diff --git a/python/remage/logging.py b/python/remage/logging.py
index 99826785..f7d8f594 100644
--- a/python/remage/logging.py
+++ b/python/remage/logging.py
@@ -65,12 +65,23 @@ def setup_log() -> logging.Logger:
     logger.setLevel(logging.DEBUG)
     logger.propagate = False
 
-    if supports_color():
-        fmt = "%(log_color)s[%(levelname)-7s ->%(reset)s %(message)s"
+    # Avoid adding duplicate handlers if setup_log() is called multiple times.
+    if not any(getattr(h, "_remage_default_handler", False) for h in logger.handlers):
+        # Keep the visible formatting identical between colored and non-colored output.
+        plain_fmt = "[%(levelname)-7s -> %(message)s"
+        colored_fmt = "%(log_color)s[%(levelname)-7s ->%(reset)s %(message)s"
+
+        if supports_color():
+            handler = colorlog.StreamHandler()
+            handler.setFormatter(
+                colorlog.ColoredFormatter(colored_fmt, log_colors=LEVEL_COLORS)
+            )
+        else:
+            handler = logging.StreamHandler()
+            handler.setFormatter(logging.Formatter(plain_fmt))
 
-        handler = colorlog.StreamHandler()
-        handler.setFormatter(colorlog.ColoredFormatter(fmt, log_colors=LEVEL_COLORS))
         handler.setLevel(logging.DEBUG)
+        handler._remage_default_handler = True  # type: ignore[attr-defined]
         logger.addHandler(handler)
 
     set_logging_level(logger, "Summary")
@@ -96,7 +107,7 @@ def supports_color() -> bool:
         "vt100",
         "xterm",
     ]
-    return sys.stderr.isatty() and any(term in t for t in terms)
+    return sys.stderr.isatty() and term is not None and any(t in term for t in terms)
 
 
 def set_logging_level(logger, rmg_log_level):
diff --git a/src/RMGManager.cc b/src/RMGManager.cc
index 87ff5bfd..9b47c743 100644
--- a/src/RMGManager.cc
+++ b/src/RMGManager.cc
@@ -328,7 +328,7 @@ void RMGManager::SetRandEngineSeed(int seed) {
     );
     CLHEP::HepRandom::setTheSeed(0);
   } else CLHEP::HepRandom::setTheSeed(seed);
-  RMGLog::Out(RMGLog::summary, "CLHEP::HepRandom seed set to: ", seed);
+  RMGLog::Out(RMGLog::summary, "CLHEP::HepRandom seed changed to: ", seed, " (user value)");
 
   fIsRandControlled = true;
 }
@@ -341,7 +341,12 @@ void RMGManager::SetRandEngineInternalSeed(int index) {
 
   int array_index = index % 2;
   CLHEP::HepRandom::setTheSeed(seeds[array_index]);
-  RMGLog::Out(RMGLog::summary, "CLHEP::HepRandom seed set to: ", seeds[array_index]);
+  RMGLog::Out(
+      RMGLog::summary,
+      "CLHEP::HepRandom seed changed to: ",
+      seeds[array_index],
+      " (from the internal seed table)"
+  );
 
   fIsRandControlled = true;
 }
@@ -351,7 +356,7 @@ void RMGManager::SetRandSystemEntropySeed() {
   std::random_device rd; // uses RDRND or /dev/urandom
   auto rand_seed = dist(rd);
   CLHEP::HepRandom::setTheSeed(rand_seed);
-  RMGLog::Out(RMGLog::summary, "CLHEP::HepRandom seed set to: ", rand_seed);
+  RMGLog::Out(RMGLog::summary, "CLHEP::HepRandom seed changed to: ", rand_seed, " (from system entropy)");
 }
 
 void RMGManager::DefineCommands() {
diff --git a/src/RMGRunAction.cc b/src/RMGRunAction.cc
index 7ffed27e..62a17bb1 100644
--- a/src/RMGRunAction.cc
+++ b/src/RMGRunAction.cc
@@ -400,7 +400,7 @@ void RMGRunAction::PostprocessOutputFile() const {
 
   try {
     fs::rename(worker_tmp, worker_lh5);
-    RMGLog::Out(RMGLog::summary, "Moved output file ", worker_tmp.string(), " to ", worker_lh5.string());
+    RMGLog::Out(RMGLog::detail, "Moved output file ", worker_tmp.string(), " to ", worker_lh5.string());
   } catch (const fs::filesystem_error& e) {
     RMGLog::Out(
         RMGLog::error,
diff --git a/tests/basics/CMakeLists.txt b/tests/basics/CMakeLists.txt
index 05dc0602..8d123de8 100644
--- a/tests/basics/CMakeLists.txt
+++ b/tests/basics/CMakeLists.txt
@@ -29,4 +29,4 @@ add_test(NAME basics/rand-seed
          COMMAND ${REMAGE_PYEXE} -g gdml/geometry.gdml -o none --rand-seed 123
                  --macro-substitutions ENERGY=1000 GENERATOR=GPS -- macros/run.mac)
 set_tests_properties(basics/rand-seed PROPERTIES PASS_REGULAR_EXPRESSION
-                                                 "CLHEP::HepRandom seed set to: 123")
+                                                 "CLHEP::HepRandom seed changed to: 123")
diff --git a/tests/confinement/test_basic_surface.py b/tests/confinement/test_basic_surface.py
index 4b2114bc..01c96c4a 100644
--- a/tests/confinement/test_basic_surface.py
+++ b/tests/confinement/test_basic_surface.py
@@ -35,7 +35,7 @@ def add_local_pos(vertices, pos):
     return vertices
 
 
-tol = 1e-6
+tol = 1e-6  # mm
 select_sides = {
     "tubby": {
         "func": [
@@ -209,7 +209,10 @@ def add_local_pos(vertices, pos):
     indices[is_close] = idx
 
 if len(indices[indices == -1]) > 0:
-    msg = f"{dtype} has primaries not close to any side"
+    msg = (
+        f"{dtype} has {len(indices[indices == -1])} in {len(vertices)} "
+        f"primaries not close to any side with absolute tolerance {tol} mm"
+    )
     raise ValueError(msg)
 
 vertices["idx"] = indices