diff --git a/.agents/backend-signing.md b/.agents/backend-signing.md
index 3abb31d7a..98c32d3e9 100644
--- a/.agents/backend-signing.md
+++ b/.agents/backend-signing.md
@@ -16,8 +16,7 @@ side (`pkg/oci/cosignverify` plus the gallery YAML).
   per-arch manifest before checking signatures.
 - **Storage:** Signatures are written as OCI 1.1 referrers
   (`--registry-referrers-mode=oci-1-1`) in the new Sigstore bundle format
-  (current cosign releases do this by default; no `--new-bundle-format`
-  flag). No `:sha256-<hex>.sig` tag clutter.
+  (`--new-bundle-format`). No `:sha256-<hex>.sig` tag clutter.
 - **Consumer:** `pkg/oci/cosignverify` discovers the bundle via the
   referrers API, hands it to `sigstore-go`, and verifies it against the
   policy declared in the gallery YAML (`Gallery.Verification`).
@@ -34,14 +33,15 @@ to sign. The job needs:
 
 - `permissions: { id-token: write, contents: read }` at the job level so
   the runner can exchange its GitHub OIDC token for a Fulcio cert.
-- `sigstore/cosign-installer@v3` step (current cosign releases already
-  default to the new bundle format).
+- `sigstore/cosign-installer@v3` step (the pinned cosign v2 release needs
+  `--new-bundle-format` explicitly).
 - After each `docker buildx imagetools create`, resolve the resulting
   list digest with `docker buildx imagetools inspect <tag> --format
   '{{.Manifest.Digest}}'` and sign:
 
 ```sh
 cosign sign --yes --recursive \
+  --new-bundle-format \
   --registry-referrers-mode=oci-1-1 \
   "${REGISTRY_REPO}@${DIGEST}"
 ```
@@ -70,7 +70,7 @@ entry (`backend/index.yaml`):
   url: github:mudler/LocalAI/backend/index.yaml@master
   verification:
     issuer: "https://token.actions.githubusercontent.com"
-    identity_regex: "^https://github\\.com/mudler/LocalAI/\\.github/workflows/backend_merge\\.yml@refs/heads/master$"
+    identity_regex: "^https://github\\.com/mudler/LocalAI/\\.github/workflows/backend_merge\\.yml@refs/(heads/master|tags/.+)$"
     # Optional revocation cutoff; advance during incident response.
     # not_before: "2026-06-01T00:00:00Z"
 ```
diff --git a/.github/workflows/backend_merge.yml b/.github/workflows/backend_merge.yml
index 37f606aa9..25fc93c75 100644
--- a/.github/workflows/backend_merge.yml
+++ b/.github/workflows/backend_merge.yml
@@ -71,8 +71,8 @@ jobs:
 
       # cosign signs each pushed manifest list with --recursive so the
       # index and every per-arch entry get an attached Sigstore bundle.
-      # Recent cosign releases always emit the new bundle format, so
-      # there's no extra CLI flag to opt into it.
+      # The pinned cosign v2 release needs --new-bundle-format explicitly;
+      # the verifier only consumes OCI 1.1 Sigstore bundle referrers.
       - name: Install cosign
         if: github.event_name != 'pull_request'
         uses: sigstore/cosign-installer@v3
@@ -159,6 +159,7 @@ jobs:
           # manifest before checking signatures need the per-arch
           # signatures, not just the list-level one.
           cosign sign --yes --recursive \
+            --new-bundle-format \
             --registry-referrers-mode=oci-1-1 \
             "quay.io/go-skynet/local-ai-backends@${digest}"
 
@@ -185,6 +186,7 @@ jobs:
           ' <<< "$DOCKER_METADATA_OUTPUT_JSON")
           digest=$(docker buildx imagetools inspect "$first_tag" --format '{{.Manifest.Digest}}')
           cosign sign --yes --recursive \
+            --new-bundle-format \
             --registry-referrers-mode=oci-1-1 \
             "localai/localai-backends@${digest}"
 
diff --git a/docs/content/features/backends.md b/docs/content/features/backends.md
index 0e7c960a6..5eed109d0 100644
--- a/docs/content/features/backends.md
+++ b/docs/content/features/backends.md
@@ -72,6 +72,44 @@ tags:
   - "text-generation"
 ```
 
+### Verifying OCI Backends
+
+Backend galleries can require keyless Sigstore signatures for every OCI image
+they provide. Add a `verification` policy to the gallery configuration, then
+enable strict integrity mode:
+
+```bash
+export LOCALAI_BACKEND_GALLERIES='[{"name":"localai","url":"github:mudler/LocalAI/backend/index.yaml@master","verification":{"issuer":"https://token.actions.githubusercontent.com","identity_regex":"^https://github\\.com/mudler/LocalAI/\\.github/workflows/backend_merge\\.yml@refs/(heads/master|tags/.+)$"}}]'
+export LOCALAI_REQUIRE_BACKEND_INTEGRITY=1
+local-ai run
+```
+
+The policy pins the Fulcio issuer and the GitHub Actions workflow identity that
+signed the image. The identity expression covers development images produced
+from `master` and release images produced from tags. Use a narrower expression
+if your deployment only accepts one release channel.
+
+Without strict mode, an OCI gallery without a verification policy installs
+with a warning. With strict mode, LocalAI refuses galleries without a policy,
+images without a compatible Sigstore bundle, and signatures that do not match
+the configured identity. Existing images published before bundle signing was
+enabled must be rebuilt or re-signed before strict deployments can install
+them.
+
+An optional `not_before` RFC3339 value revokes signatures logged before that
+time. Advance it after a signing-workflow compromise, then rebuild or re-sign
+the trusted images:
+
+```json
+{
+  "verification": {
+    "issuer": "https://token.actions.githubusercontent.com",
+    "identity_regex": "^https://github\\.com/mudler/LocalAI/\\.github/workflows/backend_merge\\.yml@refs/(heads/master|tags/.+)$",
+    "not_before": "2026-08-05T00:00:00Z"
+  }
+}
+```
+
 ## Pre-installing Backends
 
 You can pre-install backends when starting LocalAI using the `LOCALAI_EXTERNAL_BACKENDS` environment variable:
diff --git a/scripts/build/backend-signing_test.sh b/scripts/build/backend-signing_test.sh
new file mode 100755
index 000000000..0453f4f26
--- /dev/null
+++ b/scripts/build/backend-signing_test.sh
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+WORKFLOW="$(dirname "$(realpath "$0")")/../../.github/workflows/backend_merge.yml"
+
+sign_commands=$(grep -Ec -- '^[[:space:]]+cosign sign([[:space:]]|$)' "$WORKFLOW" || true)
+bundle_flags=$(grep -Ec -- '^[[:space:]]+--new-bundle-format([[:space:]]|$)' "$WORKFLOW" || true)
+if [ "$sign_commands" -ne 2 ] || [ "$bundle_flags" -ne "$sign_commands" ]; then
+  echo "FAIL: every backend signing command must request the new bundle format (commands=$sign_commands flags=$bundle_flags)"
+  exit 1
+fi
+
+echo "PASS: backend signing emits Sigstore bundles for both registries"