diff --git a/scripts/test-parallel.mjs b/scripts/test-parallel.mjs
index fc5081d19f..e13f507375 100644
--- a/scripts/test-parallel.mjs
+++ b/scripts/test-parallel.mjs
@@ -29,6 +29,8 @@ const unitIsolatedFilesRaw = [
   "src/browser/server.auth-token-gates-http.test.ts",
   "src/browser/server-context.remote-tab-ops.test.ts",
   "src/browser/server-context.ensure-tab-available.prefers-last-target.test.ts",
+  // Keep this high-variance heavy file off the unit-fast critical path.
+  "src/auto-reply/reply.block-streaming.test.ts",
   // Uses process-level unhandledRejection listeners; keep it off vmForks to avoid cross-file leakage.
   "src/imessage/monitor.shutdown.unhandled-rejection.test.ts",
 ];