diff --git a/next.config.mjs b/next.config.mjs
index 5a6d13722e..2f06962ee2 100644
--- a/next.config.mjs
+++ b/next.config.mjs
@@ -113,6 +113,17 @@ const nextConfig = {
     // PR-2 of diegosouzapw/OmniRoute#3932: tree-shake barrel re-exports so
     // route bundles don't pull in 14 locale files, every lucide-react icon,
     // or the full date-fns surface when only one helper is used.
+    //
+    // NOTE: this list must only contain EXTERNAL barrel libraries. Do NOT add
+    // the internal `@omniroute/open-sse` workspace here: optimizePackageImports
+    // makes Next.js resolve every export of the package's barrel at build time,
+    // and open-sse's `index.ts` re-exports the entire streaming engine
+    // (executors/translators/services/handlers/mcp-server — thousands of
+    // modules). Combined with the #3501 god-file splits (which multiplied the
+    // re-export edges), this drove the webpack production pass into a heap
+    // runaway that OOM'd even at a 28 GB --max-old-space-size (RSS pinned at the
+    // ceiling in a GC death-spiral). Removing it keeps the build's heap bounded.
+    // optimizePackageImports is designed for external libs, not workspaces.
     optimizePackageImports: [
       "lobehub/icons",
       "@lobehub/icons",
@@ -122,7 +133,6 @@ const nextConfig = {
       "lodash-es",
       "material-symbols",
       "next-intl",
-      "@omniroute/open-sse",
     ],
   },
   outputFileTracingRoot: projectRoot,
diff --git a/tests/unit/next-config.test.ts b/tests/unit/next-config.test.ts
index 475735d936..4a523e50b2 100644
--- a/tests/unit/next-config.test.ts
+++ b/tests/unit/next-config.test.ts
@@ -232,3 +232,22 @@ test("next-intl webpack hook preserves caller config and filters known extractor
     false
   );
 });
+
+test("optimizePackageImports excludes the internal @omniroute/open-sse workspace (build-OOM guard)", async () => {
+  // Regression guard: adding the internal `@omniroute/open-sse` workspace to
+  // optimizePackageImports makes Next.js resolve its entire barrel at build
+  // time, driving the webpack production pass into a heap runaway that OOM'd
+  // even at 28 GB. optimizePackageImports is for EXTERNAL barrel libs only.
+  const { default: nextConfig } = await loadNextConfig("optimize-pkg-imports");
+  const list = nextConfig.experimental?.optimizePackageImports ?? [];
+
+  assert.ok(Array.isArray(list), "optimizePackageImports should be an array");
+  assert.ok(
+    !list.includes("@omniroute/open-sse"),
+    "do NOT add the internal @omniroute/open-sse workspace to optimizePackageImports — it OOMs the production build"
+  );
+  // The intended external barrel libs must remain optimized.
+  for (const lib of ["lucide-react", "date-fns", "next-intl"]) {
+    assert.ok(list.includes(lib), `expected external barrel lib ${lib} to stay optimized`);
+  }
+});