diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 64e84af..aae9d32 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,6 +19,16 @@ jobs:
           jq -e '.hooks | keys' hooks/hooks.json >/dev/null
           jq -e '.name and .version' .claude-plugin/plugin.json >/dev/null
           jq -e '.plugins' .claude-plugin/marketplace.json >/dev/null
+          jq -e '.name and .version' .codex-plugin/plugin.json >/dev/null
+          jq -e '.plugins' .agents/plugins/marketplace.json >/dev/null
+      - name: Check plugin version agreement
+        run: |
+          c=$(jq -r .version .claude-plugin/plugin.json)
+          x=$(jq -r .version .codex-plugin/plugin.json)
+          if [ "$c" != "$x" ]; then
+            echo "version drift: .claude-plugin/plugin.json=$c .codex-plugin/plugin.json=$x" >&2
+            exit 1
+          fi
       - name: Run hook tests
         run: sh tests/run.sh
 
diff --git a/.local-ci.json b/.local-ci.json
index 49937bb..732b273 100644
--- a/.local-ci.json
+++ b/.local-ci.json
@@ -2,7 +2,11 @@
   "checks": [
     {
       "label": "manifest validation",
-      "run": "jq -e '.hooks | keys' hooks/hooks.json >/dev/null && jq -e '.name and .version' .claude-plugin/plugin.json >/dev/null && jq -e '.plugins' .claude-plugin/marketplace.json >/dev/null"
+      "run": "jq -e '.hooks | keys' hooks/hooks.json >/dev/null && jq -e '.name and .version' .claude-plugin/plugin.json >/dev/null && jq -e '.plugins' .claude-plugin/marketplace.json >/dev/null && jq -e '.name and .version' .codex-plugin/plugin.json >/dev/null && jq -e '.plugins' .agents/plugins/marketplace.json >/dev/null"
+    },
+    {
+      "label": "plugin version agreement",
+      "run": "set -e; c=$(jq -r .version .claude-plugin/plugin.json); x=$(jq -r .version .codex-plugin/plugin.json); [ \"$c\" = \"$x\" ] || { echo \"version drift: .claude-plugin/plugin.json=$c .codex-plugin/plugin.json=$x\" >&2; exit 1; }"
     },
     {
       "label": "hook tests",