CoplayDev/unity-mcp · error · EditorNotFound

No Unity editor binary found. Searched:\n

Error message

No Unity editor binary found. Searched:\n  

What it means

Raised by LocalLauncher.resolve_editor when resolve_version(project_path) returned an empty value, so the harness cannot even begin searching for an editor binary. Because no version was resolved, the searched list is empty and __str__ prints 'No Unity editor binary found. Searched:\n ' with no paths.

Source

Thrown at tools/local_harness.py:752

class Handle:
    """A live editor handle. Exactly one of (proc, container) is meaningful."""

    proc: Any = None  # subprocess.Popen for LocalLauncher
    container: str | None = None  # container name for DockerLauncher
    log_path: str | None = None
    pid: int | None = None


class LocalLauncher:
    """Boots a native Hub editor via detached Popen; PID-based liveness."""

    def __init__(self, args: argparse.Namespace):
        self.args = args

    def resolve_editor(self, project_path: Path) -> EditorSpec:
        version = self.args.unity_version or resolve_version(project_path)
        if not version:
            raise EditorNotFound(searched=[])
        return discover_editor(version, explicit_editor=self.args.editor)

    @staticmethod
    def warmup_argv(editor: str, project_path: Path, log_path: Path) -> list[str]:
        return [
            editor, "-batchmode", "-nographics", "-quit",
            "-projectPath", str(project_path),
            "-logFile", str(log_path),
        ]

    @staticmethod
    def resident_argv(editor: str, project_path: Path, log_path: Path,
                      extra_editor_args: list[str]) -> list[str]:
        return [
            editor, "-batchmode", "-nographics",
            "-projectPath", str(project_path),
            "-logFile", str(log_path),
            *list(extra_editor_args or []),

View on GitHub (pinned to c21bf496bc)

Solutions

1. Point --project-path at a real Unity project that contains ProjectSettings/ProjectVersion.txt.
2. Pass --unity-version 2022.3.0f1 explicitly to bypass ProjectVersion.txt parsing.
3. If the project is new, open it once in Unity Hub so ProjectVersion.txt is written.

Example fix

# before
python tools/local_harness.py --project-path /tmp/empty-folder  # no ProjectVersion.txt
# after
python tools/local_harness.py --project-path TestProjects/UnityMCPTests --unity-version 2022.3.0f1

version = args.unity_version or resolve_version(project_path)
if not version:
    raise SystemExit(f'{project_path} has no ProjectVersion.txt; pass --unity-version')

def has_project_version(p: pathlib.Path) -> bool:
    return (p / 'ProjectSettings' / 'ProjectVersion.txt').exists()

from tools.local_harness import EditorNotFound
try:
    spec = launcher.resolve_editor(project_path)
except EditorNotFound as e:
    if not e.searched:
        print('No version resolved; pass --unity-version'); sys.exit(5)
    raise

When it happens

Trigger: resolve_version reads ProjectSettings/ProjectVersion.txt and finds no m_EditorVersion: line (or the file is missing/empty), so version is falsy and resolve_editor raises EditorNotFound(searched=[]) at local_harness.py:749-750.

Common situations: The --project-path points at a folder that is not a Unity project (no ProjectSettings/ProjectVersion.txt); the file is corrupted/empty; a fresh project template was not initialized by Unity yet.

Related errors

• No Unity editor binary found. Searched:\n {searched}
• {path}: expected 1 replacement for pattern, got {n}
• Could not generate a unique screenshot filename for '{fullPa
• Color array must have 3 or 4 elements.
• Port must be positive.

AI-assisted analysis of CoplayDev/unity-mcp@c21bf496bc (2026-08-13). Data as JSON: /api/errors/5728f073422a53f5. Report an issue: GitHub.