diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
index 34ac2b6..2b90211 100644
--- a/.gitea/workflows/release.yml
+++ b/.gitea/workflows/release.yml
@@ -51,18 +51,22 @@
 #
 # Prerequisites (Settings → Actions → Secrets on RunicGateway/servuo-plugins):
 #   REGISTRY_TOKEN  — Gitea access token with `write:repository`, to push the
-#                     tag and create the release.
+#                     tag and create the release. The final step also dispatches
+#                     RunicGateway/installer's bundle workflow, so the token
+#                     ideally has write there too — a nicety, not a requirement:
+#                     without it the step warns and that repo's nightly cron
+#                     picks the release up instead.
 #   REGISTRY_USER   — the Gitea username that token belongs to.
 #
 # These are checked by an explicit preflight step rather than left to fail
 # wherever they happen to be used first — see the comment on that step for why
 # an absent token does NOT simply fail the tag push.
 #
-# TODO (Phase 0 item 3): once the installer repo's bundle workflow exists, append
-# a final step here that POSTs to its workflow-dispatch endpoint, so a new
-# overlay release recomposes the bundle immediately instead of waiting for the
-# nightly cron (PLAN.md §7.2). Deliberately absent until there is something to
-# dispatch — a step that 404s every release is worse than no step.
+# The final step POSTs to the installer repo's bundle workflow, so a new overlay
+# release recomposes the compat matrix immediately instead of waiting for that
+# repo's nightly cron (PLAN.md §7.2). It was deliberately absent until Phase 0
+# item 3 landed something to dispatch — a step that 404s on every release is
+# worse than no step.
 
 name: Release overlay
 
@@ -84,6 +88,9 @@ env:
   # house style set by link (pre-1.0; the release version is independent of the
   # protocol version, which lives in overlay.toml).
   SEED_VERSION: "0.1.0"
+  # Notified after a release so the installer's compat matrix picks up this
+  # overlay immediately rather than at its next nightly run (PLAN.md §7.2).
+  INSTALLER_REPO: RunicGateway/installer
 
 jobs:
   release:
@@ -425,3 +432,45 @@ jobs:
               -F "attachment=@dist/${f}" >/dev/null
             echo "  uploaded ${f}"
           done
+
+      # ── Recompose the installer's bundle manifest ────────────────────────
+      # The installer does not resolve "latest" at run time — it deploys the
+      # exact overlay named by a published bundle (docs/installer/PLAN.md §7.1).
+      # An overlay release that nobody recomposes around is therefore a release
+      # no operator will ever be offered. This tells the installer repo to
+      # rebuild that manifest now rather than leaving the new version invisible
+      # until its nightly cron.
+      #
+      # That job re-reads this tarball's manifest.json and checks its declared
+      # `protocol` against the sidecar's PROTOCOL_VERSION before publishing
+      # anything (PLAN.md §7.1, gate 1) — which is the check this repo cannot
+      # perform for itself, since the C# plugin announces no version on the wire.
+      #
+      # DISPATCH, DON'T WAIT (PLAN.md §7.3). Gitea's workflow-dispatch endpoint
+      # returns no run handle, so there is nothing to poll: a waiting step would
+      # have to guess which run is its own and hold a runner idle to do it.
+      #
+      # A failure here is a WARNING, never a failure of this job. The release is
+      # already published and correct by this point, and failing the run would
+      # misreport that. The installer's nightly cron recomposes from whatever the
+      # latest releases actually are, so a dropped dispatch costs latency, not
+      # correctness.
+      - name: Ask the installer repo to recompose its bundle
+        if: ${{ steps.plan.outputs.release == 'true' }}
+        env:
+          REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
+        run: |
+          set -euo pipefail
+          CI_TOKEN="$(printf '%s' "${REGISTRY_TOKEN}" | tr -d '\r\n')"
+          HTTP="$(curl -s -o /dev/null -w '%{http_code}' -X POST \
+            -H "Authorization: token ${CI_TOKEN}" \
+            -H "Content-Type: application/json" \
+            -d '{"ref":"main"}' \
+            "https://${GITEA_HOST}/api/v1/repos/${INSTALLER_REPO}/actions/workflows/bundle.yml/dispatches" || echo 000)"
+          case "$HTTP" in
+            20*) echo "Dispatched ${INSTALLER_REPO} bundle.yml (HTTP ${HTTP}) — not waiting for it." ;;
+            403|404)
+              echo "::warning::Could not dispatch ${INSTALLER_REPO} bundle.yml (HTTP ${HTTP}). REGISTRY_TOKEN likely lacks write:repository on that repo. Release ${{ steps.plan.outputs.tag }} is published and fine; its bundle will be composed by the installer's nightly cron instead." ;;
+            *)
+              echo "::warning::Dispatching ${INSTALLER_REPO} bundle.yml returned HTTP ${HTTP}. Release ${{ steps.plan.outputs.tag }} is published and fine; the nightly cron will recompose the bundle." ;;
+          esac