diff --git a/packages/core-testing/src/setup/node.ts b/packages/core-testing/src/setup/node.ts
index d186513..872a132 100644
--- a/packages/core-testing/src/setup/node.ts
+++ b/packages/core-testing/src/setup/node.ts
@@ -1,5 +1,6 @@
 import "./no-instrumentation";
 
-// Reserved for future global node-env setup. Currently a no-op so that
-// vitest configs may reference @repo/core-testing/setup/node uniformly.
+// Applies the no-instrumentation guard (vi.mock against real Sentry/OTel SDK
+// init) via the import above; otherwise reserved for future global node-env
+// setup so vitest configs may reference @repo/core-testing/setup/node uniformly.
 export {};
diff --git a/packages/core-typescript/vitest.base.jsdom.test.ts b/packages/core-typescript/vitest.base.jsdom.test.ts
index 9f0c54e..9e42802 100644
--- a/packages/core-typescript/vitest.base.jsdom.test.ts
+++ b/packages/core-typescript/vitest.base.jsdom.test.ts
@@ -3,7 +3,8 @@ import { jsdomVitestConfig } from "./vitest.base.jsdom";
 
 // jsdomVitestConfig is built with mergeConfig(nodeVitestConfig, ...).
 // mergeConfig concatenates arrays rather than replacing them, so:
-//   - setupFiles inherits the node setup file (currently a no-op) AND adds the jsdom one
+//   - setupFiles inherits the node setup file (which applies the
+//     no-instrumentation guard) AND adds the jsdom one
 //   - include inherits the node patterns AND adds the tsx-aware patterns (the file globs deduplicate at resolution)
 // We assert the EXACT merged arrays so any future change to setup/node.ts or to include
 // behavior is consciously visible in this test.
@@ -12,7 +13,7 @@ describe("jsdomVitestConfig", () => {
   it("uses jsdom environment", () => {
     expect(jsdomVitestConfig.test?.environment).toBe("jsdom");
   });
-  it("loads both the node setup (no-op) and jsdom setup files", () => {
+  it("loads both the node setup (no-instrumentation guard) and jsdom setup files", () => {
     expect(jsdomVitestConfig.test?.setupFiles).toEqual([
       "@repo/core-testing/setup/node",
       "@repo/core-testing/setup/jsdom",