nexu-io/open-design · error · SystemExit

Refusing to overwrite unmanaged output directory: {output_di

Error message

Refusing to overwrite unmanaged output directory: {output_dir}. Only directories containing {BUNDLE_MARKER} can be replaced with --force.

What it means

Thrown by validate_output_dir() when --force is passed and the output dir already exists, but it does not contain the BUNDLE_MARKER file (.chat-motion-overlay-bundle). The marker is the trust signal that the directory was created by this tool; without it --force refuses to delete the tree to avoid wiping unrelated content.

Source

Thrown at skills/chat-motion-overlay/scripts/prepare_chat_overlay_bundle.py:62

def bundle_marker_path(output_dir: Path) -> Path:
    return output_dir / BUNDLE_MARKER


def validate_output_dir(output_dir: Path, force: bool) -> None:
    dangerous_targets = {
        Path.cwd().resolve(),
        Path.home().resolve(),
        repo_root(),
        skill_root(),
        template_dir(),
    }
    if output_dir in dangerous_targets:
        raise SystemExit(
            f"Refusing to use dangerous output directory: {output_dir}. "
            "Choose a dedicated generated-bundle directory instead."
        )
    if output_dir.exists() and force and not bundle_marker_path(output_dir).exists():
        raise SystemExit(
            f"Refusing to overwrite unmanaged output directory: {output_dir}. "
            f"Only directories containing {BUNDLE_MARKER} can be replaced with --force."
        )


def copy_template(output_dir: Path, force: bool) -> None:
    validate_output_dir(output_dir, force)
    if output_dir.exists():
        if not force:
            raise SystemExit(f"Output directory already exists: {output_dir}. Use --force to overwrite.")
        shutil.rmtree(output_dir)
    shutil.copytree(template_dir(), output_dir)
    bundle_marker_path(output_dir).write_text("generated by chat-motion-overlay\n", encoding="utf-8")


def write_chat_spec_ts(spec: dict, output_dir: Path) -> None:
    target = output_dir / "src" / "chatSpec.ts"
    content = "export const chatSpec = " + json.dumps(spec, ensure_ascii=False, indent=2) + " as const;\n"

View on GitHub (pinned to 5be4028344)

Solutions

Point --output-dir at a fresh dedicated directory this tool can own end-to-end.
If the existing directory is safe to delete, remove it manually first (rm -rf) then run without --force, so the tool creates and marks it.
If you are sure the directory is tool-managed but lost its marker, create an empty .chat-motion-overlay-bundle file inside it before re-running with --force.

Example fix

# before
python prepare_chat_overlay_bundle.py --output-dir ./existing-build --force  # no marker inside
# after
rm -rf ./existing-build && python prepare_chat_overlay_bundle.py --output-dir ./existing-build

Defensive patterns

Strategy: validation

Validate before calling

from pathlib import Path
MARKER = ".chat-motion-overlay-bundle"
def assert_managed_or_empty(output_dir: Path, force: bool) -> None:
    if output_dir.exists() and force and not (output_dir / MARKER).exists():
        raise SystemExit(f"{output_dir} is not tool-managed (no {MARKER}); remove it manually first")

Prevention

Let the tool create its own output directories so the marker is always present.
Never reuse foreign build folders for bundle output.

When it happens

Trigger: Run prepare_chat_overlay_bundle.py --output-dir <existing dir> --force where <existing dir> was created by something else (or by this tool before markers existed) and lacks the .chat-motion-overlay-bundle file.

Common situations: Reusing a generic build/dist folder that predates the marker; manually creating the output directory; pointing at a directory another generator owns.

Related errors

AI-assisted analysis of nexu-io/open-design@5be4028344 (2026-08-12). Data as JSON: /api/errors/e727eb319222b27e. Report an issue: GitHub.