# resolve_headers

> **Function** in `deepagents_code`

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

Resolve `${VAR}` env-var references in header values.

## Signature

```python
resolve_headers(
    headers: dict[str, str],
    *,
    server_name: str | None = None,
) -> dict[str, str]
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `headers` | `dict[str, str]` | Yes | Raw header mapping from MCP config. |
| `server_name` | `str \| None` | No | Optional server name for error messages. (default: `None`) |

## Returns

`dict[str, str]`

A new dict with env-var references resolved to current values.

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[View source on GitHub](https://github.com/langchain-ai/deepagents/blob/0412009c5441bef8d75a427e1da8909e33ab5b56/libs/code/deepagents_code/mcp_auth.py#L134)