---
title: base
sidebarTitle: base
---

# `fastmcp.server.providers.base`


Base Provider class for dynamic MCP components.

This module provides the `Provider` abstraction for providing tools,
resources, and prompts dynamically at runtime.

Example:
    ```python
    from fastmcp import FastMCP
    from fastmcp.server.providers import Provider
    from fastmcp.tools import Tool

    class DatabaseProvider(Provider):
        def __init__(self, db_url: str):
            super().__init__()
            self.db = Database(db_url)

        async def list_tools(self) -> list[Tool]:
            rows = await self.db.fetch("SELECT * FROM tools")
            return [self._make_tool(row) for row in rows]

        async def get_tool(self, name: str) -> Tool | None:
            row = await self.db.fetchone("SELECT * FROM tools WHERE name = ?", name)
            return self._make_tool(row) if row else None

    mcp = FastMCP("Server", providers=[DatabaseProvider(db_url)])
    ```


## Classes

### `Provider` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L43" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


Base class for dynamic component providers.

Subclass and override whichever methods you need. Default implementations
return empty lists / None, so you only need to implement what your provider
supports.


**Methods:**

#### `with_transforms` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L67" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
with_transforms(self) -> Provider
```

Apply transformations to this provider's components.

Returns a TransformingProvider that wraps this provider and applies
the specified transformations. Can be chained - each call creates a
new wrapper that composes with the previous.

**Args:**
- `namespace`: Prefix for tools/prompts ("namespace_name"), path segment
for resources ("protocol\://namespace/path").
- `tool_renames`: Map of original_name → final_name. Tools in this map
use the specified name instead of namespace prefixing.

**Returns:**
- A TransformingProvider wrapping this provider.


#### `with_namespace` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L118" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
with_namespace(self, namespace: str) -> Provider
```

Shorthand for with_transforms(namespace=...).

**Args:**
- `namespace`: The namespace to apply.

**Returns:**
- A TransformingProvider wrapping this provider.


#### `list_tools` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L135" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
list_tools(self) -> Sequence[Tool]
```

Return all available tools.

Override to provide tools dynamically.


#### `get_tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L142" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
get_tool(self, name: str) -> Tool | None
```

Get a specific tool by name.

Default implementation lists all tools and finds by name.
Override for more efficient single-tool lookup.

**Returns:**
- The Tool if found, or None to continue searching other providers.


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

```python
list_resources(self) -> Sequence[Resource]
```

Return all available resources.

Override to provide resources dynamically.


#### `get_resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L161" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
get_resource(self, uri: str) -> Resource | None
```

Get a specific resource by URI.

Default implementation lists all resources and finds by URI.
Override for more efficient single-resource lookup.

**Returns:**
- The Resource if found, or None to continue searching other providers.


#### `list_resource_templates` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L173" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
list_resource_templates(self) -> Sequence[ResourceTemplate]
```

Return all available resource templates.

Override to provide resource templates dynamically.


#### `get_resource_template` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L180" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
get_resource_template(self, uri: str) -> ResourceTemplate | None
```

Get a resource template that matches the given URI.

Default implementation lists all templates and finds one whose pattern
matches the URI.
Override for more efficient lookup.

**Returns:**
- The ResourceTemplate if a matching one is found, or None to continue searching.


#### `list_prompts` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L196" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
list_prompts(self) -> Sequence[Prompt]
```

Return all available prompts.

Override to provide prompts dynamically.


#### `get_prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L203" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
get_prompt(self, name: str) -> Prompt | None
```

Get a specific prompt by name.

Default implementation lists all prompts and finds by name.
Override for more efficient single-prompt lookup.

**Returns:**
- The Prompt if found, or None to continue searching other providers.


#### `get_component` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L215" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
get_component(self, key: str) -> Tool | Resource | ResourceTemplate | Prompt | None
```

Get a component by its prefixed key.

**Args:**
- `key`: The prefixed key (e.g., "tool\:name", "resource\:uri", "template\:uri").

**Returns:**
- The component if found, or None to continue searching other providers.


#### `get_tasks` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L244" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
get_tasks(self) -> Sequence[FastMCPComponent]
```

Return components that should be registered as background tasks.

Override to customize which components are task-eligible.
Default calls list_* methods and filters for components
with task_config.mode != 'forbidden'.

Used by the server during startup to register functions with Docket.


#### `lifespan` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L272" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
lifespan(self) -> AsyncIterator[None]
```

User-overridable lifespan for custom setup and teardown.

Override this method to perform provider-specific initialization
like opening database connections, setting up external resources,
or other state management needed for the provider's lifetime.

The lifespan scope matches the server's lifespan - code before yield
runs at startup, code after yield runs at shutdown.


#### `enable` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L301" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
enable(self) -> None
```

Enable components by removing from blocklist, or set allowlist with only=True.

**Args:**
- `keys`: Keys to enable (e.g., "tool\:my_tool").
- `tags`: Tags to enable - components with these tags will be enabled.
- `only`: If True, switches to allowlist mode - ONLY show these keys/tags.


#### `disable` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/providers/base.py#L317" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
disable(self) -> None
```

Disable components by adding to the blocklist.

**Args:**
- `keys`: Keys to disable (e.g., "tool\:my_tool").
- `tags`: Tags to disable - components with these tags will be disabled.

