fix(pi): use node backend for wsl

There is a segfault when using bun backend on wsl.

Author: EdenEast

flake.lock

@@ -18,7 +18,10 @@
           zsh.enable = true;
 
           claude.enable = true;
-          pi.enable = true;
+          pi = {
+            enable = true;
+            useBun = false;
+          };
           neovim.useNightly = true;
 
           git = {

hosts/rize/home.nix

@@ -4,15 +4,35 @@
   inputs,
   pkgs,
   ...
-}: {
+}: let
+  cfg = config.my.home.programs.pi;
+in {
   options.my.home.programs.pi = {
     enable = lib.mkEnableOption "pi coding agent harness";
+    useBun = lib.mkOption {
+      description = "Build with Bun instead of Node";
+      type = lib.types.bool;
+      default = true;
+    };
   };
 
-  config = lib.mkIf config.my.home.programs.pi.enable {
+  config = lib.mkIf cfg.enable {
     home = {
       packages = [
-        inputs.llm-agents.packages.${pkgs.stdenv.hostPlatform.system}.pi
+        ((pkgs.callPackage (inputs.llm-agents + /packages/pi/package.nix) {
+            inherit (cfg) useBun;
+            # llm-agents.nix defines this helper in its package scope, but it is
+            # not exported. The Node build does not need the HOME workaround for
+            # its version check, so an inert input is enough here.
+            versionCheckHomeHook = pkgs.emptyFile;
+          })
+          .overrideAttrs (_old:
+            lib.optionalAttrs cfg.useBun {
+              # Pi 0.82.1's Bun binary no longer prints the package version from
+              # `--version` or `--help`, so upstream's versionCheckHook fails
+              # after an otherwise successful build.
+              doInstallCheck = false;
+            }))
       ];
 
       # sessionVariables = {