fastmcp/docs/python-sdk/fastmcp-server-server.mdx

---
title: server
sidebarTitle: server
---

# `fastmcp.server.server`


FastMCP - A more ergonomic interface for MCP servers.

## Functions

### `default_lifespan` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L239" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
default_lifespan(server: FastMCP[LifespanResultT]) -> AsyncIterator[Any]
```


Default lifespan context manager that does nothing.

**Args:**
- `server`: The server instance this lifespan is managing

**Returns:**
- An empty dictionary as the lifespan result.


### `create_proxy` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2983" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
create_proxy(target: Client[ClientTransportT] | ClientTransport | FastMCP[Any] | FastMCP1Server | AnyUrl | Path | MCPConfig | dict[str, Any] | str, **settings: Any) -> FastMCPProxy
```


Create a FastMCP proxy server for the given target.

This is the recommended way to create a proxy server. For lower-level control,
use `FastMCPProxy` or `ProxyProvider` directly from `fastmcp.server.providers.proxy`.

**Args:**
- `target`: The backend to proxy to. Can be\:
- A Client instance (connected or disconnected)
- A ClientTransport
- A FastMCP server instance
- A URL string or AnyUrl
- A Path to a server script
- An MCPConfig or dict
- `**settings`: Additional settings passed to FastMCPProxy (name, etc.)

**Returns:**
- A FastMCPProxy server that proxies to the target.


## Classes

### `StateValue` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L295" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


Wrapper for stored context state values.


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

**Methods:**

#### `settings` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L534" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `name` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L545" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
name(self) -> str
```

#### `instructions` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L549" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
instructions(self) -> str | None
```

#### `instructions` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L553" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
instructions(self, value: str | None) -> None
```

#### `version` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L557" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
version(self) -> str | None
```

#### `website_url` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L561" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
website_url(self) -> str | None
```

#### `icons` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L565" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
icons(self) -> list[mcp.types.Icon]
```

#### `docket` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L572" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
docket(self) -> Docket | None
```

Get the Docket instance if Docket support is enabled.

Returns None if Docket is not enabled or server hasn't been started yet.


#### `run_async` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L704" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
run_async(self, transport: Transport | None = None, show_banner: bool | None = None, **transport_kwargs: Any) -> None
```

Run the FastMCP server asynchronously.

**Args:**
- `transport`: Transport protocol to use ("stdio", "sse", or "streamable-http")
- `show_banner`: Whether to display the server banner. If None, uses the
FASTMCP_SHOW_SERVER_BANNER setting (default\: True).


#### `run` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L738" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
run(self, transport: Transport | None = None, show_banner: bool | None = None, **transport_kwargs: Any) -> None
```

Run the FastMCP server. Note this is a synchronous function.

**Args:**
- `transport`: Transport protocol to use ("http", "stdio", "sse", or "streamable-http")
- `show_banner`: Whether to display the server banner. If None, uses the
FASTMCP_SHOW_SERVER_BANNER setting (default\: True).


#### `add_middleware` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L876" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_middleware(self, middleware: Middleware) -> None
```

#### `add_provider` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L879" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_provider(self, provider: Provider) -> None
```

Add a provider for dynamic tools, resources, and prompts.

Providers are queried in registration order. The first provider to return
a non-None result wins. Static components (registered via decorators)
always take precedence over providers.

**Args:**
- `provider`: A Provider instance that will provide components dynamically.
- `namespace`: Optional namespace prefix. When set\:
- Tools become "namespace_toolname"
- Resources become "protocol\://namespace/path"
- Prompts become "namespace_promptname"


#### `get_tasks` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L901" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Get task-eligible components with all transforms applied.

Overrides AggregateProvider.get_tasks() to apply server-level transforms
after aggregation. AggregateProvider handles provider-level namespacing.


#### `add_transform` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L956" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_transform(self, transform: Transform) -> None
```

Add a server-level transform.

Server-level transforms are applied after all providers are aggregated.
They transform tools, resources, and prompts from ALL providers.

**Args:**
- `transform`: The transform to add.


#### `add_tool_transformation` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L976" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_tool_transformation(self, tool_name: str, transformation: ToolTransformConfig) -> None
```

Add a tool transformation.

.. deprecated::
    Use ``add_transform(ToolTransform({...}))`` instead.


#### `remove_tool_transformation` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L993" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
remove_tool_transformation(self, _tool_name: str) -> None
```

Remove a tool transformation.

.. deprecated::
    Tool transformations are now immutable. Use enable/disable controls instead.


#### `list_tools` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1008" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

List all enabled tools from providers.

Overrides Provider.list_tools() to add enabled filtering, auth filtering,
and middleware execution. Returns all versions (no deduplication).
Protocol handlers deduplicate for MCP wire format.


#### `get_tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1078" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Get a tool by name, filtering disabled tools.

Overrides Provider.get_tool() to add enabled filtering after all
transforms (including session-level) have been applied. This ensures
session transforms can override provider-level disables.

**Args:**
- `name`: The tool name.
- `version`: Version filter (None returns highest version).

**Returns:**
- The tool if found and enabled, None otherwise.


#### `list_resources` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1104" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

List all enabled resources from providers.

Overrides Provider.list_resources() to add enabled filtering, auth filtering,
and middleware execution. Returns all versions (no deduplication).
Protocol handlers deduplicate for MCP wire format.


#### `get_resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1176" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Get a resource by URI, filtering disabled resources.

Overrides Provider.get_resource() to add enabled filtering after all
transforms (including session-level) have been applied.

**Args:**
- `uri`: The resource URI.
- `version`: Version filter (None returns highest version).

**Returns:**
- The resource if found and enabled, None otherwise.


#### `list_resource_templates` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1201" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

List all enabled resource templates from providers.

Overrides Provider.list_resource_templates() to add enabled filtering,
auth filtering, and middleware execution. Returns all versions (no deduplication).
Protocol handlers deduplicate for MCP wire format.


#### `get_resource_template` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1275" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Get a resource template by URI, filtering disabled templates.

Overrides Provider.get_resource_template() to add enabled filtering after
all transforms (including session-level) have been applied.

**Args:**
- `uri`: The template URI.
- `version`: Version filter (None returns highest version).

**Returns:**
- The template if found and enabled, None otherwise.


#### `list_prompts` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1300" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

List all enabled prompts from providers.

Overrides Provider.list_prompts() to add enabled filtering, auth filtering,
and middleware execution. Returns all versions (no deduplication).
Protocol handlers deduplicate for MCP wire format.


#### `get_prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1370" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Get a prompt by name, filtering disabled prompts.

Overrides Provider.get_prompt() to add enabled filtering after all
transforms (including session-level) have been applied.

**Args:**
- `name`: The prompt name.
- `version`: Version filter (None returns highest version).

**Returns:**
- The prompt if found and enabled, None otherwise.


#### `call_tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1396" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
call_tool(self, name: str, arguments: dict[str, Any] | None = None) -> ToolResult
```

#### `call_tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1407" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
call_tool(self, name: str, arguments: dict[str, Any] | None = None) -> mcp.types.CreateTaskResult
```

#### `call_tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1417" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
call_tool(self, name: str, arguments: dict[str, Any] | None = None) -> ToolResult | mcp.types.CreateTaskResult
```

Call a tool by name.

This is the public API for executing tools. By default, middleware is applied.

**Args:**
- `name`: The tool name
- `arguments`: Tool arguments (optional)
- `version`: Specific version to call. If None, calls highest version.
- `run_middleware`: If True (default), apply the middleware chain.
Set to False when called from middleware to avoid re-applying.
- `task_meta`: If provided, execute as a background task and return
CreateTaskResult. If None (default), execute synchronously and
return ToolResult.

**Returns:**
- ToolResult when task_meta is None.
- CreateTaskResult when task_meta is provided.

**Raises:**
- `NotFoundError`: If tool not found or disabled
- `ToolError`: If tool execution fails
- `ValidationError`: If arguments fail validation


#### `read_resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1501" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
read_resource(self, uri: str) -> ResourceResult
```

#### `read_resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1511" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
read_resource(self, uri: str) -> mcp.types.CreateTaskResult
```

#### `read_resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1520" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
read_resource(self, uri: str) -> ResourceResult | mcp.types.CreateTaskResult
```

Read a resource by URI.

This is the public API for reading resources. By default, middleware is applied.
Checks concrete resources first, then templates.

**Args:**
- `uri`: The resource URI
- `version`: Specific version to read. If None, reads highest version.
- `run_middleware`: If True (default), apply the middleware chain.
Set to False when called from middleware to avoid re-applying.
- `task_meta`: If provided, execute as a background task and return
CreateTaskResult. If None (default), execute synchronously and
return ResourceResult.

**Returns:**
- ResourceResult when task_meta is None.
- CreateTaskResult when task_meta is provided.

**Raises:**
- `NotFoundError`: If resource not found or disabled
- `ResourceError`: If resource read fails


#### `render_prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1632" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
render_prompt(self, name: str, arguments: dict[str, Any] | None = None) -> PromptResult
```

#### `render_prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1643" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
render_prompt(self, name: str, arguments: dict[str, Any] | None = None) -> mcp.types.CreateTaskResult
```

#### `render_prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1653" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
render_prompt(self, name: str, arguments: dict[str, Any] | None = None) -> PromptResult | mcp.types.CreateTaskResult
```

Render a prompt by name.

This is the public API for rendering prompts. By default, middleware is applied.
Use get_prompt() to retrieve the prompt definition without rendering.

**Args:**
- `name`: The prompt name
- `arguments`: Prompt arguments (optional)
- `version`: Specific version to render. If None, renders highest version.
- `run_middleware`: If True (default), apply the middleware chain.
Set to False when called from middleware to avoid re-applying.
- `task_meta`: If provided, execute as a background task and return
CreateTaskResult. If None (default), execute synchronously and
return PromptResult.

**Returns:**
- PromptResult when task_meta is None.
- CreateTaskResult when task_meta is provided.

**Raises:**
- `NotFoundError`: If prompt not found or disabled
- `PromptError`: If prompt rendering fails


#### `custom_route` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L1729" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
custom_route(self, path: str, methods: list[str], name: str | None = None, include_in_schema: bool = True) -> Callable[[Callable[[Request], Awaitable[Response]]], Callable[[Request], Awaitable[Response]]]
```

Decorator to register a custom HTTP route on the FastMCP server.

Allows adding arbitrary HTTP endpoints outside the standard MCP protocol,
which can be useful for OAuth callbacks, health checks, or admin APIs.
The handler function must be an async function that accepts a Starlette
Request and returns a Response.

**Args:**
- `path`: URL path for the route (e.g., "/auth/callback")
- `methods`: List of HTTP methods to support (e.g., ["GET", "POST"])
- `name`: Optional name for the route (to reference this route with
Starlette's reverse URL lookup feature)
- `include_in_schema`: Whether to include in OpenAPI schema, defaults to True


#### `add_tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2032" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_tool(self, tool: Tool | Callable[..., Any]) -> Tool
```

Add a tool to the server.

The tool function can optionally request a Context object by adding a parameter
with the Context type annotation. See the @tool decorator for examples.

**Args:**
- `tool`: The Tool instance or @tool-decorated function to register

**Returns:**
- The tool instance that was added to the server.


#### `remove_tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2046" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
remove_tool(self, name: str, version: str | None = None) -> None
```

Remove tool(s) from the server.

**Args:**
- `name`: The name of the tool to remove.
- `version`: If None, removes ALL versions. If specified, removes only that version.

**Raises:**
- `NotFoundError`: If no matching tool is found.


#### `tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2066" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
tool(self, name_or_fn: AnyFunction) -> FunctionTool
```

#### `tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2086" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
tool(self, name_or_fn: str | None = None) -> Callable[[AnyFunction], FunctionTool]
```

#### `tool` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2105" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
tool(self, name_or_fn: str | AnyFunction | None = None) -> Callable[[AnyFunction], FunctionTool] | FunctionTool | partial[Callable[[AnyFunction], FunctionTool] | FunctionTool]
```

Decorator to register a tool.

Tools can optionally request a Context object by adding a parameter with the
Context type annotation. The context provides access to MCP capabilities like
logging, progress reporting, and resource access.

This decorator supports multiple calling patterns:
- @server.tool (without parentheses)
- @server.tool (with empty parentheses)
- @server.tool("custom_name") (with name as first argument)
- @server.tool(name="custom_name") (with name as keyword argument)
- server.tool(function, name="custom_name") (direct function call)

**Args:**
- `name_or_fn`: Either a function (when used as @tool), a string name, or None
- `name`: Optional name for the tool (keyword-only, alternative to name_or_fn)
- `description`: Optional description of what the tool does
- `tags`: Optional set of tags for categorizing the tool
- `output_schema`: Optional JSON schema for the tool's output
- `annotations`: Optional annotations about the tool's behavior
- `exclude_args`: Optional list of argument names to exclude from the tool schema.
Deprecated\: Use `Depends()` for dependency injection instead.
- `meta`: Optional meta information about the tool

**Examples:**

Register a tool with a custom name:
```python
@server.tool
def my_tool(x: int) -> str:
    return str(x)

# Register a tool with a custom name
@server.tool
def my_tool(x: int) -> str:
    return str(x)

@server.tool("custom_name")
def my_tool(x: int) -> str:
    return str(x)

@server.tool(name="custom_name")
def my_tool(x: int) -> str:
    return str(x)

# Direct function call
server.tool(my_function, name="custom_name")
```


#### `add_resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2196" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_resource(self, resource: Resource | Callable[..., Any]) -> Resource | ResourceTemplate
```

Add a resource to the server.

**Args:**
- `resource`: A Resource instance or @resource-decorated function to add

**Returns:**
- The resource instance that was added to the server.


#### `add_template` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2209" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_template(self, template: ResourceTemplate) -> ResourceTemplate
```

Add a resource template to the server.

**Args:**
- `template`: A ResourceTemplate instance to add

**Returns:**
- The template instance that was added to the server.


#### `resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2220" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
resource(self, uri: str) -> Callable[[AnyFunction], Resource | ResourceTemplate | AnyFunction]
```

Decorator to register a function as a resource.

The function will be called when the resource is read to generate its content.
The function can return:
- str for text content
- bytes for binary content
- other types will be converted to JSON

Resources can optionally request a Context object by adding a parameter with the
Context type annotation. The context provides access to MCP capabilities like
logging, progress reporting, and session information.

If the URI contains parameters (e.g. "resource://{param}") or the function
has parameters, it will be registered as a template resource.

**Args:**
- `uri`: URI for the resource (e.g. "resource\://my-resource" or "resource\://{param}")
- `name`: Optional name for the resource
- `description`: Optional description of the resource
- `mime_type`: Optional MIME type for the resource
- `tags`: Optional set of tags for categorizing the resource
- `annotations`: Optional annotations about the resource's behavior
- `meta`: Optional meta information about the resource

**Examples:**

Register a resource with a custom name:
```python
@server.resource("resource://my-resource")
def get_data() -> str:
    return "Hello, world!"

@server.resource("resource://my-resource")
async get_data() -> str:
    data = await fetch_data()
    return f"Hello, world! {data}"

@server.resource("resource://{city}/weather")
def get_weather(city: str) -> str:
    return f"Weather for {city}"

@server.resource("resource://{city}/weather")
async def get_weather_with_context(city: str, ctx: Context) -> str:
    await ctx.info(f"Fetching weather for {city}")
    return f"Weather for {city}"

@server.resource("resource://{city}/weather")
async def get_weather(city: str) -> str:
    data = await fetch_weather(city)
    return f"Weather for {city}: {data}"
```


#### `add_prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2308" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_prompt(self, prompt: Prompt | Callable[..., Any]) -> Prompt
```

Add a prompt to the server.

**Args:**
- `prompt`: A Prompt instance or @prompt-decorated function to add

**Returns:**
- The prompt instance that was added to the server.


#### `prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2320" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
prompt(self, name_or_fn: AnyFunction) -> FunctionPrompt
```

#### `prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2336" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
prompt(self, name_or_fn: str | None = None) -> Callable[[AnyFunction], FunctionPrompt]
```

#### `prompt` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2351" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
prompt(self, name_or_fn: str | AnyFunction | None = None) -> Callable[[AnyFunction], FunctionPrompt] | FunctionPrompt | partial[Callable[[AnyFunction], FunctionPrompt] | FunctionPrompt]
```

Decorator to register a prompt.

        Prompts can optionally request a Context object by adding a parameter with the
        Context type annotation. The context provides access to MCP capabilities like
        logging, progress reporting, and session information.

        This decorator supports multiple calling patterns:
        - @server.prompt (without parentheses)
        - @server.prompt() (with empty parentheses)
        - @server.prompt("custom_name") (with name as first argument)
        - @server.prompt(name="custom_name") (with name as keyword argument)
        - server.prompt(function, name="custom_name") (direct function call)

        Args:
            name_or_fn: Either a function (when used as @prompt), a string name, or None
            name: Optional name for the prompt (keyword-only, alternative to name_or_fn)
            description: Optional description of what the prompt does
            tags: Optional set of tags for categorizing the prompt
            meta: Optional meta information about the prompt

        Examples:

            ```python
            @server.prompt
            def analyze_table(table_name: str) -> list[Message]:
                schema = read_table_schema(table_name)
                return [
                    {
                        "role": "user",
                        "content": f"Analyze this schema:
{schema}"
                    }
                ]

            @server.prompt()
            async def analyze_with_context(table_name: str, ctx: Context) -> list[Message]:
                await ctx.info(f"Analyzing table {table_name}")
                schema = read_table_schema(table_name)
                return [
                    {
                        "role": "user",
                        "content": f"Analyze this schema:
{schema}"
                    }
                ]

            @server.prompt("custom_name")
            async def analyze_file(path: str) -> list[Message]:
                content = await read_file(path)
                return [
                    {
                        "role": "user",
                        "content": {
                            "type": "resource",
                            "resource": {
                                "uri": f"file://{path}",
                                "text": content
                            }
                        }
                    }
                ]

            @server.prompt(name="custom_name")
            def another_prompt(data: str) -> list[Message]:
                return [{"role": "user", "content": data}]

            # Direct function call
            server.prompt(my_function, name="custom_name")
            ```


#### `run_stdio_async` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2451" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
run_stdio_async(self, show_banner: bool = True, log_level: str | None = None, stateless: bool = False) -> None
```

Run the server using stdio transport.

**Args:**
- `show_banner`: Whether to display the server banner
- `log_level`: Log level for the server
- `stateless`: Whether to run in stateless mode (no session initialization)


#### `run_http_async` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2493" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
run_http_async(self, show_banner: bool = True, transport: Literal['http', 'streamable-http', 'sse'] = 'http', host: str | None = None, port: int | None = None, log_level: str | None = None, path: str | None = None, uvicorn_config: dict[str, Any] | None = None, middleware: list[ASGIMiddleware] | None = None, json_response: bool | None = None, stateless_http: bool | None = None, stateless: bool | None = None) -> None
```

Run the server using HTTP transport.

**Args:**
- `transport`: Transport protocol to use - either "streamable-http" (default) or "sse"
- `host`: Host address to bind to (defaults to settings.host)
- `port`: Port to bind to (defaults to settings.port)
- `log_level`: Log level for the server (defaults to settings.log_level)
- `path`: Path for the endpoint (defaults to settings.streamable_http_path or settings.sse_path)
- `uvicorn_config`: Additional configuration for the Uvicorn server
- `middleware`: A list of middleware to apply to the app
- `json_response`: Whether to use JSON response format (defaults to settings.json_response)
- `stateless_http`: Whether to use stateless HTTP (defaults to settings.stateless_http)
- `stateless`: Alias for stateless_http for CLI consistency


#### `http_app` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2574" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
http_app(self, path: str | None = None, middleware: list[ASGIMiddleware] | None = None, json_response: bool | None = None, stateless_http: bool | None = None, transport: Literal['http', 'streamable-http', 'sse'] = 'http', event_store: EventStore | None = None, retry_interval: int | None = None) -> StarletteWithLifespan
```

Create a Starlette app using the specified HTTP transport.

**Args:**
- `path`: The path for the HTTP endpoint
- `middleware`: A list of middleware to apply to the app
- `json_response`: Whether to use JSON response format
- `stateless_http`: Whether to use stateless mode (new transport per request)
- `transport`: Transport protocol to use - "http", "streamable-http", or "sse"
- `event_store`: Optional event store for SSE polling/resumability. When set,
enables clients to reconnect and resume receiving events after
server-initiated disconnections. Only used with streamable-http transport.
- `retry_interval`: Optional retry interval in milliseconds for SSE polling.
Controls how quickly clients should reconnect after server-initiated
disconnections. Requires event_store to be set. Only used with
streamable-http transport.

**Returns:**
- A Starlette application configured with the specified transport


#### `mount` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2635" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
mount(self, server: FastMCP[LifespanResultT], namespace: str | None = None, as_proxy: bool | None = None, tool_names: dict[str, str] | None = None, prefix: str | None = None) -> None
```

Mount another FastMCP server on this server with an optional namespace.

Unlike importing (with import_server), mounting establishes a dynamic connection
between servers. When a client interacts with a mounted server's objects through
the parent server, requests are forwarded to the mounted server in real-time.
This means changes to the mounted server are immediately reflected when accessed
through the parent.

When a server is mounted with a namespace:
- Tools from the mounted server are accessible with namespaced names.
  Example: If server has a tool named "get_weather", it will be available as "namespace_get_weather".
- Resources are accessible with namespaced URIs.
  Example: If server has a resource with URI "weather://forecast", it will be available as
  "weather://namespace/forecast".
- Templates are accessible with namespaced URI templates.
  Example: If server has a template with URI "weather://location/{id}", it will be available
  as "weather://namespace/location/{id}".
- Prompts are accessible with namespaced names.
  Example: If server has a prompt named "weather_prompt", it will be available as
  "namespace_weather_prompt".

When a server is mounted without a namespace (namespace=None), its tools, resources, templates,
and prompts are accessible with their original names. Multiple servers can be mounted
without namespaces, and they will be tried in order until a match is found.

The mounted server's lifespan is executed when the parent server starts, and its
middleware chain is invoked for all operations (tool calls, resource reads, prompts).

**Args:**
- `server`: The FastMCP server to mount.
- `namespace`: Optional namespace to use for the mounted server's objects. If None,
the server's objects are accessible with their original names.
- `as_proxy`: Deprecated. Mounted servers now always have their lifespan and
middleware invoked. To create a proxy server, use create_proxy()
explicitly before mounting.
- `tool_names`: Optional mapping of original tool names to custom names. Use this
to override namespaced names. Keys are the original tool names from the
mounted server.
- `prefix`: Deprecated. Use namespace instead.


#### `import_server` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2729" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
import_server(self, server: FastMCP[LifespanResultT], prefix: str | None = None) -> None
```

Import the MCP objects from another FastMCP server into this one,
optionally with a given prefix.

.. deprecated::
    Use :meth:`mount` instead. ``import_server`` will be removed in a
    future version.

Note that when a server is *imported*, its objects are immediately
registered to the importing server. This is a one-time operation and
future changes to the imported server will not be reflected in the
importing server. Server-level configurations and lifespans are not imported.

When a server is imported with a prefix:
- The tools are imported with prefixed names
  Example: If server has a tool named "get_weather", it will be
  available as "prefix_get_weather"
- The resources are imported with prefixed URIs using the new format
  Example: If server has a resource with URI "weather://forecast", it will
  be available as "weather://prefix/forecast"
- The templates are imported with prefixed URI templates using the new format
  Example: If server has a template with URI "weather://location/{id}", it will
  be available as "weather://prefix/location/{id}"
- The prompts are imported with prefixed names
  Example: If server has a prompt named "weather_prompt", it will be available as
  "prefix_weather_prompt"

When a server is imported without a prefix (prefix=None), its tools, resources,
templates, and prompts are imported with their original names.

**Args:**
- `server`: The FastMCP server to import
- `prefix`: Optional prefix to use for the imported server's objects. If None,
objects are imported with their original names.


#### `from_openapi` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2829" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
from_openapi(cls, openapi_spec: dict[str, Any], client: httpx.AsyncClient, name: str = 'OpenAPI Server', route_maps: list[RouteMap] | None = None, route_map_fn: OpenAPIRouteMapFn | None = None, mcp_component_fn: OpenAPIComponentFn | None = None, mcp_names: dict[str, str] | None = None, tags: set[str] | None = None, timeout: float | None = None, **settings: Any) -> Self
```

Create a FastMCP server from an OpenAPI specification.

**Args:**
- `openapi_spec`: OpenAPI schema as a dictionary
- `client`: httpx AsyncClient for making HTTP requests
- `name`: Name for the MCP server
- `route_maps`: Optional list of RouteMap objects defining route mappings
- `route_map_fn`: Optional callable for advanced route type mapping
- `mcp_component_fn`: Optional callable for component customization
- `mcp_names`: Optional dictionary mapping operationId to component names
- `tags`: Optional set of tags to add to all components
- `timeout`: Optional timeout (in seconds) for all requests
- `**settings`: Additional settings passed to FastMCP

**Returns:**
- A FastMCP server with an OpenAPIProvider attached.


#### `from_fastapi` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2875" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
from_fastapi(cls, app: Any, name: str | None = None, route_maps: list[RouteMap] | None = None, route_map_fn: OpenAPIRouteMapFn | None = None, mcp_component_fn: OpenAPIComponentFn | None = None, mcp_names: dict[str, str] | None = None, httpx_client_kwargs: dict[str, Any] | None = None, tags: set[str] | None = None, timeout: float | None = None, **settings: Any) -> Self
```

Create a FastMCP server from a FastAPI application.

**Args:**
- `app`: FastAPI application instance
- `name`: Name for the MCP server (defaults to app.title)
- `route_maps`: Optional list of RouteMap objects defining route mappings
- `route_map_fn`: Optional callable for advanced route type mapping
- `mcp_component_fn`: Optional callable for component customization
- `mcp_names`: Optional dictionary mapping operationId to component names
- `httpx_client_kwargs`: Optional kwargs passed to httpx.AsyncClient
- `tags`: Optional set of tags to add to all components
- `timeout`: Optional timeout (in seconds) for all requests
- `**settings`: Additional settings passed to FastMCP

**Returns:**
- A FastMCP server with an OpenAPIProvider attached.


#### `as_proxy` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2932" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
as_proxy(cls, backend: Client[ClientTransportT] | ClientTransport | FastMCP[Any] | FastMCP1Server | AnyUrl | Path | MCPConfig | dict[str, Any] | str, **settings: Any) -> FastMCPProxy
```

Create a FastMCP proxy server for the given backend.

.. deprecated::
    Use :func:`fastmcp.server.create_proxy` instead.
    This method will be removed in a future version.

The `backend` argument can be either an existing `fastmcp.client.Client`
instance or any value accepted as the `transport` argument of
`fastmcp.client.Client`. This mirrors the convenience of the
`fastmcp.client.Client` constructor.


#### `generate_name` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/server/server.py#L2969" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
generate_name(cls, name: str | None = None) -> str
```