docs/python-sdk/fastmcp-settings.mdx

---
title: settings
sidebarTitle: settings
---

# `fastmcp.settings`

## Classes

### `ExtendedEnvSettingsSource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L26"><Icon icon="github" size="14" /></a></sup>


A special EnvSettingsSource that allows for multiple env var prefixes to be used.

Raises a deprecation warning if the old `FASTMCP_SERVER_` prefix is used.


**Methods:**

#### `get_field_value` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L33"><Icon icon="github" size="14" /></a></sup>

```python
get_field_value(self, field: FieldInfo, field_name: str) -> tuple[Any, str, bool]
```

### `ExtendedSettingsConfigDict` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L53"><Icon icon="github" size="14" /></a></sup>

### `Settings` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L57"><Icon icon="github" size="14" /></a></sup>


FastMCP settings.


**Methods:**

#### `settings_customise_sources` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L69"><Icon icon="github" size="14" /></a></sup>

```python
settings_customise_sources(cls, settings_cls: type[BaseSettings], init_settings: PydanticBaseSettingsSource, env_settings: PydanticBaseSettingsSource, dotenv_settings: PydanticBaseSettingsSource, file_secret_settings: PydanticBaseSettingsSource) -> tuple[PydanticBaseSettingsSource, ...]
```

#### `settings` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L87"><Icon icon="github" size="14" /></a></sup>

```python
settings(self) -> Self
```

This property is for backwards compatibility with FastMCP < 2.8.0,
which accessed fastmcp.settings.settings


#### `setup_logging` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L182"><Icon icon="github" size="14" /></a></sup>

```python
setup_logging(self) -> Self
```

Finalize the settings.