langchain-ai/deepagents · error · ExtensionError

Could not import extension {source.path}

Error message

Could not import extension {source.path}

What it means

Raised by _import_factory in the extension loader when importlib cannot produce a module spec/loader for the extension file at source.path. The extension module could not even be loaded, so the extension fails to install.

Source

Thrown at libs/code/deepagents_code/extensions/loader.py:40

def _extension_module_name(path: Path) -> str:
    digest = hashlib.sha256(str(path.resolve()).encode()).hexdigest()[:16]
    return f"deepagents_code_extension_{digest}"


def _import_factory(
    source: SourceInfo,
) -> tuple[str, Callable[[ExtensionAPI], Awaitable[None]]]:
    name = _extension_module_name(source.path)
    spec = importlib.util.spec_from_file_location(
        name,
        source.path,
        submodule_search_locations=[str(source.path.parent)]
        if source.is_package
        else None,
    )
    if spec is None or spec.loader is None:
        msg = f"Could not import extension {source.path}"
        raise ExtensionError(msg)
    module = importlib.util.module_from_spec(spec)
    sys.modules[name] = module
    try:
        spec.loader.exec_module(module)
    except (KeyboardInterrupt, SystemExit, Exception) as exc:
        sys.modules.pop(name, None)
        if isinstance(exc, KeyboardInterrupt):
            raise
        msg = (
            f"Extension import in {source.path} attempted to exit: {exc}"
            if isinstance(exc, SystemExit)
            else f"Failed to import {source.path}: {exc}"
        )
        raise ExtensionError(msg) from exc
    factory = getattr(module, "extension", None)
    if not callable(factory):
        sys.modules.pop(name, None)
        msg = f"{source.path} does not define a callable 'extension' factory"

View on GitHub (pinned to a1af029e6e)

Solutions

1. Verify the file exists at the printed path and fix or remove the stale configuration entry
2. Check file permissions so the loader can read the extension file
3. Ensure the path points to a real .py file (or package directory) that Python can load
4. Re-add the extension from its current location

Example fix

// before
~/.deepagents/extensions/old_name.py   # deleted

// after
mv new_name.py ~/.deepagents/extensions/old_name.py  # or update config to new path

from pathlib import Path

def extension_file_loadable(path: str | Path) -> bool:
    p = Path(path)
    return p.is_file() and p.suffix == ".py" and p.stat().st_size > 0 and os.access(p, os.R_OK)

try:
    load_extension(source)
except ExtensionError as exc:
    logger.error("cannot load extension at %s: %s", source.path, exc)

When it happens

Trigger: Loading a file-based extension whose path does not exist, was deleted/moved, has a syntax-level unreadable layout, or whose spec cannot be constructed (e.g. bad extension of the file or missing parent directory).

Common situations: Configured an extensions directory path that no longer exists; renamed extension files without updating configuration; permissions preventing module creation; pointing the loader at non-Python files.

Related errors

• Extension import in {source.path} attempted to exit: {exc}
• Failed to import {source.path}: {exc}
• Entry point {entry.name!r} does not resolve to a Python modu
• Profile module not found: {profiles_path}
• Error: Source agent '{source_agent}' not found or has no AGE

AI-assisted analysis of langchain-ai/deepagents@a1af029e6e (2026-08-29). Data as JSON: /api/errors/1f40f62310d508b7. Report an issue: GitHub.