diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
index 072b06f..480bc70 100644
--- a/.gitea/workflows/ci.yml
+++ b/.gitea/workflows/ci.yml
@@ -10,6 +10,10 @@ name: ci
 
 on:
   push:
+    branches-ignore:
+      # TEMPORARY (TST-25 Check 6 probe branch) — keeps the expensive portable/java/windows-x86
+      # jobs off the shared runner while `tst25-check6-probe.yml` exercises the failure path.
+      - 'test/tst25-check6-nightly-issue'
   pull_request:
   schedule:
     # 06:00 UTC nightly: the `nightly-windev` job re-runs the x86 Worker build + full Worker.Tests on
diff --git a/.gitea/workflows/tst25-check6-probe.yml b/.gitea/workflows/tst25-check6-probe.yml
new file mode 100644
index 0000000..8a539f0
--- /dev/null
+++ b/.gitea/workflows/tst25-check6-probe.yml
@@ -0,0 +1,31 @@
+# TEMPORARY — TST-25 acceptance Check 6 probe. Lives only on `test/tst25-check6-nightly-issue`
+# and is deleted with that branch. It reproduces the `nightly-windev` job's shape (a failing main
+# step followed by the `if: failure()` Gitea-issue step) with the live-MXAccess run replaced by a
+# forced failure, so the issue-creation path can be exercised without burning a windev live run.
+name: tst25-check6-probe
+
+on:
+  push:
+    branches:
+      - 'test/tst25-check6-nightly-issue'
+
+jobs:
+  nightly-windev-probe:
+    runs-on: ubuntu-latest
+    env:
+      # `github.server_url` is the runner-internal `http://gitea:3000` — correct for the API call
+      # below (the job container resolves gitea only on the docker network) but useless as a link
+      # a human can click. Browser-facing URLs in the issue body use the public origin instead.
+      PUBLIC_SERVER_URL: https://gitea.dohertylan.com
+    steps:
+      - uses: actions/checkout@v4
+      - name: Forced failure standing in for the live-MXAccess run
+        run: exit 1
+      - name: Report a red nightly as a Gitea issue
+        if: failure()
+        run: |
+          curl -sSf -X POST \
+            -H "Authorization: token ${{ github.token }}" \
+            -H "Content-Type: application/json" \
+            "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/issues" \
+            -d "{\"title\":\"[CHECK6 PROBE] nightly-windev failed on ${{ github.sha }}\",\"body\":\"The scheduled windev Worker + live-MXAccess run failed: ${PUBLIC_SERVER_URL}/${{ github.repository }}/actions/runs/${{ github.run_id }} . A red nightly may mean the Windows tier is down rather than the change — see docs/GatewayTesting.md (Continuous Integration).\"}"