From abe33caddc381cbae03a9ad41fa36ed4c9b562e0 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 9 Apr 2026 14:40:00 +0000
Subject: [PATCH 1/3] Initial plan


From 8b1291f18477ef42e5d5c9b05218a2d9798ba837 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 9 Apr 2026 15:11:56 +0000
Subject: [PATCH 2/3] Suppress verbose tracebacks by default, show only with
 -vv

Install a custom sys.excepthook in the fre() entry point that suppresses
Python tracebacks at default and -v verbosity levels. At -vv (DEBUG), the
full traceback is shown. At lower levels, only the exception type and
message are printed, along with a hint to use 'fre -vv ...' for more
detail.

Closes #793

Agent-Logs-Url: https://github.com/NOAA-GFDL/fre-cli/sessions/d594a572-8566-467b-9a96-4b233d712582

Co-authored-by: ilaflott <6273252+ilaflott@users.noreply.github.com>
---
 docs/tools.rst            |  1 +
 fre/fre.py                | 11 +++++++++-
 fre/tests/test_fre_cli.py | 43 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/docs/tools.rst b/docs/tools.rst
index 8388ad560..afa5ae730 100644
--- a/docs/tools.rst
+++ b/docs/tools.rst
@@ -20,6 +20,7 @@ arguments
 * (optional) ``-v[v]``, verbosity flag, up to two
   
   - increments ``fre``'s verbosity from the default ``logging.WARNING`` to ``logging.INFO`` with one ``-v``, and again to ``logging.DEBUG`` with ``-vv``
+  - at default verbosity or ``-v``, unhandled exceptions print only the error message; use ``-vv`` to show the full traceback
 	
 * (optional) ``-q``, quiet flag, up to one
   
diff --git a/fre/fre.py b/fre/fre.py
index 25b717504..334258b85 100644
--- a/fre/fre.py
+++ b/fre/fre.py
@@ -5,6 +5,7 @@
 """
 
 import logging
+import sys
 
 import click
 
@@ -38,7 +39,8 @@
 )
 @click.option( '-v', '--verbose', default = 0, required = False, count = True, type = int,
                help = "Increment logging verbosity from default (logging.WARNING) to logging.INFO. " + \
-                      "use -vv for logging.DEBUG. will be overridden by -q/--quiet" )
+                      "use -vv for logging.DEBUG and to show full tracebacks on errors. " + \
+                      "will be overridden by -q/--quiet" )
 @click.option( '-q', '--quiet', default = False, required = False, is_flag = True, type = bool,
                help = "Set logging verbosity from default (logging.WARNING) to logging.ERROR, printing " + \
                       "less output to screen. overrides -v[v]/--verbose" )
@@ -79,3 +81,10 @@ def fre(verbose = 0, quiet = False, log_file = None):
         fre_logger.info('fre_file_handler added to base_fre_logger')
 
     fre_logger.debug('click entry-point function call done.')
+
+    # install custom exception hook to suppress tracebacks unless -vv is used
+    if log_level > logging.DEBUG:
+        def _brief_excepthook(exc_type, exc_value, exc_tb):
+            click.echo(f"{exc_type.__name__}: {exc_value}", err=True)
+            click.echo("(use 'fre -vv ...' for the full traceback)", err=True)
+        sys.excepthook = _brief_excepthook
diff --git a/fre/tests/test_fre_cli.py b/fre/tests/test_fre_cli.py
index f7fa283e8..56ad10fc0 100644
--- a/fre/tests/test_fre_cli.py
+++ b/fre/tests/test_fre_cli.py
@@ -10,6 +10,7 @@
   right and thinks the tool has a --optionDNE option)
 - fre --version, checking for version GTE current version (fails if version isn't defined)
 """
+import sys
 import subprocess
 from click.testing import CliRunner
 
@@ -50,3 +51,45 @@ def test_cli_fre_version():
 #    latest_testing_tag = result.stdout.split('\n')[0]
 #
 #    assert '2026.01.alpha2' == latest_testing_tag
+
+# ---- traceback suppression tests ----
+# These tests verify that unhandled exceptions print a clean error message
+# at default verbosity, and the full traceback only at -vv.
+
+_CLI_SCRIPT = """\
+import sys
+sys.argv = {argv!r}
+from fre.fre import fre
+fre(standalone_mode=True)
+"""
+
+def _run_fre_subprocess(argv):
+    """Helper: run fre via subprocess so sys.excepthook is exercised."""
+    return subprocess.run(
+        [sys.executable, "-c", _CLI_SCRIPT.format(argv=argv)],
+        capture_output=True, text=True
+    )
+
+def test_traceback_suppressed_by_default():
+    '''fre run function — default verbosity should suppress traceback'''
+    result = _run_fre_subprocess(["fre", "run", "function"])
+    assert result.returncode != 0
+    assert "NotImplementedError" in result.stderr
+    assert "Traceback" not in result.stderr
+    assert "fre -vv" in result.stderr
+
+def test_traceback_suppressed_with_single_v():
+    '''fre -v run function — single -v should still suppress traceback'''
+    result = _run_fre_subprocess(["fre", "-v", "run", "function"])
+    assert result.returncode != 0
+    assert "NotImplementedError" in result.stderr
+    assert "Traceback" not in result.stderr
+    assert "fre -vv" in result.stderr
+
+def test_traceback_shown_with_vv():
+    '''fre -vv run function — double -v should show full traceback'''
+    result = _run_fre_subprocess(["fre", "-vv", "run", "function"])
+    assert result.returncode != 0
+    assert "NotImplementedError" in result.stderr
+    assert "Traceback" in result.stderr
+    assert "fre -vv" not in result.stderr

From cf83c57424baf4e9d7b1f009c9fc1c8198a22546 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 9 Apr 2026 15:13:17 +0000
Subject: [PATCH 3/3] Fix em dashes in test docstrings per code review

Agent-Logs-Url: https://github.com/NOAA-GFDL/fre-cli/sessions/d594a572-8566-467b-9a96-4b233d712582

Co-authored-by: ilaflott <6273252+ilaflott@users.noreply.github.com>
---
 fre/tests/test_fre_cli.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fre/tests/test_fre_cli.py b/fre/tests/test_fre_cli.py
index 56ad10fc0..1d4131e6a 100644
--- a/fre/tests/test_fre_cli.py
+++ b/fre/tests/test_fre_cli.py
@@ -71,7 +71,7 @@ def _run_fre_subprocess(argv):
     )
 
 def test_traceback_suppressed_by_default():
-    '''fre run function — default verbosity should suppress traceback'''
+    '''fre run function - default verbosity should suppress traceback'''
     result = _run_fre_subprocess(["fre", "run", "function"])
     assert result.returncode != 0
     assert "NotImplementedError" in result.stderr
@@ -79,7 +79,7 @@ def test_traceback_suppressed_by_default():
     assert "fre -vv" in result.stderr
 
 def test_traceback_suppressed_with_single_v():
-    '''fre -v run function — single -v should still suppress traceback'''
+    '''fre -v run function - single -v should still suppress traceback'''
     result = _run_fre_subprocess(["fre", "-v", "run", "function"])
     assert result.returncode != 0
     assert "NotImplementedError" in result.stderr
@@ -87,7 +87,7 @@ def test_traceback_suppressed_with_single_v():
     assert "fre -vv" in result.stderr
 
 def test_traceback_shown_with_vv():
-    '''fre -vv run function — double -v should show full traceback'''
+    '''fre -vv run function - double -v should show full traceback'''
     result = _run_fre_subprocess(["fre", "-vv", "run", "function"])
     assert result.returncode != 0
     assert "NotImplementedError" in result.stderr