diff --git a/.github/workflows/e2e-derived-data-seed.yml b/.github/workflows/e2e-derived-data-seed.yml
new file mode 100644
index 000000000000..aae0fbe8ed68
--- /dev/null
+++ b/.github/workflows/e2e-derived-data-seed.yml
@@ -0,0 +1,56 @@
+name: E2E DerivedData seed
+
+# test-e2e.yml builds start from the DerivedData that a main-contained dispatch
+# of that workflow published (#14016), so a test-only change recompiles only
+# the tests. Focused dispatches test pull request revisions, which never
+# publish, and nothing dispatches main on a schedule: seeds so far came from
+# hand dispatches, and each artifact expires after 3 days.
+#
+# Every 6 hours this dispatches test-e2e.yml on main's HEAD with one fast suite,
+# unless that SHA already has a seed dispatch. It dispatches instead of calling
+# so the run keeps the identity e2e_warm_derived_data.py trusts (path
+# test-e2e.yml, event workflow_dispatch, branch main).
+on:
+  schedule:
+    - cron: "41 */6 * * *"
+  workflow_dispatch:
+
+permissions: {}
+
+jobs:
+  dispatch:
+    name: Dispatch a main build of test-e2e.yml
+    if: ${{ github.ref == 'refs/heads/main' }}
+    runs-on: ${{ vars.LINUX_RUNNER || 'blacksmith-4vcpu-ubuntu-2404' }}
+    timeout-minutes: 5
+    concurrency:
+      group: e2e-derived-data-seed
+      cancel-in-progress: false
+    permissions:
+      actions: write
+      contents: read
+    steps:
+      - name: Dispatch unless main's HEAD already has a seed
+        env:
+          GH_TOKEN: ${{ github.token }}
+          # 36 ms on CI: the seed exists for its build, not its test.
+          SEED_FILTER: cmuxTests/CmuxPopoverGroupTests
+        run: |
+          set -euo pipefail
+          head_sha="$(gh api "repos/$GITHUB_REPOSITORY/branches/main" --jq '.commit.sha')"
+          # test-e2e.yml's run name carries the tested ref and the dispatch id.
+          # A run that built but failed its test still published, so only runs
+          # that never finished count as missing.
+          existing="$(gh run list --repo "$GITHUB_REPOSITORY" --workflow test-e2e.yml \
+            --branch main --event workflow_dispatch --limit 300 --json displayTitle,conclusion \
+            --jq "[.[] | select((.displayTitle | contains(\"@ $head_sha\")) and (.displayTitle | contains(\"[e2e-derived-data-seed-\")) and (.conclusion != \"cancelled\" and .conclusion != \"timed_out\" and .conclusion != \"startup_failure\"))] | length")"
+          if [ "$existing" != "0" ]; then
+            echo "main's HEAD $head_sha already has a seed dispatch." >> "$GITHUB_STEP_SUMMARY"
+            exit 0
+          fi
+          gh workflow run test-e2e.yml --repo "$GITHUB_REPOSITORY" --ref main \
+            -f ref="$head_sha" \
+            -f test_filter="$SEED_FILTER" \
+            -f dispatch_id="e2e-derived-data-seed-$GITHUB_RUN_ID" \
+            -f record_video=false
+          echo "Dispatched a DerivedData seed build of $head_sha." >> "$GITHUB_STEP_SUMMARY"
diff --git a/.github/workflows/test-e2e.yml b/.github/workflows/test-e2e.yml
index d31e0501310e..47285584a906 100644
--- a/.github/workflows/test-e2e.yml
+++ b/.github/workflows/test-e2e.yml
@@ -304,8 +304,11 @@ jobs:
         id: product-key
         run: python3 scripts/ci/reuse_app_host_products.py key "$CMUX_DERIVED_DATA_PATH"
 
+      # e2e-derived-data-seed.yml dispatches exist to publish DerivedData,
+      # which only a compile produces, so they never adopt a product.
       - name: Reuse a compiled product instead of building one
         id: reuse
+        if: ${{ !startsWith(inputs.dispatch_id, 'e2e-derived-data-seed-') }}
         continue-on-error: true
         env:
           GH_TOKEN: ${{ github.token }}