diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index f2a9b6e9a79..6dd4b29e185 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -110,6 +110,8 @@ To install dependencies defined in `package.json` as well as root dependencies,
 corepack pnpm install --frozen-lockfile
 ```
 
+The install also applies `patches/ink+7.0.3.patch` through the root `postinstall` (`patch-package`). `packages/cli` compiles against the `ink` frame-controller types that patch adds, and no published `ink` release exports them, so an install that skipped lifecycle scripts (`--ignore-scripts`, or `ignore-scripts=true` in your npm/pnpm config) leaves the build failing with many `Module 'ink' has no exported member ...` errors. `npm run build` re-applies the patch when it is missing; to apply it by hand, run `npm run postinstall`.
+
 To build the entire project (all packages):
 
 ```bash
diff --git a/scripts/build.js b/scripts/build.js
index 9af62e04ee9..3c06f04cd04 100644
--- a/scripts/build.js
+++ b/scripts/build.js
@@ -33,6 +33,26 @@ if (!existsSync(join(root, 'node_modules'))) {
   });
 }
 
+// The root postinstall applies patches/ink+7.0.3.patch, and packages/cli
+// compiles against ink types only that patch adds: an install that skipped
+// lifecycle scripts fails the build with ~50 errors that all blame ink. The
+// patch creates frame-controller.d.ts, which pristine ink@7.0.3 lacks.
+const inkFrameController = join(
+  root,
+  'node_modules/ink/build/frame-controller.d.ts',
+);
+if (!existsSync(inkFrameController)) {
+  execSync('npm run postinstall', { stdio: 'inherit', cwd: root });
+  if (!existsSync(inkFrameController)) {
+    console.error(
+      'build: patches/ink+7.0.3.patch is not applied to node_modules/ink, so\n' +
+        'packages/cli cannot typecheck against it. Run "npm run postinstall"\n' +
+        'and resolve what patch-package reports.',
+    );
+    process.exit(1);
+  }
+}
+
 // build all workspaces/packages in dependency order
 execSync('npm run generate', { stdio: 'inherit', cwd: root });
 
diff --git a/scripts/tests/package-scripts.test.js b/scripts/tests/package-scripts.test.js
index 30330c7e5b4..ffcbe4c72fa 100644
--- a/scripts/tests/package-scripts.test.js
+++ b/scripts/tests/package-scripts.test.js
@@ -1048,6 +1048,31 @@ describe('package scripts', () => {
     expect(readPackageJson().workspaces).toContain('packages/*');
   });
 
+  it('detects an unapplied ink patch by a file the patch creates', () => {
+    const buildScript = readFileSync(
+      path.join(root, 'scripts/build.js'),
+      'utf8',
+    );
+    const sentinel = buildScript.match(
+      /'node_modules\/ink\/build\/([^']+)'/,
+    )?.[1];
+    expect(sentinel).toBeDefined();
+    expect(buildScript).toContain('npm run postinstall');
+
+    const inkPatch = readdirSync(path.join(root, 'patches')).find((name) =>
+      name.startsWith('ink+'),
+    );
+    expect(inkPatch).toBeDefined();
+    const created = readFileSync(path.join(root, 'patches', inkPatch), 'utf8')
+      .split(/^diff --git /m)
+      .find((file) =>
+        file.startsWith(`a/node_modules/ink/build/${sentinel} b/node_modules/`),
+      );
+    // The sentinel only proves the patch is missing if no published ink ships
+    // it, i.e. the patch must create the file rather than edit an existing one.
+    expect(created).toContain('new file mode');
+  });
+
   it('selects the CLI dependency closure without selecting the same-named root', () => {
     const buildScript = readFileSync(
       path.join(root, 'scripts/build.js'),