diff --git a/.github/scripts/smoke_test_large_models.py b/.github/scripts/smoke_test_large_models.py
index d9f0514c..e1d8a93b 100644
--- a/.github/scripts/smoke_test_large_models.py
+++ b/.github/scripts/smoke_test_large_models.py
@@ -48,15 +48,25 @@ def check_model(module_path, model):
     )
     match tlc_result:
         case TimeoutExpired():
-            logging.debug(tlc_result.stdout)
+            args, _ = tlc_result.args
+            logging.debug(' '.join(args))
+            logging.debug(
+                # Returns string on Windows, bytes everywhere else
+                tlc_result.stdout
+                if type(tlc_result.stdout) == str
+                else tlc_result.stdout.decode('utf-8')
+            )
             return True
         case CompletedProcess():
+            output = ' '.join(tlc_result.args) + '\n' + tlc_result.stdout
             logging.warning(f'Model {model_path} finished quickly, within {smoke_test_timeout_in_seconds} seconds; consider labeling it a small model')
             expected_result = model['result']
             actual_result = tla_utils.resolve_tlc_exit_code(tlc_result.returncode)
-            if expected_result != actual_result:
+            if expected_result == actual_result:
+                logging.debug(output)
+            else:
                 logging.error(f'Model {model_path} expected result {expected_result} but got {actual_result}')
-                logging.error(tlc_result.stdout)
+                logging.error(output)
                 return False
             return True
         case _:
diff --git a/.github/scripts/tla_utils.py b/.github/scripts/tla_utils.py
index 9d22bc95..6ee02a1b 100644
--- a/.github/scripts/tla_utils.py
+++ b/.github/scripts/tla_utils.py
@@ -52,8 +52,8 @@ def write_json(data, path):
 
 def parse_module(examples_root, parser, path):
     """
-    Parses a .tla file; returns the parse tree along with whether a parse
-    error was detected.
+    Parses a .tla file with tree-sitter; returns the parse tree along with
+    whether a parse error was detected.
     """
     module_text = None
     path = from_cwd(examples_root, path)
diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index dae34ad5..aa2c16e8 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -15,8 +15,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        # macOS not used; see https://github.com/tlaplus/Examples/issues/119
-        os: [windows-latest, ubuntu-latest]
+        os: [windows-latest, ubuntu-latest, macos-latest]
         unicode: [true, false]
       fail-fast: false
     env: