diff --git a/src/lib/ci-deploy.test.ts b/src/lib/ci-deploy.test.ts
index 303d9bfc..170fbc2b 100644
--- a/src/lib/ci-deploy.test.ts
+++ b/src/lib/ci-deploy.test.ts
@@ -169,6 +169,17 @@ describe("deployment transaction", () => {
 		expect(result.output).toContain("No previous container exists");
 		expect(result.app).toBeNull();
 	});
+	// The image is tagged with the commit SHA, so a dirty tree would ship
+	// uncommitted code under a label that claims otherwise. The guard has to
+	// stop the release before anything is built or migrated.
+	it("refuses to release from a dirty working tree", () => {
+		const result = simulate("dirty-tree");
+		expect(result.status, result.output).not.toBe(0);
+		expect(result.output).toContain("de werkboom is niet schoon");
+		expect(result.calls).not.toContain("docker build");
+		expect(result.calls).not.toContain("pnpm db:migrate");
+		expect(result.calls).not.toContain("docker run");
+	});
 });
 
 describe("legacy and CI container coexistence", () => {
diff --git a/src/test/ci-deploy-harness.sh b/src/test/ci-deploy-harness.sh
index 64dfdb01..7c50faf1 100644
--- a/src/test/ci-deploy-harness.sh
+++ b/src/test/ci-deploy-harness.sh
@@ -1,6 +1,14 @@
 # Sourced only by the deployment simulation tests; no external services are used.
 git() {
   if [ "$1" = rev-parse ]; then printf '%s\n' "$TEST_SHA"; return; fi
+  # `git status --porcelain` is the script's clean-tree guard: empty stdout
+  # means clean, any output aborts the release before it builds an image. It
+  # needs its own stub — falling through to the ls-remote-shaped printf below
+  # would always report a dirty tree and fail every scenario.
+  if [ "$1" = status ]; then
+    [ "$SCENARIO" = dirty-tree ] && printf ' M src/leaked-file.ts\n'
+    return 0
+  fi
   local n=0
   if [ -f "$TEST_DIR/remote-count" ]; then read -r n < "$TEST_DIR/remote-count"; fi
   n=$((n+1)); printf '%s\n' "$n" > "$TEST_DIR/remote-count"