diff --git a/docs/introduction/configuration.md b/docs/introduction/configuration.md
index 8e9dc59..579740c 100644
--- a/docs/introduction/configuration.md
+++ b/docs/introduction/configuration.md
@@ -1,5 +1,13 @@
 # Configuration
 
+## Debug mode
+
+`service_debug` defaults to `False`. Debug mode puts tracebacks in error responses, so keep it off in production.
+
+- FastAPI: when lite-bootstrap builds the app because no `application` was passed, it sets the app's `debug` to `service_debug`. An app you pass in keeps its own `debug`.
+- Litestar: the app runs in debug mode when `service_debug=True` or `AppConfig(debug=True)`. Either one turns it on, and neither turns the other off.
+- FastStream, FastMCP and the free bootstrapper don't use it.
+
 ## Sentry
 
 Sentry integration uses `sentry_sdk` package under the hood.
diff --git a/lite_bootstrap/bootstrappers/litestar_bootstrapper.py b/lite_bootstrap/bootstrappers/litestar_bootstrapper.py
index 4857abd..b819a54 100644
--- a/lite_bootstrap/bootstrappers/litestar_bootstrapper.py
+++ b/lite_bootstrap/bootstrappers/litestar_bootstrapper.py
@@ -501,7 +501,7 @@ def __init__(self, bootstrap_config: LitestarConfig) -> None:
         self._attach_teardown_once(application_config, lambda: self._apply_config(application_config))
 
     def _apply_config(self, application_config: "AppConfig") -> None:
-        application_config.debug = self.bootstrap_config.service_debug
+        application_config.debug = application_config.debug or self.bootstrap_config.service_debug
         # An Empty value reaches layer resolution and 500s every body-reading handler.
         if application_config.request_max_body_size is Empty:
             application_config.request_max_body_size = _LITESTAR_DEFAULT_REQUEST_MAX_BODY_SIZE
diff --git a/lite_bootstrap/instruments/base.py b/lite_bootstrap/instruments/base.py
index 3e619f3..a0991a1 100644
--- a/lite_bootstrap/instruments/base.py
+++ b/lite_bootstrap/instruments/base.py
@@ -13,7 +13,7 @@ class BaseConfig:
     service_description: str | None = None
     service_version: str = "1.0.0"
     service_environment: str | None = None
-    service_debug: bool = True
+    service_debug: bool = False
     # Deprecated field name -> the field that replaced it. The deprecated field defaults to UNSET.
     _renamed_fields: typing.ClassVar[Mapping[str, str]] = {}
 
diff --git a/tests/test_config.py b/tests/test_config.py
index f680f19..cb5bdf7 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -72,7 +72,7 @@ class Source:
     config = BaseConfig.from_object(Source())
     assert config.service_name == "micro-service"
     assert config.service_version == "1.0.0"
-    assert config.service_debug is True
+    assert config.service_debug is False
 
 
 def test_from_object_preserves_falsy_values() -> None:
diff --git a/tests/test_fastapi_bootstrap.py b/tests/test_fastapi_bootstrap.py
index 36f47ea..8efe798 100644
--- a/tests/test_fastapi_bootstrap.py
+++ b/tests/test_fastapi_bootstrap.py
@@ -206,6 +206,17 @@ def test_app_property_raises_when_application_unset() -> None:
         _ = config.app
 
 
+@pytest.mark.parametrize(
+    ("config_kwargs", "expected_debug"),
+    [
+        pytest.param({}, False, id="default"),
+        pytest.param({"service_debug": True}, True, id="service-debug-on"),
+    ],
+)
+def test_built_app_debug_follows_service_debug(config_kwargs: dict[str, typing.Any], expected_debug: bool) -> None:
+    assert FastAPIConfig(**config_kwargs).app.debug is expected_debug
+
+
 def test_user_supplied_app_keeps_title_version_debug() -> None:
     user_app = fastapi.FastAPI(title="user-title", version="9.9.9", debug=False)
     config = FastAPIConfig(
diff --git a/tests/test_litestar_bootstrap.py b/tests/test_litestar_bootstrap.py
index 9e3d7e8..74ba797 100644
--- a/tests/test_litestar_bootstrap.py
+++ b/tests/test_litestar_bootstrap.py
@@ -520,6 +520,24 @@ def test_litestar_bootstrap_keeps_explicit_unlimited_request_max_body_size(lites
         assert application.request_max_body_size is None
 
 
+@pytest.mark.parametrize(
+    ("application_config", "config_kwargs", "expected_debug"),
+    [
+        pytest.param(AppConfig(), {}, False, id="default"),
+        pytest.param(AppConfig(debug=False), {}, False, id="app-config-debug-off"),
+        pytest.param(AppConfig(debug=True), {}, True, id="app-config-debug-on"),
+        pytest.param(AppConfig(), {"service_debug": True}, True, id="service-debug-on"),
+    ],
+)
+def test_litestar_debug_follows_app_config_and_service_debug(
+    application_config: AppConfig, config_kwargs: dict[str, typing.Any], expected_debug: bool
+) -> None:
+    config = LitestarConfig(application_config=application_config, **config_kwargs)
+    application = LitestarBootstrapper(bootstrap_config=config).bootstrap()
+
+    assert application.debug is expected_debug
+
+
 def test_litestar_default_request_max_body_size_matches_litestar() -> None:
     """Guard: our constant must stay equal to the default Litestar's own __init__ applies."""
     litestar_default = inspect.signature(litestar.Litestar.__init__).parameters["request_max_body_size"].default