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

# `fastmcp.settings`

## Classes

### `ExtendedEnvSettingsSource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L27" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></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#L34" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></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#L54" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

### `ExperimentalSettings` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L58" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

### `Settings` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L77" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


FastMCP settings.


**Methods:**

#### `get_setting` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L89" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
get_setting(self, attr: str) -> Any
```

Get a setting. If the setting contains one or more `__`, it will be
treated as a nested setting.


#### `set_setting` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L102" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
set_setting(self, attr: str, value: Any) -> None
```

Set a setting. If the setting contains one or more `__`, it will be
treated as a nested setting.


#### `settings_customise_sources` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L116" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></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#L134" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

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


#### `normalize_log_level` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/settings.py#L154" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
normalize_log_level(cls, v)
```
