# get_credential_env_var

> **Function** in `deepagents_code`

📖 [View in docs](https://reference.langchain.com/python/deepagents-code/model_config/get_credential_env_var)

Return the env var name that holds credentials for a provider.

Checks the config file first (user override), then falls back to the
hardcoded `PROVIDER_API_KEY_ENV` map.

## Signature

```python
get_credential_env_var(
    provider: str,
) -> str | None
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `provider` | `str` | Yes | Provider name. |

## Returns

`str | None`

Environment variable name, or None if unknown.

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[View source on GitHub](https://github.com/langchain-ai/deepagents/blob/1f5aa621cce7d89395d2db1533f81a299d059a7a/libs/code/deepagents_code/model_config.py#L1748)