+    license = licenses.mit;
+    platforms = platforms.linux;
+  };
+}