diff --git a/.gitea/workflows/ci-deploy.yml b/.gitea/workflows/ci-deploy.yml
index 4216060..509da45 100644
--- a/.gitea/workflows/ci-deploy.yml
+++ b/.gitea/workflows/ci-deploy.yml
@@ -53,8 +53,20 @@ jobs:
       - name: Build backend tests
         run: dotnet build JobTrackerApi.Tests/JobTrackerApi.Tests.csproj --configuration Release --no-restore
 
+      # Restore and build both pass on this runner, but the test run dies after ~3s -- far too fast to
+      # have executed 306 tests. The suite passes on Windows, in a clean Linux container, under a 1GB
+      # memory cap, and with the SDK installed to a custom dir without DOTNET_ROOT, so the cause is
+      # specific to this runner. This one-test smoke separates "the test host cannot start at all"
+      # from "something in the suite takes the host down"; the log is not readable via the API, so the
+      # step boundary is the signal.
+      - name: Test backend (host smoke)
+        run: dotnet test JobTrackerApi.Tests/JobTrackerApi.Tests.csproj --configuration Release --no-build --filter "FullyQualifiedName~CvBuilderTests.Every_catalog_theme_renders_valid_html"
+
+      # Collection parallelism is disabled here for the same reason the frontend runs --runInBand:
+      # this runner is resource-flaky (documented npm ci SIGSEGV and SDK cache corruption above).
+      # Every one of the 306 tests still runs -- only the concurrency changes.
       - name: Test backend
-        run: dotnet test JobTrackerApi.Tests/JobTrackerApi.Tests.csproj --configuration Release --no-build
+        run: dotnet test JobTrackerApi.Tests/JobTrackerApi.Tests.csproj --configuration Release --no-build -- xUnit.parallelizeTestCollections=false xUnit.maxParallelThreads=1
 
       - name: Install frontend deps
         working-directory: job-tracker-ui