diff --git a/dsd_pythonanywhere/platform_deployer.py b/dsd_pythonanywhere/platform_deployer.py
index 8747d52..4aa8b5d 100644
--- a/dsd_pythonanywhere/platform_deployer.py
+++ b/dsd_pythonanywhere/platform_deployer.py
@@ -210,7 +210,7 @@ def _modify_wsgi(self):
         }
         contents = plugin_utils.get_template_string(template_path, context)
         path = dsd_config.project_root / dsd_config.local_project_name / "wsgi.py"
-        plugin_utils.add_file(path, contents)
+        plugin_utils.modify_file(path, contents)
 
     def _modify_gitignore(self) -> None:
         """Ensure .gitignore ignores deployment files."""
diff --git a/tests/unit_tests/test_platform_deployer.py b/tests/unit_tests/test_platform_deployer.py
index e929a69..a5a36b2 100644
--- a/tests/unit_tests/test_platform_deployer.py
+++ b/tests/unit_tests/test_platform_deployer.py
@@ -57,6 +57,31 @@ def test_modify_settings(tmp_path: Path, monkeypatch):
     assert 'ALLOWED_HOSTS = ["testuser.pythonanywhere.com"]' in modified_content
 
 
+def test_modify_wsgi_redeploy_does_not_prompt(tmp_path: Path, monkeypatch, mocker):
+    """_modify_wsgi overwrites an existing wsgi.py without a confirmation prompt."""
+    project_name = "mysite"
+    project_dir = tmp_path / project_name
+    project_dir.mkdir()
+    wsgi_path = project_dir / "wsgi.py"
+    wsgi_path.write_text("# original wsgi.py")
+
+    deployer = PlatformDeployer()
+    monkeypatch.setattr(dsd_config, "project_root", tmp_path)
+    monkeypatch.setattr(dsd_config, "local_project_name", project_name)
+    monkeypatch.setattr(dsd_config, "stdout", sys.stdout)
+    mocker.patch.object(deployer, "_get_repo_name", return_value="myrepo")
+
+    # wsgi.py already exists here, as it would on a redeploy. If this used
+    # add_file(), it would block on an interactive confirmation prompt.
+    deployer._modify_wsgi()
+    modified_content = wsgi_path.read_text()
+    assert "myrepo" in modified_content
+    assert project_name in modified_content
+
+    deployer._modify_wsgi()
+    assert wsgi_path.read_text() == modified_content
+
+
 def test_add_requirements(tmp_path: Path, monkeypatch):
     """_add_requirements adds required packages."""
     requirements_path = tmp_path / "requirements.txt"