diff --git a/src/ctapipe/core/tests/test_traits.py b/src/ctapipe/core/tests/test_traits.py
index 06a7e4500e8..c84b0da185f 100644
--- a/src/ctapipe/core/tests/test_traits.py
+++ b/src/ctapipe/core/tests/test_traits.py
@@ -351,11 +351,11 @@ class MyTool(Tool):
         run_tool(tool, ["--MyTool.energy=5 m"], raises=True)
 
     captured = capsys.readouterr()
-    assert (
-        captured.err.split(":")[-1]
-        == f" Given quantity is of physical type {u.get_physical_type(5 * u.m)}."
-        + f" Expected {u.physical.energy}.\n"
+    expected = (
+        f" Given quantity is of physical type {u.get_physical_type(5 * u.m)}."
+        f" Expected {u.physical.energy}.\n"
     )
+    assert expected in captured.err
 
 
 def test_quantity_none():
diff --git a/src/ctapipe/core/tool.py b/src/ctapipe/core/tool.py
index 6325c909b53..40b055e70f6 100644
--- a/src/ctapipe/core/tool.py
+++ b/src/ctapipe/core/tool.py
@@ -403,6 +403,7 @@ def run(self, argv=None, raises=False):
         #  https://tldp.org/LDP/abs/html/exitcodes.html
 
         exit_status = 0
+        current_exception = None
 
         with self._exit_stack:
             try:
@@ -429,14 +430,13 @@ def run(self, argv=None, raises=False):
                 self.log.info("Finished: %s", self.name)
                 Provenance().finish_activity(activity_name=self.name)
             except (ToolConfigurationError, TraitError) as err:
+                current_exception = err
                 self.log.error("%s", err)
                 self.log.error("Use --help for more info")
                 exit_status = 2  # wrong cmd line parameter
                 Provenance().finish_activity(
                     activity_name=self.name, status="error", exit_code=exit_status
                 )
-                if raises:
-                    raise
             except KeyboardInterrupt:
                 self.log.warning("WAS INTERRUPTED BY CTRL-C")
                 exit_status = 130  # Script terminated by Control-C
@@ -444,6 +444,7 @@ def run(self, argv=None, raises=False):
                     activity_name=self.name, status="interrupted", exit_code=exit_status
                 )
             except Exception as err:
+                current_exception = err
                 exit_status = getattr(err, "exit_code", 1)
                 if exit_status == 1:
                     self.log.exception("Caught unexpected exception: %s", err)
@@ -452,17 +453,14 @@ def run(self, argv=None, raises=False):
                 Provenance().finish_activity(
                     activity_name=self.name, status="error", exit_code=exit_status
                 )
-                if raises:
-                    raise
             except SystemExit as err:
                 exit_status = err.code
                 if exit_status == 0:
                     # Finish normally
                     Provenance().finish_activity(activity_name=self.name)
                 else:
-                    if raises:
-                        raise
                     # Finish with error
+                    current_exception = err
                     self.log.critical(
                         "Caught SystemExit with exit code %s", exit_status
                     )
@@ -474,6 +472,8 @@ def run(self, argv=None, raises=False):
             finally:
                 if not {"-h", "--help", "--help-all"}.intersection(self.argv):
                     self.write_provenance()
+                if raises and current_exception:
+                    raise current_exception
 
         self.exit(exit_status)