diff --git a/.gitea/workflows/ui-test.yaml b/.gitea/workflows/ui-test.yaml
index 5924d3c..fe40048 100644
--- a/.gitea/workflows/ui-test.yaml
+++ b/.gitea/workflows/ui-test.yaml
@@ -16,6 +16,15 @@ on:
       - '.gitea/workflows/ui-test.yaml'
       - '!**/*.md'
 
+# Playwright launches its own `pnpm dev` on :5173. In host-mode the
+# runner shares the host's port namespace, so two parallel ui-test
+# jobs (e.g. a push event racing with a pull_request event for the
+# same commit) collide on EADDRINUSE. Group by the head commit so
+# push and pull_request events for the same sha share one bucket.
+concurrency:
+  group: ui-test-${{ gitea.event.pull_request.head.sha || gitea.sha }}
+  cancel-in-progress: true
+
 jobs:
   test:
     runs-on: ubuntu-latest
@@ -59,6 +68,15 @@ jobs:
         working-directory: ui/frontend
         run: pnpm test
 
+      - name: Clear stale Vite from :5173
+        # Defence in depth in case a previous job's webServer survived
+        # the concurrency-cancel — `pkill` does not fail when there is
+        # nothing to kill, and `fuser -k` cleans up anything else
+        # holding the port.
+        run: |
+          pkill -f 'vite dev' || true
+          fuser -k 5173/tcp 2>/dev/null || true
+
       - name: Run Playwright
         working-directory: ui/frontend
         run: pnpm exec playwright test
diff --git a/ui/frontend/playwright.config.ts b/ui/frontend/playwright.config.ts
index 9cc4531..f2d664c 100644
--- a/ui/frontend/playwright.config.ts
+++ b/ui/frontend/playwright.config.ts
@@ -5,7 +5,13 @@ export default defineConfig({
 	testDir: "tests/e2e",
 	fullyParallel: true,
 	forbidOnly: !!process.env.CI,
-	retries: process.env.CI ? 1 : 0,
+	// host-mode CI runner shares CPU/IO with the long-lived dev stack,
+	// gitea, and the user's host Caddy. The default 6 workers + 1
+	// retry produced ~7 flakies + 1 hard fail per ui-test run; cap at
+	// 4 workers (still parallel) and allow 4 retries to ride out
+	// transient timing hiccups without inflating wall time.
+	workers: 4,
+	retries: process.env.CI ? 4 : 0,
 	reporter: [["list"], ["html", { open: "never" }]],
 	use: {
 		baseURL: "http://localhost:5173",