diff --git a/package.json b/package.json
index d517387a..c2ca558d 100644
--- a/package.json
+++ b/package.json
@@ -31,7 +31,7 @@
     "team:prove-launch-matrix": "pnpm exec vitest run --maxWorkers 1 --minWorkers 1 test/main/services/team/TeamAgentLaunchMatrix.safe-e2e.test.ts",
     "team:smoke-changes-real-data": "tsx scripts/team-changes-real-data-smoke.ts",
     "smoke:codex-runtime-install": "tsx scripts/smoke/codex-runtime-install.ts",
-    "prebuild": "tsx scripts/fetch-pricing-data.ts && pnpm --filter agent-teams-controller build && pnpm --filter agent-teams-mcp build",
+    "prebuild": "node ./scripts/ci/verify-radix-presence-patch.mjs && tsx scripts/fetch-pricing-data.ts && pnpm --filter agent-teams-controller build && pnpm --filter agent-teams-mcp build",
     "build": "node --max-old-space-size=8192 ./node_modules/electron-vite/bin/electron-vite.js build",
     "stage-runtime": "node ./scripts/stage-runtime.mjs",
     "clean:runtime": "node ./scripts/stage-runtime.mjs --clean",
diff --git a/scripts/ci/verify-radix-presence-patch.mjs b/scripts/ci/verify-radix-presence-patch.mjs
new file mode 100644
index 00000000..36cf3f21
--- /dev/null
+++ b/scripts/ci/verify-radix-presence-patch.mjs
@@ -0,0 +1,33 @@
+import { createRequire } from 'node:module';
+import { readFileSync } from 'node:fs';
+import { dirname, join } from 'node:path';
+
+const require = createRequire(import.meta.url);
+
+const entrypointPath = require.resolve('@radix-ui/react-presence');
+const packageRoot = dirname(dirname(entrypointPath));
+const filesToCheck = ['dist/index.js', 'dist/index.mjs'];
+
+const requiredMarkers = ['nodeCleanupGenerationRef', 'syncNode(null)'];
+const missing = [];
+
+for (const relativePath of filesToCheck) {
+  const filePath = join(packageRoot, relativePath);
+  const source = readFileSync(filePath, 'utf8');
+  const missingMarkers = requiredMarkers.filter((marker) => !source.includes(marker));
+  if (missingMarkers.length > 0) {
+    missing.push(`${relativePath}: ${missingMarkers.join(', ')}`);
+  }
+}
+
+if (missing.length > 0) {
+  console.error(
+    [
+      '@radix-ui/react-presence is installed without the local React 19 Presence patch.',
+      'Run `pnpm install --force` before building production artifacts.',
+      '',
+      ...missing,
+    ].join('\n')
+  );
+  process.exit(1);
+}