diff --git a/src/index.js b/src/index.js
index 448d29c..5eecbac 100644
--- a/src/index.js
+++ b/src/index.js
@@ -18,6 +18,7 @@ async function main() {
       setPagesPath({ staticSiteGenerator, generatorConfigFile, path: siteUrl.pathname })
     }
     outputPagesBaseUrl(siteUrl)
+    core.exportVariable('GITHUB_PAGES', true)
   } catch (error) {
     core.setFailed(error)
     process.exit(1)