diff --git a/src/buildContents.test.ts b/src/buildContents.test.ts
index 2ce3a53..b59cd6e 100644
--- a/src/buildContents.test.ts
+++ b/src/buildContents.test.ts
@@ -9,7 +9,8 @@ import { describe, expect, it } from "vitest";
 const repoRoot = resolve(dirname(fileURLToPath(import.meta.url)), "..");
 
 describe("production build contents", () => {
-  it("keeps test-support modules out of the TypeScript build graph", () => {
+  // Constructing the full compiler graph can exceed Vitest's default timeout under parallel-suite CPU contention.
+  it("keeps test-support modules out of the TypeScript build graph", { timeout: 15_000 }, () => {
     const buildConfig = readBuildConfig();
     const program = ts.createProgram({ rootNames: buildConfig.fileNames, options: buildConfig.options });
     const projectSources = program.getSourceFiles()