langchain-ai/deepagents · error · ModelConfigError

Provider package '{package}' is installed but failed to impo

Error message

Provider package '{package}' is installed but failed to import for provider '{provider}': {e}

What it means

Raised as `ModelConfigError` when the provider's LangChain package IS installed (confirmed via `find_spec`) but an ImportError still escaped from `init_chat_model` — meaning an internal import inside the package failed (broken or incompatible dependency). The library deliberately surfaces the real error instead of the misleading 'missing package' hint.

Source

Thrown at libs/code/deepagents_code/config.py:5500

            hint = resolve_install_hint(package)
            if hint.extra is not None:
                msg = (
                    f"Missing package for provider '{provider}'. "
                    f"Install: /install {hint.extra}"
                )
            else:
                if hint.command is not None:
                    install_hint = f"Install with: {hint.command}"
                else:
                    install_hint = f"Install the '{package}' package manually"
                msg = (
                    f"Missing package for provider '{provider}'. "
                    f"{install_hint}, then retry with `/model`."
                )
            raise MissingProviderPackageError(
                msg, provider=provider, package=package
            ) from e
        raise ModelConfigError(msg) from e
    except (ValueError, TypeError) as e:
        if not provider:
            # Both app auto-detection and `init_chat_model`'s own inference
            # failed; surface a structured error so the UI can render the
            # docs URL as a clickable link.
            raise UnknownProviderError(model_spec=model_name) from e
        spec = f"{provider}:{model_name}"
        msg = f"Invalid model configuration for '{spec}': {e}"
        raise ModelConfigError(msg) from e
    except Exception as e:  # provider SDK auth/network errors
        spec = f"{provider}:{model_name}" if provider else model_name
        msg = f"Failed to initialize model '{spec}': {e}"
        raise ModelConfigError(msg) from e


@dataclass(frozen=True)
class ModelResult:
    """Result of creating a chat model, bundling the model with its metadata.

View on GitHub (pinned to a1af029e6e)

Solutions

Read the chained ImportError to identify the failing internal import
Reinstall the package: `pip install --force-reinstall langchain-<provider>`
Align versions (e.g. `pip install -U langchain-core langchain-<provider>`) so the integration matches the installed core

Example fix

// before
ModelConfigError: Provider package 'langchain-anthropic' is installed but failed to import...: No module named 'anthropic._client'

// after
$ pip install --force-reinstall --upgrade langchain-anthropic anthropic
$ dcode -m anthropic:claude-opus-5

Defensive patterns

Strategy: try-catch

Validate before calling

import importlib

def package_imports_cleanly(package: str) -> bool:
    module_name = package.replace("-", "_")
    try:
        importlib.import_module(module_name)
        return True
    except ImportError:
        return False

Try / catch

from deepagents_code.model_config import ModelConfigError
try:
    model = create_model(spec)
except ModelConfigError as e:
    if "installed but failed to import" in str(e):
        logger.error("Broken provider install: %s", e.__cause__)
        raise SystemExit("Run: pip install --force-reinstall -U " + pkg)
    raise

Prevention

Keep langchain-core and langchain-<provider> versions aligned; upgrade together
Use a lock file so partial upgrades cannot corrupt the environment
Run a smoke `import langchain_<provider>` check at image-build time

When it happens

Trigger: `init_chat_model` raises ImportError for a provider, but `importlib.util.find_spec(package.replace('-', '_'))` is not None, so the code takes the 'installed but failed to import' branch in `_create_model_via_init` (config.py:5460-5478, raise at 5500).

Common situations: Partially installed or corrupted package; version conflict between `langchain-<provider>` and `langchain-core` after a partial upgrade; a broken transitive dependency; leftover files from a failed uninstall.

Related errors

AI-assisted analysis of langchain-ai/deepagents@a1af029e6e (2026-08-29). Data as JSON: /api/errors/d18602e2b9aac4ed. Report an issue: GitHub.