diff --git a/apps/console-lab/playwright.config.ts b/apps/console-lab/playwright.config.ts
index 6c27ea7..28e647a 100644
--- a/apps/console-lab/playwright.config.ts
+++ b/apps/console-lab/playwright.config.ts
@@ -5,6 +5,16 @@ export default defineConfig({
   outputDir: "../../test-results/console-lab",
   fullyParallel: false,
   retries: 0,
+  // One worker, deliberately. `fullyParallel: false` only serializes tests
+  // within a file; Playwright still runs files concurrently, and the worker
+  // count then varies with the host's core count. This suite measures real
+  // layout geometry and drives timing-sensitive launcher transitions, so
+  // concurrent load makes it flaky in a way that depends on the machine: a
+  // three-worker Linux run and a two-worker CI run each failed a different
+  // test that passed on a repeat of the identical commit. With `retries: 0`
+  // any such flake fails the whole run, so determinism is worth the wall
+  // clock. Raise this only alongside evidence that the suite is race-free.
+  workers: 1,
   reporter: "line",
   use: {
     baseURL: "http://127.0.0.1:4173",