fix(cli): handle startup interrupts gracefully

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Bug Fixes
+
+- **cli:** handle interrupts during CLI startup without a traceback
+
 ## [0.2.49](https://github.com/promptfoo/modelaudit/compare/v0.2.48...v0.2.49) (2026-06-25)
 
 ### Bug Fixes

modelaudit/__init__.py

@@ -8,13 +8,14 @@
 import sys
 from typing import TYPE_CHECKING
 
-from .scanner_results import Issue, IssueSeverity, ScanResult
-from .version import __version__
-
 if TYPE_CHECKING:
     from modelaudit.core import scan_file as scan_file
     from modelaudit.core import scan_model_directory_or_file as scan_model_directory_or_file
+    from modelaudit.scanner_results import Issue as Issue
+    from modelaudit.scanner_results import IssueSeverity as IssueSeverity
+    from modelaudit.scanner_results import ScanResult as ScanResult
     from modelaudit.scanners.base import BaseScanner as BaseScanner
+    from modelaudit.version import __version__ as __version__
 
 if sys.version_info < (3, 10):  # noqa: UP036 — intentional safety net for bypassed requires-python
     import warnings
@@ -28,6 +29,10 @@
 
 # Public API — lazy-loaded to avoid circular imports at package init time.
 _LAZY_IMPORTS: dict[str, tuple[str, str]] = {
+    "Issue": ("modelaudit.scanner_results", "Issue"),
+    "IssueSeverity": ("modelaudit.scanner_results", "IssueSeverity"),
+    "ScanResult": ("modelaudit.scanner_results", "ScanResult"),
+    "__version__": ("modelaudit.version", "__version__"),
     "scan_file": ("modelaudit.core", "scan_file"),
     "scan_model_directory_or_file": ("modelaudit.core", "scan_model_directory_or_file"),
     "BaseScanner": ("modelaudit.scanners.base", "BaseScanner"),

modelaudit/__main__.py

@@ -1,6 +1,34 @@
 """Entry point for running modelaudit as a module with python -m modelaudit."""
 
-from .cli import main
+import signal
+import sys
+from types import FrameType
+
+
+class _StartupInterrupted(BaseException):
+    """Keep Click from converting a startup SIGINT into a generic abort."""
+
+
+def _raise_startup_interrupt(signum: int, frame: FrameType | None) -> None:
+    del signum, frame
+    raise _StartupInterrupted
+
+
+def _run() -> None:
+    """Run the CLI while keeping startup interrupts user-friendly."""
+    original_sigint_handler = signal.signal(signal.SIGINT, _raise_startup_interrupt)
+    try:
+        # Keep this import inside the guard: CLI imports can take long enough for
+        # a user to interrupt before the scan-specific handler is installed.
+        from .cli import main
+
+        main()
+    except (_StartupInterrupted, KeyboardInterrupt):
+        print("Scan interrupted by user", file=sys.stderr)
+        raise SystemExit(2) from None
+    finally:
+        signal.signal(signal.SIGINT, original_sigint_handler)
+
 
 if __name__ == "__main__":
-    main()
+    _run()

pyproject.toml

@@ -148,7 +148,7 @@ all = [
 ]
 
 [project.scripts]
-modelaudit = "modelaudit.cli:main"
+modelaudit = "modelaudit.__main__:_run"
 
 [project.urls]
 Repository = "https://github.com/promptfoo/modelaudit"

tests/conftest.py

@@ -151,6 +151,7 @@ def pytest_runtest_setup(item):
             "test_base_scanner.py",
             "test_core.py",
             "test_cli.py",
+            "test_interrupt_handling.py",  # CLI startup and scan interruption regressions
             "test_sarif_formatter.py",  # SARIF output and credential-redaction regressions
             "test_sarif_redaction.py",  # SARIF exported source credential-redaction regressions
             "test_directory_file_filtering.py",  # Directory prefilter regression tests

tests/utils/helpers/test_interrupt_handling.py

@@ -1,5 +1,7 @@
 """Test interrupt handling functionality."""
 
+import builtins
+import runpy
 import signal
 import subprocess
 import sys
@@ -10,6 +12,47 @@
 import pytest
 
 
+def test_module_entrypoint_handles_interrupt_during_cli_import(
+    monkeypatch: pytest.MonkeyPatch, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """Startup Ctrl+C should not leak a raw import traceback."""
+    original_import = builtins.__import__
+
+    def interrupt_cli_import(
+        name: str,
+        globals: dict[str, object] | None = None,
+        locals: dict[str, object] | None = None,
+        fromlist: tuple[str, ...] = (),
+        level: int = 0,
+    ) -> object:
+        if name == "cli" and level == 1:
+            raise KeyboardInterrupt
+        return original_import(name, globals, locals, fromlist, level)
+
+    monkeypatch.setattr(builtins, "__import__", interrupt_cli_import)
+
+    with pytest.raises(SystemExit, match="2"):
+        runpy.run_module("modelaudit", run_name="__main__")
+
+    assert capsys.readouterr().err == "Scan interrupted by user\n"
+
+
+def test_package_init_defers_scanner_result_imports() -> None:
+    """Package discovery must stay lightweight until the startup guard runs."""
+    result = subprocess.run(
+        [
+            sys.executable,
+            "-c",
+            "import modelaudit, sys; assert 'modelaudit.scanner_results' not in sys.modules",
+        ],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+
+    assert result.returncode == 0, result.stderr
+
+
 def test_interrupt_handler_basic():
     """Test basic interrupt handler functionality."""
     from modelaudit.utils.helpers.interrupt_handler import (