feat: add OpenCode v2 package lane

flake.nix

@@ -27,10 +27,12 @@
 
       perSystem = {pkgs, ...}: let
         opencodePackage = pkgs.callPackage ./packages/opencode/package.nix {};
+        opencodeV2Package = pkgs.callPackage ./packages/opencode-v2/package.nix {};
       in {
         packages = {
           default = opencodePackage;
           opencode = opencodePackage;
+          opencode-v2 = opencodeV2Package;
         };
 
         apps = {
@@ -44,6 +46,11 @@
             program = "${opencodePackage}/bin/opencode";
             meta.description = "Run packaged opencode";
           };
+          opencode-v2 = {
+            type = "app";
+            program = "${opencodeV2Package}/bin/opencode";
+            meta.description = "Run packaged opencode v2";
+          };
           update = {
             type = "app";
             program = toString (pkgs.writeShellScript "opencode-flake-update" ''
@@ -92,6 +99,10 @@
             imports = [self.homeManagerModules.default];
             programs.opencode.package = self.packages.${pkgs.stdenv.hostPlatform.system}.opencode;
           };
+          withPackageV2 = {pkgs, ...}: {
+            imports = [self.homeManagerModules.default];
+            programs.opencode.package = self.packages.${pkgs.stdenv.hostPlatform.system}.opencode-v2;
+          };
         };
 
         overlays.default = _final: prev: {

packages/opencode-v2/package.nix

@@ -0,0 +1,59 @@
+# OpenCode v2 terminal client (official Linux x64 npm release).
+#
+# Upstream ships a self-contained Bun-compiled binary, so this is a
+# binary-fetch derivation: autoPatchelf only. The Bun payload must survive
+# ELF fixup intact, hence dontStrip/dontPatchELF. V1 is built from source
+# (packages/opencode); v2 has no equivalent source build here yet.
+{
+  lib,
+  stdenvNoCC,
+  stdenv,
+  fetchurl,
+  autoPatchelfHook,
+  openssl,
+  versionCheckHook,
+  writableTmpDirAsHomeHook,
+}: let
+  version = "2.0.21";
+in
+  stdenvNoCC.mkDerivation {
+    pname = "opencode-v2";
+    inherit version;
+
+    src = fetchurl {
+      url = "https://registry.npmjs.org/@opencode/cli-linux-x64/-/cli-linux-x64-${version}.tgz";
+      hash = "sha512-intPGPRrEoZk+5Qq2dzYcq3Wv07vWvQrv56WieurupI9jGJSEAfT4a9Pi6YMW4tEW6SapAds/95K0egVS2YwiA==";
+    };
+
+    nativeBuildInputs = [autoPatchelfHook];
+    buildInputs = [stdenv.cc.cc.lib openssl];
+
+    dontConfigure = true;
+    dontBuild = true;
+    dontStrip = true;
+    dontPatchELF = true;
+
+    installPhase = ''
+      runHook preInstall
+      install -Dm755 bin/opencode $out/bin/opencode
+      runHook postInstall
+    '';
+
+    nativeInstallCheckInputs = [
+      versionCheckHook
+      # v2 writes logs under $HOME/.local/share; give installCheck a writable HOME.
+      writableTmpDirAsHomeHook
+    ];
+    doInstallCheck = true;
+    versionCheckProgramArg = "--version";
+    versionCheckKeepEnvironment = ["HOME"];
+
+    meta = {
+      description = "AI coding agent built for the terminal (OpenCode v2)";
+      homepage = "https://opencode.ai";
+      license = lib.licenses.mit;
+      sourceProvenance = with lib.sourceTypes; [binaryNativeCode];
+      platforms = ["x86_64-linux"];
+      mainProgram = "opencode";
+    };
+  }