diff --git a/.github/workflows/journeys-collect.yml b/.github/workflows/journeys-collect.yml
index 5502a6b9..355f0867 100644
--- a/.github/workflows/journeys-collect.yml
+++ b/.github/workflows/journeys-collect.yml
@@ -16,6 +16,14 @@ on:
     paths:
       - "deploy/**"
       - ".github/workflows/journeys-collect.yml"
+  # The browser probes install chromium at run time, so they can rot from
+  # upstream drift with no repo change at all — and that rot would then surface
+  # as a red on some unrelated future deploy PR. A weekly run finds it on its
+  # own schedule instead. Per-PR alone was still "proven the day it merged",
+  # only with a longer day.
+  schedule:
+    - cron: "17 6 * * 1"
+  workflow_dispatch:
 
 permissions:
   contents: read
@@ -95,3 +103,74 @@ jobs:
                     f"subset collapsed. Failing the gate.")
               sys.exit(1)
           PY
+
+  # ---------------------------------------------------------------------------
+  # The N group's browser-only probes.
+  #
+  # Four of the twenty-two test ids need no stand: the sink control, the
+  # unpoliced-channel control, and both halves of the script-execution probe
+  # reproduce the isolation primitives standalone. Without this job they only
+  # ever ran by hand, and "proven by running probes" decays to "proven the day
+  # it merged".
+  #
+  # This job covers 4 of 22 — the controls and the script-execution primitive.
+  # It is NOT "the N group covered": the other eighteen need a live pane, portal
+  # and render frame, and they are the tier-2 gate against a real stand.
+  #
+  # OCU_BROWSER_E2E is SET here on purpose: with the gate set and no chromium,
+  # `_require_browser` FAILS rather than skipping, so a broken install cannot
+  # read as a pass.
+  # ---------------------------------------------------------------------------
+  frame-egress-probes:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b # v5.3.0
+        with:
+          python-version: "3.12"
+      - name: Install playwright + chromium
+        # Pinned, like the sibling job's requirements file. A floating
+        # playwright changes what the probe MEANS between runs: the same green
+        # would be measuring a different browser contract each week.
+        run: |
+          python -m pip install --upgrade pip
+          # The journeys conftest imports yaml, so the suite's own requirements
+          # come first — measured: without them the job dies at collection with
+          # ModuleNotFoundError before a single probe runs. My local venv had it
+          # already, which is exactly why the CI run is the one that counts.
+          python -m pip install -r deploy/tests/journeys/requirements.txt
+          python -m pip install "playwright==1.62.0" "pytest==9.1.1"
+          python -m playwright install --with-deps chromium
+      - name: Run the standalone probes
+        env:
+          OCU_BROWSER_E2E: "1"
+        # -k selects the four that need no stand and DESELECTS the other
+        # eighteen. Deselected is not skipped: they never run, never reach -rs,
+        # and never enter the junit — measured, `-rs` reports zero SKIPPED lines
+        # here. Their absence is detectable only through the equality guard
+        # below, which is why that guard is the load-bearing half of this job.
+        run: |
+          pytest -rs -o xfail_strict=true --strict-markers \
+            --junit-xml=n-group-report.xml \
+            -k "n0 or n2 or n4" \
+            deploy/tests/journeys/test_n_frame_egress.py
+      - name: Guard against a vacuous browser-probe pass
+        # Same failure this file already guards for the journeys: a suite where
+        # everything skipped renders green. Four is the measured count, and it
+        # is an equality rather than a floor -- a probe silently dropping out of
+        # the selection is the regression, and a floor would hide it.
+        run: |
+          python3 - <<'PY'
+          import sys, xml.etree.ElementTree as ET
+          root = ET.parse("n-group-report.xml").getroot()
+          suites = root.findall("testsuite") or [root]
+          total = sum(int(s.get("tests", 0)) for s in suites)
+          skipped = sum(int(s.get("skips", s.get("skipped", 0))) for s in suites)
+          executed = total - skipped
+          print(f"browser probes: total={total} skipped={skipped} executed={executed}")
+          if executed != 4:
+              print(f"EXPECTED 4 executed browser probes, got {executed}. Either a "
+                    f"probe stopped running or one was added without updating this "
+                    f"count. Both need a look.")
+              sys.exit(1)
+          PY