diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fd752f9..23d482f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -54,6 +54,7 @@ jobs:
             tests/test_agent_routing.py \
             tests/test_decision_engine_replay.py \
             tests/test_evaluate_agent_routing.py \
+            tests/test_gcp_artifact_workflow.py \
             tests/test_gcp_cloudsql_restore_drill.py \
             tests/test_gcp_cloudsql_restore_readback.py \
             tests/test_gcp_iam_split_apply.py \
diff --git a/.github/workflows/gcp-artifact.yml b/.github/workflows/gcp-artifact.yml
index 04dff76..a512de5 100644
--- a/.github/workflows/gcp-artifact.yml
+++ b/.github/workflows/gcp-artifact.yml
@@ -60,10 +60,14 @@ jobs:
             .
 
           docker run --rm "${image_uri}"
-          docker push "${image_uri}"
+          docker push "${image_uri}" | tee docker-push.log
+          image_digest="$(awk '/digest: sha256:/ {print $3}' docker-push.log | tail -1)"
+          test -n "${image_digest}"
 
           {
             echo "image_uri=${image_uri}"
+            echo "image_digest=${image_digest}"
+            echo "image_ref=${image_uri}@${image_digest}"
             echo "revision=${GITHUB_SHA}"
           } > gcp-artifact-image.txt
 
diff --git a/.github/workflows/gcp-readiness.yml b/.github/workflows/gcp-readiness.yml
index ac71aff..a299983 100644
--- a/.github/workflows/gcp-readiness.yml
+++ b/.github/workflows/gcp-readiness.yml
@@ -104,3 +104,13 @@ jobs:
           name: gcp-readiness
           path: ${{ env.READINESS_ARTIFACT_DIR }}/
           if-no-files-found: error
+
+      - name: Enforce readiness result
+        if: always()
+        shell: bash
+        run: |
+          code="$(cat "${READINESS_ARTIFACT_DIR}/gcp-infra-readiness.exitcode" 2>/dev/null || echo 1)"
+          if [ "${code}" != "0" ]; then
+            echo "GCP readiness checker failed with exit code ${code}. See the uploaded gcp-readiness artifact for exact failed checks."
+            exit "${code}"
+          fi
diff --git a/ops/check_gcp_infra_readiness.py b/ops/check_gcp_infra_readiness.py
index 49b30ee..68fdac9 100755
--- a/ops/check_gcp_infra_readiness.py
+++ b/ops/check_gcp_infra_readiness.py
@@ -185,6 +185,8 @@ def check_github_actions_artifact_ci() -> Check:
         GITHUB_ARTIFACT_SERVICE_ACCOUNT,
         "docker run --rm",
         "docker push",
+        "image_digest=",
+        "image_ref=",
     ]
     absent = [item for item in required_text if item not in text]
     if absent:
diff --git a/tests/test_gcp_artifact_workflow.py b/tests/test_gcp_artifact_workflow.py
new file mode 100644
index 0000000..56b33b5
--- /dev/null
+++ b/tests/test_gcp_artifact_workflow.py
@@ -0,0 +1,11 @@
+from pathlib import Path
+
+
+def test_gcp_artifact_workflow_retains_immutable_image_digest() -> None:
+    workflow = Path(".github/workflows/gcp-artifact.yml").read_text()
+
+    assert "docker push" in workflow
+    assert "tee docker-push.log" in workflow
+    assert "image_digest=" in workflow
+    assert "image_ref=" in workflow
+    assert "test -n \"${image_digest}\"" in workflow
diff --git a/tests/test_gcp_readiness_workflow.py b/tests/test_gcp_readiness_workflow.py
index 0454440..57772f4 100644
--- a/tests/test_gcp_readiness_workflow.py
+++ b/tests/test_gcp_readiness_workflow.py
@@ -9,4 +9,6 @@ def test_gcp_readiness_workflow_uses_uploadable_artifact_dir() -> None:
     assert "READINESS_ARTIFACT_DIR: gcp-readiness-artifacts" in workflow
     assert 'mkdir -p "${READINESS_ARTIFACT_DIR}"' in workflow
     assert "path: ${{ env.READINESS_ARTIFACT_DIR }}/" in workflow
+    assert "Enforce readiness result" in workflow
+    assert "GCP readiness checker failed" in workflow
     assert "path: .gcp-readiness/" not in workflow