diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 07e44d52..50dccd4a 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -222,7 +222,8 @@ jobs:
         run: npx react-native bundle --entry-file index.js --platform macos --dev false --minify false --bundle-output dist/main.macos.jsbundle --assets-dest dist/res
         working-directory: apps/macos-test-app
       - name: Build test app
-        run: xcodebuild archive -workspace MacOSTestApp.xcworkspace -configuration Release -scheme MacOSTestApp-macOS -destination generic/platform="macOS" -archivePath ./build/macos-test-app.xcarchive | xcbeautify
+        # pipefail so an xcodebuild failure is not masked by xcbeautify's exit code
+        run: set -o pipefail && xcodebuild archive -workspace MacOSTestApp.xcworkspace -configuration Release -scheme MacOSTestApp-macOS -destination generic/platform="macOS" -archivePath ./build/macos-test-app.xcarchive | xcbeautify
         working-directory: apps/macos-test-app/macos
       - name: Run test app
         run: npx mocha-remote --exit-on-error -- macos/build/macos-test-app.xcarchive/Products/Applications/MacOSTestApp.app/Contents/MacOS/MacOSTestApp
diff --git a/apps/test-app/metro.config.js b/apps/test-app/metro.config.js
index 395431b6..009b8d4f 100644
--- a/apps/test-app/metro.config.js
+++ b/apps/test-app/metro.config.js
@@ -17,6 +17,23 @@ if (config.projectRoot.endsWith("macos-test-app")) {
   // duplicate react-native version and pollution of the package lock.
   const path = require("node:path");
   config.watchFolders.push(path.resolve(__dirname, "../.."));
+
+  // The babel plugin rewrites `require("something.node")` inside the workspace
+  // packages (e.g. packages/ferric-example/ferric_example.js) into
+  // `require("react-native-node-api").requireNodeAddon(...)`. Those files live
+  // outside this app, so Metro resolves the bare `react-native-node-api` (and
+  // sibling workspace packages) by walking up from the package directory. Under
+  // npm's hoisted workspaces that specifier happens to sit in the repo-root
+  // node_modules, but under pnpm's isolated node_modules it does not, so the
+  // rewritten require fails to resolve. This app installs the workspace packages
+  // into its own node_modules (via `npm install` of `file:` deps), so add that
+  // directory as a global module-resolution path to make resolution independent
+  // of the root package manager's hoisting layout.
+  config.resolver = config.resolver || {};
+  config.resolver.nodeModulesPaths = [
+    ...(config.resolver.nodeModulesPaths || []),
+    path.resolve(__dirname, "node_modules"),
+  ];
 }
 
 module.exports = config;
diff --git a/scripts/init-macos-test-app.ts b/scripts/init-macos-test-app.ts
index 84708634..fab1cbfe 100644
--- a/scripts/init-macos-test-app.ts
+++ b/scripts/init-macos-test-app.ts
@@ -88,6 +88,11 @@ async function patchPackageJson() {
 
   const transferredDependencies = new Set([
     "@rnx-kit/metro-config",
+    // `mocha-remote-server` (pulled in by `mocha-remote-cli`) requires `mocha` at
+    // runtime. It resolves fine in the workspace apps via hoisting, but this app
+    // is installed standalone, so `mocha` must be an explicit dependency here or
+    // the "Run test app" step fails with "Cannot find module 'mocha'".
+    "mocha",
     "mocha-remote-cli",
     "mocha-remote-react-native",
   ]);
@@ -169,7 +174,25 @@ async function patchPodfile() {
     ],
     [
       "react_native_post_install(installer)",
-      "react_native_post_install(installer, '../node_modules/react-native-macos')",
+      `react_native_post_install(installer, '../node_modules/react-native-macos')
+
+    # Xcode 26.4 ships Apple clang 21, which enforces C++20 'consteval' more
+    # strictly and rejects fmt 11.0.2's FMT_STRING() usages with "call to
+    # consteval function ... is not a constant expression" (in fmt itself, Yoga
+    # and React-logger). React Native 0.81 bundles fmt 11.0.2 and the upstream
+    # fix (fmt 12.1.0) only reached React Native >= 0.83.9, so force fmt's
+    # compile-time (consteval) format-string checking off — it falls back to
+    # runtime validation, which compiles cleanly. Patch the vendored fmt headers
+    # directly (setting FMT_USE_CONSTEVAL to 0) rather than via a build-settings
+    # define, because the define does not reliably reach every fmt-consuming
+    # translation unit.
+    fmt_root = File.join(installer.sandbox.root.to_s, 'fmt')
+    Dir.glob(File.join(fmt_root, '**', '*.h')).each do |header|
+      contents = File.read(header)
+      next unless contents.include?('FMT_USE_CONSTEVAL')
+      patched = contents.gsub(/#\\s*define\\s+FMT_USE_CONSTEVAL\\s+1\\b/, '#define FMT_USE_CONSTEVAL 0')
+      File.write(header, patched) if patched != contents
+    end`,
     ],
   ];