diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7f81f5a..b6ddd56 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,5 +12,24 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: '22'
+      - name: JSONs válidos + versões plugin.json ↔ marketplace.json
+        run: |
+          node -e '
+            const fs = require("fs");
+            const mp = JSON.parse(fs.readFileSync(".claude-plugin/marketplace.json", "utf8"));
+            let fail = 0;
+            for (const p of mp.plugins) {
+              // source em objeto = plugin externo (github/url), versionado upstream:
+              // não existe plugin.json local para comparar.
+              if (typeof p.source !== "string") continue;
+              const pj = JSON.parse(fs.readFileSync(`${p.source.replace(/^\.\//,"")}/.claude-plugin/plugin.json`, "utf8"));
+              if (pj.version !== p.version) {
+                console.error(`DRIFT: ${p.name} plugin.json=${pj.version} marketplace=${p.version}`);
+                fail = 1;
+              }
+            }
+            process.exit(fail);
+          '
+
       - name: Suíte de testes
         run: tests/run-all.sh