diff --git a/.github/workflows/__start-proxy.yml b/.github/workflows/__start-proxy.yml
index 789a9f5b27..2a361ed31e 100644
--- a/.github/workflows/__start-proxy.yml
+++ b/.github/workflows/__start-proxy.yml
@@ -71,5 +71,10 @@ jobs:
           echo "${{ steps.proxy.outputs.proxy_host }}"
           echo "${{ steps.proxy.outputs.proxy_port }}"
           echo "${{ steps.proxy.outputs.proxy_urls }}"
+
+      - name: Fail if proxy outputs are not set
+        if: (!steps.proxy.outputs.proxy_host) || (!steps.proxy.outputs.proxy_port)
+          || (!steps.proxy.outputs.proxy_ca_certificate) || (!steps.proxy.outputs.proxy_urls)
+        run: exit 1
     env:
       CODEQL_ACTION_TEST_MODE: true
diff --git a/pr-checks/checks/start-proxy.yml b/pr-checks/checks/start-proxy.yml
index c53aef575a..b918b7a63f 100644
--- a/pr-checks/checks/start-proxy.yml
+++ b/pr-checks/checks/start-proxy.yml
@@ -19,3 +19,7 @@ steps:
       echo "${{ steps.proxy.outputs.proxy_host }}"
       echo "${{ steps.proxy.outputs.proxy_port }}"
       echo "${{ steps.proxy.outputs.proxy_urls }}"
+
+  - name: Fail if proxy outputs are not set
+    if: (!steps.proxy.outputs.proxy_host) || (!steps.proxy.outputs.proxy_port) || (!steps.proxy.outputs.proxy_ca_certificate) || (!steps.proxy.outputs.proxy_urls)
+    run: exit 1