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MCPServer - A more ergonomic interface for MCP servers.

Icon

Bases: MCPModel

An icon for display in user interfaces.

Source code in src/mcp/types/_types.py 
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class Icon(MCPModel):
    """An icon for display in user interfaces."""

    src: str
    """URL or data URI for the icon."""

    mime_type: str | None = None
    """Optional MIME type for the icon."""

    sizes: list[str] | None = None
    """Optional list of strings specifying icon dimensions (e.g., ["48x48", "96x96"])."""

    theme: IconTheme | None = None
    """Optional theme specifier.

    `"light"` indicates the icon is designed for a light background, `"dark"` indicates the icon
    is designed for a dark background.

    See https://modelcontextprotocol.io/specification/2025-11-25/schema#icon for more details.
    """

src instance-attribute 

src: str

URL or data URI for the icon.

mime_type class-attribute instance-attribute 

mime_type: str | None = None

Optional MIME type for the icon.

sizes class-attribute instance-attribute 

sizes: list[str] | None = None

Optional list of strings specifying icon dimensions (e.g., ["48x48", "96x96"]).

theme class-attribute instance-attribute 

theme: IconTheme | None = None

Optional theme specifier.

"light" indicates the icon is designed for a light background, "dark" indicates the icon is designed for a dark background.

See https://modelcontextprotocol.io/specification/2025-11-25/schema#icon for more details.

Context

Bases: BaseModel, Generic[LifespanContextT, RequestT]

Context object providing access to MCP capabilities.

This provides a cleaner interface to MCP's RequestContext functionality. It gets injected into tool and resource functions that request it via type hints.

To use context in a tool function, add a parameter with the Context type annotation:

@server.tool()
async def my_tool(x: int, ctx: Context) -> str:
    # Log messages to the client
    await ctx.info(f"Processing {x}")
    await ctx.debug("Debug info")
    await ctx.warning("Warning message")
    await ctx.error("Error message")

    # Report progress
    await ctx.report_progress(50, 100)

    # Access resources
    data = await ctx.read_resource("resource://data")

    # Get request info
    request_id = ctx.request_id
    client_id = ctx.client_id

    return str(x)

The context parameter name can be anything as long as it's annotated with Context. The context is optional - tools that don't need it can omit the parameter.

Source code in src/mcp/server/mcpserver/context.py 
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class Context(BaseModel, Generic[LifespanContextT, RequestT]):
    """Context object providing access to MCP capabilities.

    This provides a cleaner interface to MCP's RequestContext functionality.
    It gets injected into tool and resource functions that request it via type hints.

    To use context in a tool function, add a parameter with the Context type annotation:

    ```python
    @server.tool()
    async def my_tool(x: int, ctx: Context) -> str:
        # Log messages to the client
        await ctx.info(f"Processing {x}")
        await ctx.debug("Debug info")
        await ctx.warning("Warning message")
        await ctx.error("Error message")

        # Report progress
        await ctx.report_progress(50, 100)

        # Access resources
        data = await ctx.read_resource("resource://data")

        # Get request info
        request_id = ctx.request_id
        client_id = ctx.client_id

        return str(x)
    ```

    The context parameter name can be anything as long as it's annotated with Context.
    The context is optional - tools that don't need it can omit the parameter.
    """

    _request_context: ServerRequestContext[LifespanContextT, RequestT] | None
    _mcp_server: MCPServer | None

    # TODO(maxisbey): Consider making request_context/mcp_server required, or refactor Context entirely.
    def __init__(
        self,
        *,
        request_context: ServerRequestContext[LifespanContextT, RequestT] | None = None,
        mcp_server: MCPServer | None = None,
        # TODO(Marcelo): We should drop this kwargs parameter.
        **kwargs: Any,
    ):
        super().__init__(**kwargs)
        self._request_context = request_context
        self._mcp_server = mcp_server

    @property
    def mcp_server(self) -> MCPServer:
        """Access to the MCPServer instance."""
        if self._mcp_server is None:  # pragma: no cover
            raise ValueError("Context is not available outside of a request")
        return self._mcp_server  # pragma: no cover

    @property
    def request_context(self) -> ServerRequestContext[LifespanContextT, RequestT]:
        """Access to the underlying request context."""
        if self._request_context is None:  # pragma: no cover
            raise ValueError("Context is not available outside of a request")
        return self._request_context

    async def report_progress(self, progress: float, total: float | None = None, message: str | None = None) -> None:
        """Report progress for the current operation.

        Args:
            progress: Current progress value (e.g., 24)
            total: Optional total value (e.g., 100)
            message: Optional message (e.g., "Starting render...")
        """
        progress_token = self.request_context.meta.get("progress_token") if self.request_context.meta else None

        if progress_token is None:  # pragma: no cover
            return

        await self.request_context.session.send_progress_notification(
            progress_token=progress_token,
            progress=progress,
            total=total,
            message=message,
            related_request_id=self.request_id,
        )

    async def read_resource(self, uri: str | AnyUrl) -> Iterable[ReadResourceContents]:
        """Read a resource by URI.

        Args:
            uri: Resource URI to read

        Returns:
            The resource content as either text or bytes
        """
        assert self._mcp_server is not None, "Context is not available outside of a request"
        return await self._mcp_server.read_resource(uri, self)

    async def elicit(
        self,
        message: str,
        schema: type[ElicitSchemaModelT],
    ) -> ElicitationResult[ElicitSchemaModelT]:
        """Elicit information from the client/user.

        This method can be used to interactively ask for additional information from the
        client within a tool's execution. The client might display the message to the
        user and collect a response according to the provided schema. If the client
        is an agent, it might decide how to handle the elicitation -- either by asking
        the user or automatically generating a response.

        Args:
            message: Message to present to the user
            schema: A Pydantic model class defining the expected response structure.
                    According to the specification, only primitive types are allowed.

        Returns:
            An ElicitationResult containing the action taken and the data if accepted

        Note:
            Check the result.action to determine if the user accepted, declined, or cancelled.
            The result.data will only be populated if action is "accept" and validation succeeded.
        """

        return await elicit_with_validation(
            session=self.request_context.session,
            message=message,
            schema=schema,
            related_request_id=self.request_id,
        )

    async def elicit_url(
        self,
        message: str,
        url: str,
        elicitation_id: str,
    ) -> UrlElicitationResult:
        """Request URL mode elicitation from the client.

        This directs the user to an external URL for out-of-band interactions
        that must not pass through the MCP client. Use this for:
        - Collecting sensitive credentials (API keys, passwords)
        - OAuth authorization flows with third-party services
        - Payment and subscription flows
        - Any interaction where data should not pass through the LLM context

        The response indicates whether the user consented to navigate to the URL.
        The actual interaction happens out-of-band. When the elicitation completes,
        call `ctx.session.send_elicit_complete(elicitation_id)` to notify the client.

        Args:
            message: Human-readable explanation of why the interaction is needed
            url: The URL the user should navigate to
            elicitation_id: Unique identifier for tracking this elicitation

        Returns:
            UrlElicitationResult indicating accept, decline, or cancel
        """
        return await elicit_url(
            session=self.request_context.session,
            message=message,
            url=url,
            elicitation_id=elicitation_id,
            related_request_id=self.request_id,
        )

    async def log(
        self,
        level: LoggingLevel,
        data: Any,
        *,
        logger_name: str | None = None,
    ) -> None:
        """Send a log message to the client.

        Args:
            level: Log level (debug, info, notice, warning, error, critical,
                alert, emergency)
            data: The data to be logged. Any JSON serializable type is allowed
                (string, dict, list, number, bool, etc.) per the MCP specification.
            logger_name: Optional logger name
        """
        await self.request_context.session.send_log_message(
            level=level,
            data=data,
            logger=logger_name,
            related_request_id=self.request_id,
        )

    # TODO(maxisbey): see if this is needed otherwise remove
    @property
    def client_id(self) -> str | None:
        """Get the client ID if available.

        Note: this reads from the MCP request's `_meta` params, not the OAuth
        bearer token. For that, use `get_access_token().client_id`.
        """
        return self.request_context.meta.get("client_id") if self.request_context.meta else None  # pragma: no cover

    @property
    def request_id(self) -> str:
        """Get the unique ID for this request."""
        return str(self.request_context.request_id)

    @property
    def session(self):
        """Access to the underlying session for advanced usage."""
        return self.request_context.session

    async def close_sse_stream(self) -> None:
        """Close the SSE stream to trigger client reconnection.

        This method closes the HTTP connection for the current request, triggering
        client reconnection. Events continue to be stored in the event store and will
        be replayed when the client reconnects with Last-Event-ID.

        Use this to implement polling behavior during long-running operations -
        the client will reconnect after the retry interval specified in the priming event.

        Note:
            This is a no-op if not using StreamableHTTP transport with event_store.
            The callback is only available when event_store is configured.
        """
        if self._request_context and self._request_context.close_sse_stream:  # pragma: no cover
            await self._request_context.close_sse_stream()

    async def close_standalone_sse_stream(self) -> None:
        """Close the standalone GET SSE stream to trigger client reconnection.

        This method closes the HTTP connection for the standalone GET stream used
        for unsolicited server-to-client notifications. The client SHOULD reconnect
        with Last-Event-ID to resume receiving notifications.

        Note:
            This is a no-op if not using StreamableHTTP transport with event_store.
            Currently, client reconnection for standalone GET streams is NOT
            implemented - this is a known gap.
        """
        if self._request_context and self._request_context.close_standalone_sse_stream:  # pragma: no cover
            await self._request_context.close_standalone_sse_stream()

    # Convenience methods for common log levels
    async def debug(self, data: Any, *, logger_name: str | None = None) -> None:
        """Send a debug log message."""
        await self.log("debug", data, logger_name=logger_name)

    async def info(self, data: Any, *, logger_name: str | None = None) -> None:
        """Send an info log message."""
        await self.log("info", data, logger_name=logger_name)

    async def warning(self, data: Any, *, logger_name: str | None = None) -> None:
        """Send a warning log message."""
        await self.log("warning", data, logger_name=logger_name)

    async def error(self, data: Any, *, logger_name: str | None = None) -> None:
        """Send an error log message."""
        await self.log("error", data, logger_name=logger_name)

mcp_server property 

mcp_server: MCPServer

Access to the MCPServer instance.

request_context property 

request_context: ServerRequestContext[
    LifespanContextT, RequestT
]

Access to the underlying request context.

report_progress async 

report_progress(
    progress: float,
    total: float | None = None,
    message: str | None = None,
) -> None

Report progress for the current operation.

Parameters:

Name Type Description Default
progress float

Current progress value (e.g., 24)

 required
total float | None

Optional total value (e.g., 100)

 None
message str | None

Optional message (e.g., "Starting render...")

 None
Source code in src/mcp/server/mcpserver/context.py 
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async def report_progress(self, progress: float, total: float | None = None, message: str | None = None) -> None:
    """Report progress for the current operation.

    Args:
        progress: Current progress value (e.g., 24)
        total: Optional total value (e.g., 100)
        message: Optional message (e.g., "Starting render...")
    """
    progress_token = self.request_context.meta.get("progress_token") if self.request_context.meta else None

    if progress_token is None:  # pragma: no cover
        return

    await self.request_context.session.send_progress_notification(
        progress_token=progress_token,
        progress=progress,
        total=total,
        message=message,
        related_request_id=self.request_id,
    )

read_resource async 

read_resource(
    uri: str | AnyUrl,
) -> Iterable[ReadResourceContents]

Read a resource by URI.

Parameters:

Name Type Description Default
uri str | AnyUrl

Resource URI to read

 required

Returns:

Type Description
Iterable[ReadResourceContents]

The resource content as either text or bytes
Source code in src/mcp/server/mcpserver/context.py 
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async def read_resource(self, uri: str | AnyUrl) -> Iterable[ReadResourceContents]:
    """Read a resource by URI.

    Args:
        uri: Resource URI to read

    Returns:
        The resource content as either text or bytes
    """
    assert self._mcp_server is not None, "Context is not available outside of a request"
    return await self._mcp_server.read_resource(uri, self)

elicit async 

elicit(
    message: str, schema: type[ElicitSchemaModelT]
) -> ElicitationResult[ElicitSchemaModelT]

Elicit information from the client/user.

This method can be used to interactively ask for additional information from the client within a tool's execution. The client might display the message to the user and collect a response according to the provided schema. If the client is an agent, it might decide how to handle the elicitation -- either by asking the user or automatically generating a response.

Parameters:

Name Type Description Default
message str

Message to present to the user

 required
schema type[ElicitSchemaModelT]

A Pydantic model class defining the expected response structure. According to the specification, only primitive types are allowed.

 required

Returns:

Type Description
ElicitationResult[ElicitSchemaModelT]

An ElicitationResult containing the action taken and the data if accepted
Note

Check the result.action to determine if the user accepted, declined, or cancelled. The result.data will only be populated if action is "accept" and validation succeeded.

Source code in src/mcp/server/mcpserver/context.py 
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async def elicit(
    self,
    message: str,
    schema: type[ElicitSchemaModelT],
) -> ElicitationResult[ElicitSchemaModelT]:
    """Elicit information from the client/user.

    This method can be used to interactively ask for additional information from the
    client within a tool's execution. The client might display the message to the
    user and collect a response according to the provided schema. If the client
    is an agent, it might decide how to handle the elicitation -- either by asking
    the user or automatically generating a response.

    Args:
        message: Message to present to the user
        schema: A Pydantic model class defining the expected response structure.
                According to the specification, only primitive types are allowed.

    Returns:
        An ElicitationResult containing the action taken and the data if accepted

    Note:
        Check the result.action to determine if the user accepted, declined, or cancelled.
        The result.data will only be populated if action is "accept" and validation succeeded.
    """

    return await elicit_with_validation(
        session=self.request_context.session,
        message=message,
        schema=schema,
        related_request_id=self.request_id,
    )

elicit_url async 

elicit_url(
    message: str, url: str, elicitation_id: str
) -> UrlElicitationResult

Request URL mode elicitation from the client.

This directs the user to an external URL for out-of-band interactions that must not pass through the MCP client. Use this for: - Collecting sensitive credentials (API keys, passwords) - OAuth authorization flows with third-party services - Payment and subscription flows - Any interaction where data should not pass through the LLM context

The response indicates whether the user consented to navigate to the URL. The actual interaction happens out-of-band. When the elicitation completes, call ctx.session.send_elicit_complete(elicitation_id) to notify the client.

Parameters:

Name Type Description Default
message str

Human-readable explanation of why the interaction is needed

 required
url str

The URL the user should navigate to

 required
elicitation_id str

Unique identifier for tracking this elicitation

 required

Returns:

Type Description
UrlElicitationResult

UrlElicitationResult indicating accept, decline, or cancel
Source code in src/mcp/server/mcpserver/context.py 
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async def elicit_url(
    self,
    message: str,
    url: str,
    elicitation_id: str,
) -> UrlElicitationResult:
    """Request URL mode elicitation from the client.

    This directs the user to an external URL for out-of-band interactions
    that must not pass through the MCP client. Use this for:
    - Collecting sensitive credentials (API keys, passwords)
    - OAuth authorization flows with third-party services
    - Payment and subscription flows
    - Any interaction where data should not pass through the LLM context

    The response indicates whether the user consented to navigate to the URL.
    The actual interaction happens out-of-band. When the elicitation completes,
    call `ctx.session.send_elicit_complete(elicitation_id)` to notify the client.

    Args:
        message: Human-readable explanation of why the interaction is needed
        url: The URL the user should navigate to
        elicitation_id: Unique identifier for tracking this elicitation

    Returns:
        UrlElicitationResult indicating accept, decline, or cancel
    """
    return await elicit_url(
        session=self.request_context.session,
        message=message,
        url=url,
        elicitation_id=elicitation_id,
        related_request_id=self.request_id,
    )

log async 

log(
    level: LoggingLevel,
    data: Any,
    *,
    logger_name: str | None = None
) -> None

Send a log message to the client.

Parameters:

Name Type Description Default
level LoggingLevel

Log level (debug, info, notice, warning, error, critical, alert, emergency)

 required
data Any

The data to be logged. Any JSON serializable type is allowed (string, dict, list, number, bool, etc.) per the MCP specification.

 required
logger_name str | None

Optional logger name

 None
Source code in src/mcp/server/mcpserver/context.py 
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async def log(
    self,
    level: LoggingLevel,
    data: Any,
    *,
    logger_name: str | None = None,
) -> None:
    """Send a log message to the client.

    Args:
        level: Log level (debug, info, notice, warning, error, critical,
            alert, emergency)
        data: The data to be logged. Any JSON serializable type is allowed
            (string, dict, list, number, bool, etc.) per the MCP specification.
        logger_name: Optional logger name
    """
    await self.request_context.session.send_log_message(
        level=level,
        data=data,
        logger=logger_name,
        related_request_id=self.request_id,
    )

client_id property 

client_id: str | None

Get the client ID if available.

Note: this reads from the MCP request's _meta params, not the OAuth bearer token. For that, use get_access_token().client_id.

request_id property 

request_id: str

Get the unique ID for this request.

session property 

session

Access to the underlying session for advanced usage.

close_sse_stream async 

close_sse_stream() -> None

Close the SSE stream to trigger client reconnection.

This method closes the HTTP connection for the current request, triggering client reconnection. Events continue to be stored in the event store and will be replayed when the client reconnects with Last-Event-ID.

Use this to implement polling behavior during long-running operations - the client will reconnect after the retry interval specified in the priming event.

Note

This is a no-op if not using StreamableHTTP transport with event_store. The callback is only available when event_store is configured.

Source code in src/mcp/server/mcpserver/context.py 
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async def close_sse_stream(self) -> None:
    """Close the SSE stream to trigger client reconnection.

    This method closes the HTTP connection for the current request, triggering
    client reconnection. Events continue to be stored in the event store and will
    be replayed when the client reconnects with Last-Event-ID.

    Use this to implement polling behavior during long-running operations -
    the client will reconnect after the retry interval specified in the priming event.

    Note:
        This is a no-op if not using StreamableHTTP transport with event_store.
        The callback is only available when event_store is configured.
    """
    if self._request_context and self._request_context.close_sse_stream:  # pragma: no cover
        await self._request_context.close_sse_stream()

close_standalone_sse_stream async 

close_standalone_sse_stream() -> None

Close the standalone GET SSE stream to trigger client reconnection.

This method closes the HTTP connection for the standalone GET stream used for unsolicited server-to-client notifications. The client SHOULD reconnect with Last-Event-ID to resume receiving notifications.

Note

This is a no-op if not using StreamableHTTP transport with event_store. Currently, client reconnection for standalone GET streams is NOT implemented - this is a known gap.

Source code in src/mcp/server/mcpserver/context.py 
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async def close_standalone_sse_stream(self) -> None:
    """Close the standalone GET SSE stream to trigger client reconnection.

    This method closes the HTTP connection for the standalone GET stream used
    for unsolicited server-to-client notifications. The client SHOULD reconnect
    with Last-Event-ID to resume receiving notifications.

    Note:
        This is a no-op if not using StreamableHTTP transport with event_store.
        Currently, client reconnection for standalone GET streams is NOT
        implemented - this is a known gap.
    """
    if self._request_context and self._request_context.close_standalone_sse_stream:  # pragma: no cover
        await self._request_context.close_standalone_sse_stream()

debug async 

debug(data: Any, *, logger_name: str | None = None) -> None

Send a debug log message.

Source code in src/mcp/server/mcpserver/context.py 
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async def debug(self, data: Any, *, logger_name: str | None = None) -> None:
    """Send a debug log message."""
    await self.log("debug", data, logger_name=logger_name)

info async 

info(data: Any, *, logger_name: str | None = None) -> None

Send an info log message.

Source code in src/mcp/server/mcpserver/context.py 
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async def info(self, data: Any, *, logger_name: str | None = None) -> None:
    """Send an info log message."""
    await self.log("info", data, logger_name=logger_name)

warning async 

warning(
    data: Any, *, logger_name: str | None = None
) -> None

Send a warning log message.

Source code in src/mcp/server/mcpserver/context.py 
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async def warning(self, data: Any, *, logger_name: str | None = None) -> None:
    """Send a warning log message."""
    await self.log("warning", data, logger_name=logger_name)

error async 

error(data: Any, *, logger_name: str | None = None) -> None

Send an error log message.

Source code in src/mcp/server/mcpserver/context.py 
276
277
278
async def error(self, data: Any, *, logger_name: str | None = None) -> None:
    """Send an error log message."""
    await self.log("error", data, logger_name=logger_name)

MCPServer

Bases: Generic[LifespanResultT]

Source code in src/mcp/server/mcpserver/server.py 
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class MCPServer(Generic[LifespanResultT]):
    def __init__(
        self,
        name: str | None = None,
        title: str | None = None,
        description: str | None = None,
        instructions: str | None = None,
        website_url: str | None = None,
        icons: list[Icon] | None = None,
        version: str | None = None,
        auth_server_provider: OAuthAuthorizationServerProvider[Any, Any, Any] | None = None,
        token_verifier: TokenVerifier | None = None,
        *,
        tools: list[Tool] | None = None,
        resources: list[Resource] | None = None,
        debug: bool = False,
        log_level: Literal["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"] = "INFO",
        warn_on_duplicate_resources: bool = True,
        warn_on_duplicate_tools: bool = True,
        warn_on_duplicate_prompts: bool = True,
        dependencies: list[str] | None = None,
        lifespan: Callable[[MCPServer[LifespanResultT]], AbstractAsyncContextManager[LifespanResultT]] | None = None,
        auth: AuthSettings | None = None,
    ):
        self.settings = Settings(
            debug=debug,
            log_level=log_level,
            warn_on_duplicate_resources=warn_on_duplicate_resources,
            warn_on_duplicate_tools=warn_on_duplicate_tools,
            warn_on_duplicate_prompts=warn_on_duplicate_prompts,
            dependencies=dependencies or [],
            lifespan=lifespan,
            auth=auth,
        )
        self.dependencies = self.settings.dependencies

        self._tool_manager = ToolManager(tools=tools, warn_on_duplicate_tools=self.settings.warn_on_duplicate_tools)
        self._resource_manager = ResourceManager(
            resources=resources, warn_on_duplicate_resources=self.settings.warn_on_duplicate_resources
        )
        self._prompt_manager = PromptManager(warn_on_duplicate_prompts=self.settings.warn_on_duplicate_prompts)
        self._lowlevel_server = Server(
            name=name or "mcp-server",
            title=title,
            description=description,
            instructions=instructions,
            website_url=website_url,
            icons=icons,
            version=version,
            on_list_tools=self._handle_list_tools,
            on_call_tool=self._handle_call_tool,
            on_list_resources=self._handle_list_resources,
            on_read_resource=self._handle_read_resource,
            on_list_resource_templates=self._handle_list_resource_templates,
            on_list_prompts=self._handle_list_prompts,
            on_get_prompt=self._handle_get_prompt,
            # TODO(Marcelo): It seems there's a type mismatch between the lifespan type from an MCPServer and Server.
            # We need to create a Lifespan type that is a generic on the server type, like Starlette does.
            lifespan=(lifespan_wrapper(self, self.settings.lifespan) if self.settings.lifespan else default_lifespan),  # type: ignore
        )
        # Validate auth configuration
        if self.settings.auth is not None:
            if auth_server_provider and token_verifier:  # pragma: no cover
                raise ValueError("Cannot specify both auth_server_provider and token_verifier")
            if not auth_server_provider and not token_verifier:  # pragma: no cover
                raise ValueError("Must specify either auth_server_provider or token_verifier when auth is enabled")
        elif auth_server_provider or token_verifier:  # pragma: no cover
            raise ValueError("Cannot specify auth_server_provider or token_verifier without auth settings")

        self._auth_server_provider = auth_server_provider
        self._token_verifier = token_verifier

        # Create token verifier from provider if needed (backwards compatibility)
        if auth_server_provider and not token_verifier:  # pragma: no cover
            self._token_verifier = ProviderTokenVerifier(auth_server_provider)
        self._custom_starlette_routes: list[Route] = []

        # Configure logging
        configure_logging(self.settings.log_level)

    @property
    def name(self) -> str:
        return self._lowlevel_server.name

    @property
    def title(self) -> str | None:
        return self._lowlevel_server.title

    @property
    def description(self) -> str | None:
        return self._lowlevel_server.description

    @property
    def instructions(self) -> str | None:
        return self._lowlevel_server.instructions

    @property
    def website_url(self) -> str | None:
        return self._lowlevel_server.website_url

    @property
    def icons(self) -> list[Icon] | None:
        return self._lowlevel_server.icons

    @property
    def version(self) -> str | None:
        return self._lowlevel_server.version

    @property
    def session_manager(self) -> StreamableHTTPSessionManager:
        """Get the StreamableHTTP session manager.

        This is exposed to enable advanced use cases like mounting multiple
        MCPServer instances in a single FastAPI application.

        Raises:
            RuntimeError: If called before streamable_http_app() has been called.
        """
        return self._lowlevel_server.session_manager  # pragma: no cover

    @overload
    def run(self, transport: Literal["stdio"] = ...) -> None: ...

    @overload
    def run(
        self,
        transport: Literal["sse"],
        *,
        host: str = ...,
        port: int = ...,
        sse_path: str = ...,
        message_path: str = ...,
        transport_security: TransportSecuritySettings | None = ...,
    ) -> None: ...

    @overload
    def run(
        self,
        transport: Literal["streamable-http"],
        *,
        host: str = ...,
        port: int = ...,
        streamable_http_path: str = ...,
        json_response: bool = ...,
        stateless_http: bool = ...,
        event_store: EventStore | None = ...,
        retry_interval: int | None = ...,
        transport_security: TransportSecuritySettings | None = ...,
    ) -> None: ...

    def run(
        self,
        transport: Literal["stdio", "sse", "streamable-http"] = "stdio",
        **kwargs: Any,
    ) -> None:
        """Run the MCP server. Note this is a synchronous function.

        Args:
            transport: Transport protocol to use ("stdio", "sse", or "streamable-http")
            **kwargs: Transport-specific options (see overloads for details)
        """
        TRANSPORTS = Literal["stdio", "sse", "streamable-http"]
        if transport not in TRANSPORTS.__args__:  # type: ignore  # pragma: no cover
            raise ValueError(f"Unknown transport: {transport}")

        match transport:
            case "stdio":
                anyio.run(self.run_stdio_async)
            case "sse":  # pragma: no cover
                anyio.run(lambda: self.run_sse_async(**kwargs))
            case "streamable-http":  # pragma: no cover
                anyio.run(lambda: self.run_streamable_http_async(**kwargs))

    async def _handle_list_tools(
        self, ctx: ServerRequestContext[LifespanResultT], params: PaginatedRequestParams | None
    ) -> ListToolsResult:
        return ListToolsResult(tools=await self.list_tools())

    async def _handle_call_tool(
        self, ctx: ServerRequestContext[LifespanResultT], params: CallToolRequestParams
    ) -> CallToolResult:
        context = Context(request_context=ctx, mcp_server=self)
        try:
            result = await self.call_tool(params.name, params.arguments or {}, context)
        except MCPError:
            raise
        except Exception as e:
            return CallToolResult(content=[TextContent(type="text", text=str(e))], is_error=True)
        if isinstance(result, CallToolResult):
            return result
        if isinstance(result, tuple) and len(result) == 2:
            unstructured_content, structured_content = result
            return CallToolResult(
                content=list(unstructured_content),  # type: ignore[arg-type]
                structured_content=structured_content,  # type: ignore[arg-type]
            )
        if isinstance(result, dict):  # pragma: no cover
            # TODO: this code path is unreachable — convert_result never returns a raw dict.
            # The call_tool return type (Sequence[ContentBlock] | dict[str, Any]) is wrong
            # and needs to be cleaned up.
            return CallToolResult(
                content=[TextContent(type="text", text=json.dumps(result, indent=2))],
                structured_content=result,
            )
        return CallToolResult(content=list(result))

    async def _handle_list_resources(
        self, ctx: ServerRequestContext[LifespanResultT], params: PaginatedRequestParams | None
    ) -> ListResourcesResult:
        return ListResourcesResult(resources=await self.list_resources())

    async def _handle_read_resource(
        self, ctx: ServerRequestContext[LifespanResultT], params: ReadResourceRequestParams
    ) -> ReadResourceResult:
        context = Context(request_context=ctx, mcp_server=self)
        results = await self.read_resource(params.uri, context)
        contents: list[TextResourceContents | BlobResourceContents] = []
        for item in results:
            if isinstance(item.content, bytes):
                contents.append(
                    BlobResourceContents(
                        uri=params.uri,
                        blob=base64.b64encode(item.content).decode(),
                        mime_type=item.mime_type or "application/octet-stream",
                        _meta=item.meta,
                    )
                )
            else:
                contents.append(
                    TextResourceContents(
                        uri=params.uri,
                        text=item.content,
                        mime_type=item.mime_type or "text/plain",
                        _meta=item.meta,
                    )
                )
        return ReadResourceResult(contents=contents)

    async def _handle_list_resource_templates(
        self, ctx: ServerRequestContext[LifespanResultT], params: PaginatedRequestParams | None
    ) -> ListResourceTemplatesResult:
        return ListResourceTemplatesResult(resource_templates=await self.list_resource_templates())

    async def _handle_list_prompts(
        self, ctx: ServerRequestContext[LifespanResultT], params: PaginatedRequestParams | None
    ) -> ListPromptsResult:
        return ListPromptsResult(prompts=await self.list_prompts())

    async def _handle_get_prompt(
        self, ctx: ServerRequestContext[LifespanResultT], params: GetPromptRequestParams
    ) -> GetPromptResult:
        context = Context(request_context=ctx, mcp_server=self)
        return await self.get_prompt(params.name, params.arguments, context)

    async def list_tools(self) -> list[MCPTool]:
        """List all available tools."""
        tools = self._tool_manager.list_tools()
        return [
            MCPTool(
                name=info.name,
                title=info.title,
                description=info.description,
                input_schema=info.parameters,
                output_schema=info.output_schema,
                annotations=info.annotations,
                icons=info.icons,
                _meta=info.meta,
            )
            for info in tools
        ]

    async def call_tool(
        self, name: str, arguments: dict[str, Any], context: Context[LifespanResultT, Any] | None = None
    ) -> Sequence[ContentBlock] | dict[str, Any]:
        """Call a tool by name with arguments."""
        if context is None:
            context = Context(mcp_server=self)
        return await self._tool_manager.call_tool(name, arguments, context, convert_result=True)

    async def list_resources(self) -> list[MCPResource]:
        """List all available resources."""

        resources = self._resource_manager.list_resources()
        return [
            MCPResource(
                uri=resource.uri,
                name=resource.name or "",
                title=resource.title,
                description=resource.description,
                mime_type=resource.mime_type,
                icons=resource.icons,
                annotations=resource.annotations,
                _meta=resource.meta,
            )
            for resource in resources
        ]

    async def list_resource_templates(self) -> list[MCPResourceTemplate]:
        templates = self._resource_manager.list_templates()
        return [
            MCPResourceTemplate(
                uri_template=template.uri_template,
                name=template.name,
                title=template.title,
                description=template.description,
                mime_type=template.mime_type,
                icons=template.icons,
                annotations=template.annotations,
                _meta=template.meta,
            )
            for template in templates
        ]

    async def read_resource(
        self, uri: AnyUrl | str, context: Context[LifespanResultT, Any] | None = None
    ) -> Iterable[ReadResourceContents]:
        """Read a resource by URI."""
        if context is None:
            context = Context(mcp_server=self)
        try:
            resource = await self._resource_manager.get_resource(uri, context)
        except ValueError as exc:
            raise ResourceError(f"Unknown resource: {uri}") from exc

        try:
            content = await resource.read()
            return [ReadResourceContents(content=content, mime_type=resource.mime_type, meta=resource.meta)]
        except Exception as exc:
            logger.exception(f"Error getting resource {uri}")
            # If an exception happens when reading the resource, we should not leak the exception to the client.
            raise ResourceError(f"Error reading resource {uri}") from exc

    def add_tool(
        self,
        fn: Callable[..., Any],
        name: str | None = None,
        title: str | None = None,
        description: str | None = None,
        annotations: ToolAnnotations | None = None,
        icons: list[Icon] | None = None,
        meta: dict[str, Any] | None = None,
        structured_output: bool | None = None,
    ) -> None:
        """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:
            fn: The function to register as a tool
            name: Optional name for the tool (defaults to function name)
            title: Optional human-readable title for the tool
            description: Optional description of what the tool does
            annotations: Optional ToolAnnotations providing additional tool information
            icons: Optional list of icons for the tool
            meta: Optional metadata dictionary for the tool
            structured_output: Controls whether the tool's output is structured or unstructured
                - If None, auto-detects based on the function's return type annotation
                - If True, creates a structured tool (return type annotation permitting)
                - If False, unconditionally creates an unstructured tool
        """
        self._tool_manager.add_tool(
            fn,
            name=name,
            title=title,
            description=description,
            annotations=annotations,
            icons=icons,
            meta=meta,
            structured_output=structured_output,
        )

    def remove_tool(self, name: str) -> None:
        """Remove a tool from the server by name.

        Args:
            name: The name of the tool to remove

        Raises:
            ToolError: If the tool does not exist
        """
        self._tool_manager.remove_tool(name)

    def tool(
        self,
        name: str | None = None,
        title: str | None = None,
        description: str | None = None,
        annotations: ToolAnnotations | None = None,
        icons: list[Icon] | None = None,
        meta: dict[str, Any] | None = None,
        structured_output: bool | None = None,
    ) -> Callable[[_CallableT], _CallableT]:
        """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.

        Args:
            name: Optional name for the tool (defaults to function name)
            title: Optional human-readable title for the tool
            description: Optional description of what the tool does
            annotations: Optional ToolAnnotations providing additional tool information
            icons: Optional list of icons for the tool
            meta: Optional metadata dictionary for the tool
            structured_output: Controls whether the tool's output is structured or unstructured
                - If None, auto-detects based on the function's return type annotation
                - If True, creates a structured tool (return type annotation permitting)
                - If False, unconditionally creates an unstructured tool

        Example:
            ```python
            @server.tool()
            def my_tool(x: int) -> str:
                return str(x)
            ```

            ```python
            @server.tool()
            async def tool_with_context(x: int, ctx: Context) -> str:
                await ctx.info(f"Processing {x}")
                return str(x)
            ```

            ```python
            @server.tool()
            async def async_tool(x: int, context: Context) -> str:
                await context.report_progress(50, 100)
                return str(x)
            ```
        """
        # Check if user passed function directly instead of calling decorator
        if callable(name):
            raise TypeError(
                "The @tool decorator was used incorrectly. Did you forget to call it? Use @tool() instead of @tool"
            )

        def decorator(fn: _CallableT) -> _CallableT:
            self.add_tool(
                fn,
                name=name,
                title=title,
                description=description,
                annotations=annotations,
                icons=icons,
                meta=meta,
                structured_output=structured_output,
            )
            return fn

        return decorator

    def completion(self):
        """Decorator to register a completion handler.

        The completion handler receives:
        - ref: PromptReference or ResourceTemplateReference
        - argument: CompletionArgument with name and partial value
        - context: Optional CompletionContext with previously resolved arguments

        Example:
            ```python
            @mcp.completion()
            async def handle_completion(ref, argument, context):
                if isinstance(ref, ResourceTemplateReference):
                    # Return completions based on ref, argument, and context
                    return Completion(values=["option1", "option2"])
                return None
            ```
        """

        def decorator(func: _CallableT) -> _CallableT:
            async def handler(
                ctx: ServerRequestContext[LifespanResultT], params: CompleteRequestParams
            ) -> CompleteResult:
                result = await func(params.ref, params.argument, params.context)
                return CompleteResult(
                    completion=result if result is not None else Completion(values=[], total=None, has_more=None),
                )

            # TODO(maxisbey): remove private access — completion needs post-construction
            #   handler registration, find a better pattern for this
            self._lowlevel_server._add_request_handler(  # pyright: ignore[reportPrivateUsage]
                "completion/complete", handler
            )
            return func

        return decorator

    def add_resource(self, resource: Resource) -> None:
        """Add a resource to the server.

        Args:
            resource: A Resource instance to add
        """
        self._resource_manager.add_resource(resource)

    def resource(
        self,
        uri: str,
        *,
        name: str | None = None,
        title: str | None = None,
        description: str | None = None,
        mime_type: str | None = None,
        icons: list[Icon] | None = None,
        annotations: Annotations | None = None,
        meta: dict[str, Any] | None = None,
    ) -> Callable[[_CallableT], _CallableT]:
        """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

        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
            title: Optional human-readable title for the resource
            description: Optional description of the resource
            mime_type: Optional MIME type for the resource
            icons: Optional list of icons for the resource
            annotations: Optional annotations for the resource
            meta: Optional metadata dictionary for the resource

        Example:
            ```python
            @server.resource("resource://my-resource")
            def get_data() -> str:
                return "Hello, world!"

            @server.resource("resource://my-resource")
            async def 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(city: str) -> str:
                data = await fetch_weather(city)
                return f"Weather for {city}: {data}"
            ```
        """
        # Check if user passed function directly instead of calling decorator
        if callable(uri):
            raise TypeError(
                "The @resource decorator was used incorrectly. "
                "Did you forget to call it? Use @resource('uri') instead of @resource"
            )

        def decorator(fn: _CallableT) -> _CallableT:
            # Check if this should be a template
            sig = inspect.signature(fn)
            has_uri_params = "{" in uri and "}" in uri
            has_func_params = bool(sig.parameters)

            if has_uri_params or has_func_params:
                # Check for Context parameter to exclude from validation
                context_param = find_context_parameter(fn)

                # Validate that URI params match function params (excluding context)
                uri_params = set(re.findall(r"{(\w+)}", uri))
                # We need to remove the context_param from the resource function if
                # there is any.
                func_params = {p for p in sig.parameters.keys() if p != context_param}

                if uri_params != func_params:
                    raise ValueError(
                        f"Mismatch between URI parameters {uri_params} and function parameters {func_params}"
                    )

                # Register as template
                self._resource_manager.add_template(
                    fn=fn,
                    uri_template=uri,
                    name=name,
                    title=title,
                    description=description,
                    mime_type=mime_type,
                    icons=icons,
                    annotations=annotations,
                    meta=meta,
                )
            else:
                # Register as regular resource
                resource = FunctionResource.from_function(
                    fn=fn,
                    uri=uri,
                    name=name,
                    title=title,
                    description=description,
                    mime_type=mime_type,
                    icons=icons,
                    annotations=annotations,
                    meta=meta,
                )
                self.add_resource(resource)
            return fn

        return decorator

    def add_prompt(self, prompt: Prompt) -> None:
        """Add a prompt to the server.

        Args:
            prompt: A Prompt instance to add
        """
        self._prompt_manager.add_prompt(prompt)

    def prompt(
        self,
        name: str | None = None,
        title: str | None = None,
        description: str | None = None,
        icons: list[Icon] | None = None,
    ) -> Callable[[_CallableT], _CallableT]:
        """Decorator to register a prompt.

        Args:
            name: Optional name for the prompt (defaults to function name)
            title: Optional human-readable title for the prompt
            description: Optional description of what the prompt does
            icons: Optional list of icons for the prompt

        Example:
            ```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:\n{schema}"
                    }
                ]

            @server.prompt()
            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
                            }
                        }
                    }
                ]
            ```
        """
        # Check if user passed function directly instead of calling decorator
        if callable(name):
            raise TypeError(
                "The @prompt decorator was used incorrectly. "
                "Did you forget to call it? Use @prompt() instead of @prompt"
            )

        def decorator(func: _CallableT) -> _CallableT:
            prompt = Prompt.from_function(func, name=name, title=title, description=description, icons=icons)
            self.add_prompt(prompt)
            return func

        return decorator

    def custom_route(
        self,
        path: str,
        methods: list[str],
        name: str | None = None,
        include_in_schema: bool = True,
    ):
        """Decorator to register a custom HTTP route on the MCP 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.

        Routes using this decorator will not require authorization. It is intended
        for uses that are either a part of authorization flows or intended to be
        public such as health check endpoints.

        Args:
            path: URL path for the route (e.g., "/oauth/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

        Example:
            ```python
            @server.custom_route("/health", methods=["GET"])
            async def health_check(request: Request) -> Response:
                return JSONResponse({"status": "ok"})
            ```
        """

        def decorator(  # pragma: no cover
            func: Callable[[Request], Awaitable[Response]],
        ) -> Callable[[Request], Awaitable[Response]]:
            self._custom_starlette_routes.append(
                Route(path, endpoint=func, methods=methods, name=name, include_in_schema=include_in_schema)
            )
            return func

        return decorator  # pragma: no cover

    async def run_stdio_async(self) -> None:
        """Run the server using stdio transport."""
        async with stdio_server() as (read_stream, write_stream):
            await self._lowlevel_server.run(
                read_stream,
                write_stream,
                self._lowlevel_server.create_initialization_options(),
            )

    async def run_sse_async(  # pragma: no cover
        self,
        *,
        host: str = "127.0.0.1",
        port: int = 8000,
        sse_path: str = "/sse",
        message_path: str = "/messages/",
        transport_security: TransportSecuritySettings | None = None,
    ) -> None:
        """Run the server using SSE transport."""
        import uvicorn

        starlette_app = self.sse_app(
            sse_path=sse_path,
            message_path=message_path,
            transport_security=transport_security,
            host=host,
        )

        config = uvicorn.Config(
            starlette_app,
            host=host,
            port=port,
            log_level=self.settings.log_level.lower(),
        )
        server = uvicorn.Server(config)
        await server.serve()

    async def run_streamable_http_async(  # pragma: no cover
        self,
        *,
        host: str = "127.0.0.1",
        port: int = 8000,
        streamable_http_path: str = "/mcp",
        json_response: bool = False,
        stateless_http: bool = False,
        event_store: EventStore | None = None,
        retry_interval: int | None = None,
        transport_security: TransportSecuritySettings | None = None,
    ) -> None:
        """Run the server using StreamableHTTP transport."""
        import uvicorn

        starlette_app = self.streamable_http_app(
            streamable_http_path=streamable_http_path,
            json_response=json_response,
            stateless_http=stateless_http,
            event_store=event_store,
            retry_interval=retry_interval,
            transport_security=transport_security,
            host=host,
        )

        config = uvicorn.Config(
            starlette_app,
            host=host,
            port=port,
            log_level=self.settings.log_level.lower(),
        )
        server = uvicorn.Server(config)
        await server.serve()

    def sse_app(
        self,
        *,
        sse_path: str = "/sse",
        message_path: str = "/messages/",
        transport_security: TransportSecuritySettings | None = None,
        host: str = "127.0.0.1",
    ) -> Starlette:
        """Return an instance of the SSE server app."""
        # Auto-enable DNS rebinding protection for localhost (IPv4 and IPv6)
        if transport_security is None and host in ("127.0.0.1", "localhost", "::1"):
            transport_security = TransportSecuritySettings(
                enable_dns_rebinding_protection=True,
                allowed_hosts=["127.0.0.1:*", "localhost:*", "[::1]:*"],
                allowed_origins=["http://127.0.0.1:*", "http://localhost:*", "http://[::1]:*"],
            )

        sse = SseServerTransport(message_path, security_settings=transport_security)

        async def handle_sse(scope: Scope, receive: Receive, send: Send):  # pragma: no cover
            # Add client ID from auth context into request context if available

            async with sse.connect_sse(scope, receive, send) as streams:
                await self._lowlevel_server.run(
                    streams[0], streams[1], self._lowlevel_server.create_initialization_options()
                )
            return Response()

        # Create routes
        routes: list[Route | Mount] = []
        middleware: list[Middleware] = []
        required_scopes: list[str] = []

        # Set up auth if configured
        if self.settings.auth:  # pragma: no cover
            required_scopes = self.settings.auth.required_scopes or []

            # Add auth middleware if token verifier is available
            if self._token_verifier:
                middleware = [
                    # extract auth info from request (but do not require it)
                    Middleware(
                        AuthenticationMiddleware,
                        backend=BearerAuthBackend(self._token_verifier),
                    ),
                    # Add the auth context middleware to store
                    # authenticated user in a contextvar
                    Middleware(AuthContextMiddleware),
                ]

            # Add auth endpoints if auth server provider is configured
            if self._auth_server_provider:
                from mcp.server.auth.routes import create_auth_routes

                routes.extend(
                    create_auth_routes(
                        provider=self._auth_server_provider,
                        issuer_url=self.settings.auth.issuer_url,
                        service_documentation_url=self.settings.auth.service_documentation_url,
                        client_registration_options=self.settings.auth.client_registration_options,
                        revocation_options=self.settings.auth.revocation_options,
                    )
                )

        # When auth is configured, require authentication
        if self._token_verifier:  # pragma: no cover
            # Determine resource metadata URL
            resource_metadata_url = None
            if self.settings.auth and self.settings.auth.resource_server_url:
                from mcp.server.auth.routes import build_resource_metadata_url

                # Build compliant metadata URL for WWW-Authenticate header
                resource_metadata_url = build_resource_metadata_url(self.settings.auth.resource_server_url)

            # Auth is enabled, wrap the endpoints with RequireAuthMiddleware
            routes.append(
                Route(
                    sse_path,
                    endpoint=RequireAuthMiddleware(handle_sse, required_scopes, resource_metadata_url),
                    methods=["GET"],
                )
            )
            routes.append(
                Mount(
                    message_path,
                    app=RequireAuthMiddleware(sse.handle_post_message, required_scopes, resource_metadata_url),
                )
            )
        else:
            # Auth is disabled, no need for RequireAuthMiddleware
            # Since handle_sse is an ASGI app, we need to create a compatible endpoint
            async def sse_endpoint(request: Request) -> Response:  # pragma: no cover
                # Convert the Starlette request to ASGI parameters
                return await handle_sse(request.scope, request.receive, request._send)  # type: ignore[reportPrivateUsage]

            routes.append(
                Route(
                    sse_path,
                    endpoint=sse_endpoint,
                    methods=["GET"],
                )
            )
            routes.append(
                Mount(
                    message_path,
                    app=sse.handle_post_message,
                )
            )
        # Add protected resource metadata endpoint if configured as RS
        if self.settings.auth and self.settings.auth.resource_server_url:  # pragma: no cover
            from mcp.server.auth.routes import create_protected_resource_routes

            routes.extend(
                create_protected_resource_routes(
                    resource_url=self.settings.auth.resource_server_url,
                    authorization_servers=[self.settings.auth.issuer_url],
                    scopes_supported=self.settings.auth.required_scopes,
                )
            )

        # mount these routes last, so they have the lowest route matching precedence
        routes.extend(self._custom_starlette_routes)

        # Create Starlette app with routes and middleware
        return Starlette(debug=self.settings.debug, routes=routes, middleware=middleware)

    def streamable_http_app(
        self,
        *,
        streamable_http_path: str = "/mcp",
        json_response: bool = False,
        stateless_http: bool = False,
        event_store: EventStore | None = None,
        retry_interval: int | None = None,
        transport_security: TransportSecuritySettings | None = None,
        host: str = "127.0.0.1",
    ) -> Starlette:
        """Return an instance of the StreamableHTTP server app."""
        return self._lowlevel_server.streamable_http_app(
            streamable_http_path=streamable_http_path,
            json_response=json_response,
            stateless_http=stateless_http,
            event_store=event_store,
            retry_interval=retry_interval,
            transport_security=transport_security,
            host=host,
            auth=self.settings.auth,
            token_verifier=self._token_verifier,
            auth_server_provider=self._auth_server_provider,
            custom_starlette_routes=self._custom_starlette_routes,
            debug=self.settings.debug,
        )

    async def list_prompts(self) -> list[MCPPrompt]:
        """List all available prompts."""
        prompts = self._prompt_manager.list_prompts()
        return [
            MCPPrompt(
                name=prompt.name,
                title=prompt.title,
                description=prompt.description,
                arguments=[
                    MCPPromptArgument(
                        name=arg.name,
                        description=arg.description,
                        required=arg.required,
                    )
                    for arg in (prompt.arguments or [])
                ],
                icons=prompt.icons,
            )
            for prompt in prompts
        ]

    async def get_prompt(
        self, name: str, arguments: dict[str, Any] | None = None, context: Context[LifespanResultT, Any] | None = None
    ) -> GetPromptResult:
        """Get a prompt by name with arguments."""
        if context is None:
            context = Context(mcp_server=self)
        try:
            prompt = self._prompt_manager.get_prompt(name)
            if not prompt:
                raise ValueError(f"Unknown prompt: {name}")

            messages = await prompt.render(arguments, context)

            return GetPromptResult(
                description=prompt.description,
                messages=pydantic_core.to_jsonable_python(messages),
            )
        except Exception as e:
            logger.exception(f"Error getting prompt {name}")
            raise ValueError(str(e)) from e

session_manager property 

session_manager: StreamableHTTPSessionManager

Get the StreamableHTTP session manager.

This is exposed to enable advanced use cases like mounting multiple MCPServer instances in a single FastAPI application.

Raises:

Type Description
RuntimeError

If called before streamable_http_app() has been called.

run 

run(transport: Literal['stdio'] = ...) -> None

run(
    transport: Literal["sse"],
    *,
    host: str = ...,
    port: int = ...,
    sse_path: str = ...,
    message_path: str = ...,
    transport_security: (
        TransportSecuritySettings | None
    ) = ...
) -> None

run(
    transport: Literal["streamable-http"],
    *,
    host: str = ...,
    port: int = ...,
    streamable_http_path: str = ...,
    json_response: bool = ...,
    stateless_http: bool = ...,
    event_store: EventStore | None = ...,
    retry_interval: int | None = ...,
    transport_security: (
        TransportSecuritySettings | None
    ) = ...
) -> None

run(
    transport: Literal[
        "stdio", "sse", "streamable-http"
    ] = "stdio",
    **kwargs: Any
) -> None

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

Parameters:

Name Type Description Default
transport Literal['stdio', 'sse', 'streamable-http']

Transport protocol to use ("stdio", "sse", or "streamable-http")

 'stdio'
**kwargs Any

Transport-specific options (see overloads for details)

 {}
Source code in src/mcp/server/mcpserver/server.py 
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def run(
    self,
    transport: Literal["stdio", "sse", "streamable-http"] = "stdio",
    **kwargs: Any,
) -> None:
    """Run the MCP server. Note this is a synchronous function.

    Args:
        transport: Transport protocol to use ("stdio", "sse", or "streamable-http")
        **kwargs: Transport-specific options (see overloads for details)
    """
    TRANSPORTS = Literal["stdio", "sse", "streamable-http"]
    if transport not in TRANSPORTS.__args__:  # type: ignore  # pragma: no cover
        raise ValueError(f"Unknown transport: {transport}")

    match transport:
        case "stdio":
            anyio.run(self.run_stdio_async)
        case "sse":  # pragma: no cover
            anyio.run(lambda: self.run_sse_async(**kwargs))
        case "streamable-http":  # pragma: no cover
            anyio.run(lambda: self.run_streamable_http_async(**kwargs))

list_tools async 

list_tools() -> list[Tool]

List all available tools.

Source code in src/mcp/server/mcpserver/server.py 
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async def list_tools(self) -> list[MCPTool]:
    """List all available tools."""
    tools = self._tool_manager.list_tools()
    return [
        MCPTool(
            name=info.name,
            title=info.title,
            description=info.description,
            input_schema=info.parameters,
            output_schema=info.output_schema,
            annotations=info.annotations,
            icons=info.icons,
            _meta=info.meta,
        )
        for info in tools
    ]

call_tool async 

call_tool(
    name: str,
    arguments: dict[str, Any],
    context: Context[LifespanResultT, Any] | None = None,
) -> Sequence[ContentBlock] | dict[str, Any]

Call a tool by name with arguments.

Source code in src/mcp/server/mcpserver/server.py 
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async def call_tool(
    self, name: str, arguments: dict[str, Any], context: Context[LifespanResultT, Any] | None = None
) -> Sequence[ContentBlock] | dict[str, Any]:
    """Call a tool by name with arguments."""
    if context is None:
        context = Context(mcp_server=self)
    return await self._tool_manager.call_tool(name, arguments, context, convert_result=True)

list_resources async 

list_resources() -> list[Resource]

List all available resources.

Source code in src/mcp/server/mcpserver/server.py 
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async def list_resources(self) -> list[MCPResource]:
    """List all available resources."""

    resources = self._resource_manager.list_resources()
    return [
        MCPResource(
            uri=resource.uri,
            name=resource.name or "",
            title=resource.title,
            description=resource.description,
            mime_type=resource.mime_type,
            icons=resource.icons,
            annotations=resource.annotations,
            _meta=resource.meta,
        )
        for resource in resources
    ]

read_resource async 

read_resource(
    uri: AnyUrl | str,
    context: Context[LifespanResultT, Any] | None = None,
) -> Iterable[ReadResourceContents]

Read a resource by URI.

Source code in src/mcp/server/mcpserver/server.py 
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async def read_resource(
    self, uri: AnyUrl | str, context: Context[LifespanResultT, Any] | None = None
) -> Iterable[ReadResourceContents]:
    """Read a resource by URI."""
    if context is None:
        context = Context(mcp_server=self)
    try:
        resource = await self._resource_manager.get_resource(uri, context)
    except ValueError as exc:
        raise ResourceError(f"Unknown resource: {uri}") from exc

    try:
        content = await resource.read()
        return [ReadResourceContents(content=content, mime_type=resource.mime_type, meta=resource.meta)]
    except Exception as exc:
        logger.exception(f"Error getting resource {uri}")
        # If an exception happens when reading the resource, we should not leak the exception to the client.
        raise ResourceError(f"Error reading resource {uri}") from exc

add_tool 

add_tool(
    fn: Callable[..., Any],
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    annotations: ToolAnnotations | None = None,
    icons: list[Icon] | None = None,
    meta: dict[str, Any] | None = None,
    structured_output: bool | None = None,
) -> None

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.

Parameters:

Name Type Description Default
fn Callable[..., Any]

The function to register as a tool

 required
name str | None

Optional name for the tool (defaults to function name)

 None
title str | None

Optional human-readable title for the tool

 None
description str | None

Optional description of what the tool does

 None
annotations ToolAnnotations | None

Optional ToolAnnotations providing additional tool information

 None
icons list[Icon] | None

Optional list of icons for the tool

 None
meta dict[str, Any] | None

Optional metadata dictionary for the tool

 None
structured_output bool | None

Controls whether the tool's output is structured or unstructured - If None, auto-detects based on the function's return type annotation - If True, creates a structured tool (return type annotation permitting) - If False, unconditionally creates an unstructured tool

 None
Source code in src/mcp/server/mcpserver/server.py 
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def add_tool(
    self,
    fn: Callable[..., Any],
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    annotations: ToolAnnotations | None = None,
    icons: list[Icon] | None = None,
    meta: dict[str, Any] | None = None,
    structured_output: bool | None = None,
) -> None:
    """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:
        fn: The function to register as a tool
        name: Optional name for the tool (defaults to function name)
        title: Optional human-readable title for the tool
        description: Optional description of what the tool does
        annotations: Optional ToolAnnotations providing additional tool information
        icons: Optional list of icons for the tool
        meta: Optional metadata dictionary for the tool
        structured_output: Controls whether the tool's output is structured or unstructured
            - If None, auto-detects based on the function's return type annotation
            - If True, creates a structured tool (return type annotation permitting)
            - If False, unconditionally creates an unstructured tool
    """
    self._tool_manager.add_tool(
        fn,
        name=name,
        title=title,
        description=description,
        annotations=annotations,
        icons=icons,
        meta=meta,
        structured_output=structured_output,
    )

remove_tool 

remove_tool(name: str) -> None

Remove a tool from the server by name.

Parameters:

Name Type Description Default
name str

The name of the tool to remove

 required

Raises:

Type Description
ToolError

If the tool does not exist
Source code in src/mcp/server/mcpserver/server.py 
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def remove_tool(self, name: str) -> None:
    """Remove a tool from the server by name.

    Args:
        name: The name of the tool to remove

    Raises:
        ToolError: If the tool does not exist
    """
    self._tool_manager.remove_tool(name)

tool 

tool(
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    annotations: ToolAnnotations | None = None,
    icons: list[Icon] | None = None,
    meta: dict[str, Any] | None = None,
    structured_output: bool | None = None,
) -> Callable[[_CallableT], _CallableT]

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.

Parameters:

Name Type Description Default
name str | None

Optional name for the tool (defaults to function name)

 None
title str | None

Optional human-readable title for the tool

 None
description str | None

Optional description of what the tool does

 None
annotations ToolAnnotations | None

Optional ToolAnnotations providing additional tool information

 None
icons list[Icon] | None

Optional list of icons for the tool

 None
meta dict[str, Any] | None

Optional metadata dictionary for the tool

 None
structured_output bool | None

Controls whether the tool's output is structured or unstructured - If None, auto-detects based on the function's return type annotation - If True, creates a structured tool (return type annotation permitting) - If False, unconditionally creates an unstructured tool

 None
Example 
@server.tool()
def my_tool(x: int) -> str:
    return str(x)

@server.tool()
async def tool_with_context(x: int, ctx: Context) -> str:
    await ctx.info(f"Processing {x}")
    return str(x)

@server.tool()
async def async_tool(x: int, context: Context) -> str:
    await context.report_progress(50, 100)
    return str(x)
Source code in src/mcp/server/mcpserver/server.py 
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def tool(
    self,
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    annotations: ToolAnnotations | None = None,
    icons: list[Icon] | None = None,
    meta: dict[str, Any] | None = None,
    structured_output: bool | None = None,
) -> Callable[[_CallableT], _CallableT]:
    """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.

    Args:
        name: Optional name for the tool (defaults to function name)
        title: Optional human-readable title for the tool
        description: Optional description of what the tool does
        annotations: Optional ToolAnnotations providing additional tool information
        icons: Optional list of icons for the tool
        meta: Optional metadata dictionary for the tool
        structured_output: Controls whether the tool's output is structured or unstructured
            - If None, auto-detects based on the function's return type annotation
            - If True, creates a structured tool (return type annotation permitting)
            - If False, unconditionally creates an unstructured tool

    Example:
        ```python
        @server.tool()
        def my_tool(x: int) -> str:
            return str(x)
        ```

        ```python
        @server.tool()
        async def tool_with_context(x: int, ctx: Context) -> str:
            await ctx.info(f"Processing {x}")
            return str(x)
        ```

        ```python
        @server.tool()
        async def async_tool(x: int, context: Context) -> str:
            await context.report_progress(50, 100)
            return str(x)
        ```
    """
    # Check if user passed function directly instead of calling decorator
    if callable(name):
        raise TypeError(
            "The @tool decorator was used incorrectly. Did you forget to call it? Use @tool() instead of @tool"
        )

    def decorator(fn: _CallableT) -> _CallableT:
        self.add_tool(
            fn,
            name=name,
            title=title,
            description=description,
            annotations=annotations,
            icons=icons,
            meta=meta,
            structured_output=structured_output,
        )
        return fn

    return decorator

completion 

completion()

Decorator to register a completion handler.

The completion handler receives: - ref: PromptReference or ResourceTemplateReference - argument: CompletionArgument with name and partial value - context: Optional CompletionContext with previously resolved arguments

Example 
@mcp.completion()
async def handle_completion(ref, argument, context):
    if isinstance(ref, ResourceTemplateReference):
        # Return completions based on ref, argument, and context
        return Completion(values=["option1", "option2"])
    return None
Source code in src/mcp/server/mcpserver/server.py 
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def completion(self):
    """Decorator to register a completion handler.

    The completion handler receives:
    - ref: PromptReference or ResourceTemplateReference
    - argument: CompletionArgument with name and partial value
    - context: Optional CompletionContext with previously resolved arguments

    Example:
        ```python
        @mcp.completion()
        async def handle_completion(ref, argument, context):
            if isinstance(ref, ResourceTemplateReference):
                # Return completions based on ref, argument, and context
                return Completion(values=["option1", "option2"])
            return None
        ```
    """

    def decorator(func: _CallableT) -> _CallableT:
        async def handler(
            ctx: ServerRequestContext[LifespanResultT], params: CompleteRequestParams
        ) -> CompleteResult:
            result = await func(params.ref, params.argument, params.context)
            return CompleteResult(
                completion=result if result is not None else Completion(values=[], total=None, has_more=None),
            )

        # TODO(maxisbey): remove private access — completion needs post-construction
        #   handler registration, find a better pattern for this
        self._lowlevel_server._add_request_handler(  # pyright: ignore[reportPrivateUsage]
            "completion/complete", handler
        )
        return func

    return decorator

add_resource 

add_resource(resource: Resource) -> None

Add a resource to the server.

Parameters:

Name Type Description Default
resource Resource

A Resource instance to add

 required
Source code in src/mcp/server/mcpserver/server.py 
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def add_resource(self, resource: Resource) -> None:
    """Add a resource to the server.

    Args:
        resource: A Resource instance to add
    """
    self._resource_manager.add_resource(resource)

resource 

resource(
    uri: str,
    *,
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    mime_type: str | None = None,
    icons: list[Icon] | None = None,
    annotations: Annotations | None = None,
    meta: dict[str, Any] | None = None
) -> Callable[[_CallableT], _CallableT]

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

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

Parameters:

Name Type Description Default
uri str

URI for the resource (e.g. "resource://my-resource" or "resource://{param}")

 required
name str | None

Optional name for the resource

 None
title str | None

Optional human-readable title for the resource

 None
description str | None

Optional description of the resource

 None
mime_type str | None

Optional MIME type for the resource

 None
icons list[Icon] | None

Optional list of icons for the resource

 None
annotations Annotations | None

Optional annotations for the resource

 None
meta dict[str, Any] | None

Optional metadata dictionary for the resource

 None
Example 
@server.resource("resource://my-resource")
def get_data() -> str:
    return "Hello, world!"

@server.resource("resource://my-resource")
async def 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(city: str) -> str:
    data = await fetch_weather(city)
    return f"Weather for {city}: {data}"
Source code in src/mcp/server/mcpserver/server.py 
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def resource(
    self,
    uri: str,
    *,
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    mime_type: str | None = None,
    icons: list[Icon] | None = None,
    annotations: Annotations | None = None,
    meta: dict[str, Any] | None = None,
) -> Callable[[_CallableT], _CallableT]:
    """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

    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
        title: Optional human-readable title for the resource
        description: Optional description of the resource
        mime_type: Optional MIME type for the resource
        icons: Optional list of icons for the resource
        annotations: Optional annotations for the resource
        meta: Optional metadata dictionary for the resource

    Example:
        ```python
        @server.resource("resource://my-resource")
        def get_data() -> str:
            return "Hello, world!"

        @server.resource("resource://my-resource")
        async def 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(city: str) -> str:
            data = await fetch_weather(city)
            return f"Weather for {city}: {data}"
        ```
    """
    # Check if user passed function directly instead of calling decorator
    if callable(uri):
        raise TypeError(
            "The @resource decorator was used incorrectly. "
            "Did you forget to call it? Use @resource('uri') instead of @resource"
        )

    def decorator(fn: _CallableT) -> _CallableT:
        # Check if this should be a template
        sig = inspect.signature(fn)
        has_uri_params = "{" in uri and "}" in uri
        has_func_params = bool(sig.parameters)

        if has_uri_params or has_func_params:
            # Check for Context parameter to exclude from validation
            context_param = find_context_parameter(fn)

            # Validate that URI params match function params (excluding context)
            uri_params = set(re.findall(r"{(\w+)}", uri))
            # We need to remove the context_param from the resource function if
            # there is any.
            func_params = {p for p in sig.parameters.keys() if p != context_param}

            if uri_params != func_params:
                raise ValueError(
                    f"Mismatch between URI parameters {uri_params} and function parameters {func_params}"
                )

            # Register as template
            self._resource_manager.add_template(
                fn=fn,
                uri_template=uri,
                name=name,
                title=title,
                description=description,
                mime_type=mime_type,
                icons=icons,
                annotations=annotations,
                meta=meta,
            )
        else:
            # Register as regular resource
            resource = FunctionResource.from_function(
                fn=fn,
                uri=uri,
                name=name,
                title=title,
                description=description,
                mime_type=mime_type,
                icons=icons,
                annotations=annotations,
                meta=meta,
            )
            self.add_resource(resource)
        return fn

    return decorator

add_prompt 

add_prompt(prompt: Prompt) -> None

Add a prompt to the server.

Parameters:

Name Type Description Default
prompt Prompt

A Prompt instance to add

 required
Source code in src/mcp/server/mcpserver/server.py 
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def add_prompt(self, prompt: Prompt) -> None:
    """Add a prompt to the server.

    Args:
        prompt: A Prompt instance to add
    """
    self._prompt_manager.add_prompt(prompt)

prompt 

prompt(
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    icons: list[Icon] | None = None,
) -> Callable[[_CallableT], _CallableT]

Decorator to register a prompt.

    Args:
        name: Optional name for the prompt (defaults to function name)
        title: Optional human-readable title for the prompt
        description: Optional description of what the prompt does
        icons: Optional list of icons for the prompt

    Example:
        ```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_file(path: str) -> list[Message]:
            content = await read_file(path)
            return [
                {
                    "role": "user",
                    "content": {
                        "type": "resource",
                        "resource": {
                            "uri": f"file://{path}",
                            "text": content
                        }
                    }
                }
            ]
        ```
Source code in src/mcp/server/mcpserver/server.py 
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def prompt(
    self,
    name: str | None = None,
    title: str | None = None,
    description: str | None = None,
    icons: list[Icon] | None = None,
) -> Callable[[_CallableT], _CallableT]:
    """Decorator to register a prompt.

    Args:
        name: Optional name for the prompt (defaults to function name)
        title: Optional human-readable title for the prompt
        description: Optional description of what the prompt does
        icons: Optional list of icons for the prompt

    Example:
        ```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:\n{schema}"
                }
            ]

        @server.prompt()
        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
                        }
                    }
                }
            ]
        ```
    """
    # Check if user passed function directly instead of calling decorator
    if callable(name):
        raise TypeError(
            "The @prompt decorator was used incorrectly. "
            "Did you forget to call it? Use @prompt() instead of @prompt"
        )

    def decorator(func: _CallableT) -> _CallableT:
        prompt = Prompt.from_function(func, name=name, title=title, description=description, icons=icons)
        self.add_prompt(prompt)
        return func

    return decorator

custom_route 

custom_route(
    path: str,
    methods: list[str],
    name: str | None = None,
    include_in_schema: bool = True,
)

Decorator to register a custom HTTP route on the MCP 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.

Routes using this decorator will not require authorization. It is intended for uses that are either a part of authorization flows or intended to be public such as health check endpoints.

Parameters:

Name Type Description Default
path str

URL path for the route (e.g., "/oauth/callback")

 required
methods list[str]

List of HTTP methods to support (e.g., ["GET", "POST"])

 required
name str | None

Optional name for the route (to reference this route with Starlette's reverse URL lookup feature)

 None
include_in_schema bool

Whether to include in OpenAPI schema, defaults to True

 True
Example 
@server.custom_route("/health", methods=["GET"])
async def health_check(request: Request) -> Response:
    return JSONResponse({"status": "ok"})
Source code in src/mcp/server/mcpserver/server.py 
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def custom_route(
    self,
    path: str,
    methods: list[str],
    name: str | None = None,
    include_in_schema: bool = True,
):
    """Decorator to register a custom HTTP route on the MCP 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.

    Routes using this decorator will not require authorization. It is intended
    for uses that are either a part of authorization flows or intended to be
    public such as health check endpoints.

    Args:
        path: URL path for the route (e.g., "/oauth/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

    Example:
        ```python
        @server.custom_route("/health", methods=["GET"])
        async def health_check(request: Request) -> Response:
            return JSONResponse({"status": "ok"})
        ```
    """

    def decorator(  # pragma: no cover
        func: Callable[[Request], Awaitable[Response]],
    ) -> Callable[[Request], Awaitable[Response]]:
        self._custom_starlette_routes.append(
            Route(path, endpoint=func, methods=methods, name=name, include_in_schema=include_in_schema)
        )
        return func

    return decorator  # pragma: no cover

run_stdio_async async 

run_stdio_async() -> None

Run the server using stdio transport.

Source code in src/mcp/server/mcpserver/server.py 
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async def run_stdio_async(self) -> None:
    """Run the server using stdio transport."""
    async with stdio_server() as (read_stream, write_stream):
        await self._lowlevel_server.run(
            read_stream,
            write_stream,
            self._lowlevel_server.create_initialization_options(),
        )

run_sse_async async 

run_sse_async(
    *,
    host: str = "127.0.0.1",
    port: int = 8000,
    sse_path: str = "/sse",
    message_path: str = "/messages/",
    transport_security: (
        TransportSecuritySettings | None
    ) = None
) -> None

Run the server using SSE transport.

Source code in src/mcp/server/mcpserver/server.py 
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async def run_sse_async(  # pragma: no cover
    self,
    *,
    host: str = "127.0.0.1",
    port: int = 8000,
    sse_path: str = "/sse",
    message_path: str = "/messages/",
    transport_security: TransportSecuritySettings | None = None,
) -> None:
    """Run the server using SSE transport."""
    import uvicorn

    starlette_app = self.sse_app(
        sse_path=sse_path,
        message_path=message_path,
        transport_security=transport_security,
        host=host,
    )

    config = uvicorn.Config(
        starlette_app,
        host=host,
        port=port,
        log_level=self.settings.log_level.lower(),
    )
    server = uvicorn.Server(config)
    await server.serve()

run_streamable_http_async async 

run_streamable_http_async(
    *,
    host: str = "127.0.0.1",
    port: int = 8000,
    streamable_http_path: str = "/mcp",
    json_response: bool = False,
    stateless_http: bool = False,
    event_store: EventStore | None = None,
    retry_interval: int | None = None,
    transport_security: (
        TransportSecuritySettings | None
    ) = None
) -> None

Run the server using StreamableHTTP transport.

Source code in src/mcp/server/mcpserver/server.py 
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async def run_streamable_http_async(  # pragma: no cover
    self,
    *,
    host: str = "127.0.0.1",
    port: int = 8000,
    streamable_http_path: str = "/mcp",
    json_response: bool = False,
    stateless_http: bool = False,
    event_store: EventStore | None = None,
    retry_interval: int | None = None,
    transport_security: TransportSecuritySettings | None = None,
) -> None:
    """Run the server using StreamableHTTP transport."""
    import uvicorn

    starlette_app = self.streamable_http_app(
        streamable_http_path=streamable_http_path,
        json_response=json_response,
        stateless_http=stateless_http,
        event_store=event_store,
        retry_interval=retry_interval,
        transport_security=transport_security,
        host=host,
    )

    config = uvicorn.Config(
        starlette_app,
        host=host,
        port=port,
        log_level=self.settings.log_level.lower(),
    )
    server = uvicorn.Server(config)
    await server.serve()

sse_app 

sse_app(
    *,
    sse_path: str = "/sse",
    message_path: str = "/messages/",
    transport_security: (
        TransportSecuritySettings | None
    ) = None,
    host: str = "127.0.0.1"
) -> Starlette

Return an instance of the SSE server app.

Source code in src/mcp/server/mcpserver/server.py 
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def sse_app(
    self,
    *,
    sse_path: str = "/sse",
    message_path: str = "/messages/",
    transport_security: TransportSecuritySettings | None = None,
    host: str = "127.0.0.1",
) -> Starlette:
    """Return an instance of the SSE server app."""
    # Auto-enable DNS rebinding protection for localhost (IPv4 and IPv6)
    if transport_security is None and host in ("127.0.0.1", "localhost", "::1"):
        transport_security = TransportSecuritySettings(
            enable_dns_rebinding_protection=True,
            allowed_hosts=["127.0.0.1:*", "localhost:*", "[::1]:*"],
            allowed_origins=["http://127.0.0.1:*", "http://localhost:*", "http://[::1]:*"],
        )

    sse = SseServerTransport(message_path, security_settings=transport_security)

    async def handle_sse(scope: Scope, receive: Receive, send: Send):  # pragma: no cover
        # Add client ID from auth context into request context if available

        async with sse.connect_sse(scope, receive, send) as streams:
            await self._lowlevel_server.run(
                streams[0], streams[1], self._lowlevel_server.create_initialization_options()
            )
        return Response()

    # Create routes
    routes: list[Route | Mount] = []
    middleware: list[Middleware] = []
    required_scopes: list[str] = []

    # Set up auth if configured
    if self.settings.auth:  # pragma: no cover
        required_scopes = self.settings.auth.required_scopes or []

        # Add auth middleware if token verifier is available
        if self._token_verifier:
            middleware = [
                # extract auth info from request (but do not require it)
                Middleware(
                    AuthenticationMiddleware,
                    backend=BearerAuthBackend(self._token_verifier),
                ),
                # Add the auth context middleware to store
                # authenticated user in a contextvar
                Middleware(AuthContextMiddleware),
            ]

        # Add auth endpoints if auth server provider is configured
        if self._auth_server_provider:
            from mcp.server.auth.routes import create_auth_routes

            routes.extend(
                create_auth_routes(
                    provider=self._auth_server_provider,
                    issuer_url=self.settings.auth.issuer_url,
                    service_documentation_url=self.settings.auth.service_documentation_url,
                    client_registration_options=self.settings.auth.client_registration_options,
                    revocation_options=self.settings.auth.revocation_options,
                )
            )

    # When auth is configured, require authentication
    if self._token_verifier:  # pragma: no cover
        # Determine resource metadata URL
        resource_metadata_url = None
        if self.settings.auth and self.settings.auth.resource_server_url:
            from mcp.server.auth.routes import build_resource_metadata_url

            # Build compliant metadata URL for WWW-Authenticate header
            resource_metadata_url = build_resource_metadata_url(self.settings.auth.resource_server_url)

        # Auth is enabled, wrap the endpoints with RequireAuthMiddleware
        routes.append(
            Route(
                sse_path,
                endpoint=RequireAuthMiddleware(handle_sse, required_scopes, resource_metadata_url),
                methods=["GET"],
            )
        )
        routes.append(
            Mount(
                message_path,
                app=RequireAuthMiddleware(sse.handle_post_message, required_scopes, resource_metadata_url),
            )
        )
    else:
        # Auth is disabled, no need for RequireAuthMiddleware
        # Since handle_sse is an ASGI app, we need to create a compatible endpoint
        async def sse_endpoint(request: Request) -> Response:  # pragma: no cover
            # Convert the Starlette request to ASGI parameters
            return await handle_sse(request.scope, request.receive, request._send)  # type: ignore[reportPrivateUsage]

        routes.append(
            Route(
                sse_path,
                endpoint=sse_endpoint,
                methods=["GET"],
            )
        )
        routes.append(
            Mount(
                message_path,
                app=sse.handle_post_message,
            )
        )
    # Add protected resource metadata endpoint if configured as RS
    if self.settings.auth and self.settings.auth.resource_server_url:  # pragma: no cover
        from mcp.server.auth.routes import create_protected_resource_routes

        routes.extend(
            create_protected_resource_routes(
                resource_url=self.settings.auth.resource_server_url,
                authorization_servers=[self.settings.auth.issuer_url],
                scopes_supported=self.settings.auth.required_scopes,
            )
        )

    # mount these routes last, so they have the lowest route matching precedence
    routes.extend(self._custom_starlette_routes)

    # Create Starlette app with routes and middleware
    return Starlette(debug=self.settings.debug, routes=routes, middleware=middleware)

streamable_http_app 

streamable_http_app(
    *,
    streamable_http_path: str = "/mcp",
    json_response: bool = False,
    stateless_http: bool = False,
    event_store: EventStore | None = None,
    retry_interval: int | None = None,
    transport_security: (
        TransportSecuritySettings | None
    ) = None,
    host: str = "127.0.0.1"
) -> Starlette

Return an instance of the StreamableHTTP server app.

Source code in src/mcp/server/mcpserver/server.py 
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def streamable_http_app(
    self,
    *,
    streamable_http_path: str = "/mcp",
    json_response: bool = False,
    stateless_http: bool = False,
    event_store: EventStore | None = None,
    retry_interval: int | None = None,
    transport_security: TransportSecuritySettings | None = None,
    host: str = "127.0.0.1",
) -> Starlette:
    """Return an instance of the StreamableHTTP server app."""
    return self._lowlevel_server.streamable_http_app(
        streamable_http_path=streamable_http_path,
        json_response=json_response,
        stateless_http=stateless_http,
        event_store=event_store,
        retry_interval=retry_interval,
        transport_security=transport_security,
        host=host,
        auth=self.settings.auth,
        token_verifier=self._token_verifier,
        auth_server_provider=self._auth_server_provider,
        custom_starlette_routes=self._custom_starlette_routes,
        debug=self.settings.debug,
    )

list_prompts async 

list_prompts() -> list[Prompt]

List all available prompts.

Source code in src/mcp/server/mcpserver/server.py 
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async def list_prompts(self) -> list[MCPPrompt]:
    """List all available prompts."""
    prompts = self._prompt_manager.list_prompts()
    return [
        MCPPrompt(
            name=prompt.name,
            title=prompt.title,
            description=prompt.description,
            arguments=[
                MCPPromptArgument(
                    name=arg.name,
                    description=arg.description,
                    required=arg.required,
                )
                for arg in (prompt.arguments or [])
            ],
            icons=prompt.icons,
        )
        for prompt in prompts
    ]

get_prompt async 

get_prompt(
    name: str,
    arguments: dict[str, Any] | None = None,
    context: Context[LifespanResultT, Any] | None = None,
) -> GetPromptResult

Get a prompt by name with arguments.

Source code in src/mcp/server/mcpserver/server.py 
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async def get_prompt(
    self, name: str, arguments: dict[str, Any] | None = None, context: Context[LifespanResultT, Any] | None = None
) -> GetPromptResult:
    """Get a prompt by name with arguments."""
    if context is None:
        context = Context(mcp_server=self)
    try:
        prompt = self._prompt_manager.get_prompt(name)
        if not prompt:
            raise ValueError(f"Unknown prompt: {name}")

        messages = await prompt.render(arguments, context)

        return GetPromptResult(
            description=prompt.description,
            messages=pydantic_core.to_jsonable_python(messages),
        )
    except Exception as e:
        logger.exception(f"Error getting prompt {name}")
        raise ValueError(str(e)) from e

Audio

Helper class for returning audio from tools.

Source code in src/mcp/server/mcpserver/utilities/types.py 
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class Audio:
    """Helper class for returning audio from tools."""

    def __init__(
        self,
        path: str | Path | None = None,
        data: bytes | None = None,
        format: str | None = None,
    ):
        if not bool(path) ^ bool(data):  # pragma: no cover
            raise ValueError("Either path or data can be provided")

        self.path = Path(path) if path else None
        self.data = data
        self._format = format
        self._mime_type = self._get_mime_type()

    def _get_mime_type(self) -> str:
        """Get MIME type from format or guess from file extension."""
        if self._format:  # pragma: no cover
            return f"audio/{self._format.lower()}"

        if self.path:
            suffix = self.path.suffix.lower()
            return {
                ".wav": "audio/wav",
                ".mp3": "audio/mpeg",
                ".ogg": "audio/ogg",
                ".flac": "audio/flac",
                ".aac": "audio/aac",
                ".m4a": "audio/mp4",
            }.get(suffix, "application/octet-stream")
        return "audio/wav"  # pragma: no cover  # default for raw binary data

    def to_audio_content(self) -> AudioContent:
        """Convert to MCP AudioContent."""
        if self.path:
            with open(self.path, "rb") as f:
                data = base64.b64encode(f.read()).decode()
        elif self.data is not None:  # pragma: no cover
            data = base64.b64encode(self.data).decode()
        else:  # pragma: no cover
            raise ValueError("No audio data available")

        return AudioContent(type="audio", data=data, mime_type=self._mime_type)

to_audio_content 

to_audio_content() -> AudioContent

Convert to MCP AudioContent.

Source code in src/mcp/server/mcpserver/utilities/types.py 
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def to_audio_content(self) -> AudioContent:
    """Convert to MCP AudioContent."""
    if self.path:
        with open(self.path, "rb") as f:
            data = base64.b64encode(f.read()).decode()
    elif self.data is not None:  # pragma: no cover
        data = base64.b64encode(self.data).decode()
    else:  # pragma: no cover
        raise ValueError("No audio data available")

    return AudioContent(type="audio", data=data, mime_type=self._mime_type)

Image

Helper class for returning images from tools.

Source code in src/mcp/server/mcpserver/utilities/types.py 
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class Image:
    """Helper class for returning images from tools."""

    def __init__(
        self,
        path: str | Path | None = None,
        data: bytes | None = None,
        format: str | None = None,
    ):
        if path is None and data is None:  # pragma: no cover
            raise ValueError("Either path or data must be provided")
        if path is not None and data is not None:  # pragma: no cover
            raise ValueError("Only one of path or data can be provided")

        self.path = Path(path) if path else None
        self.data = data
        self._format = format
        self._mime_type = self._get_mime_type()

    def _get_mime_type(self) -> str:
        """Get MIME type from format or guess from file extension."""
        if self._format:  # pragma: no cover
            return f"image/{self._format.lower()}"

        if self.path:
            suffix = self.path.suffix.lower()
            return {
                ".png": "image/png",
                ".jpg": "image/jpeg",
                ".jpeg": "image/jpeg",
                ".gif": "image/gif",
                ".webp": "image/webp",
            }.get(suffix, "application/octet-stream")
        return "image/png"  # pragma: no cover  # default for raw binary data

    def to_image_content(self) -> ImageContent:
        """Convert to MCP ImageContent."""
        if self.path:
            with open(self.path, "rb") as f:
                data = base64.b64encode(f.read()).decode()
        elif self.data is not None:  # pragma: no cover
            data = base64.b64encode(self.data).decode()
        else:  # pragma: no cover
            raise ValueError("No image data available")

        return ImageContent(type="image", data=data, mime_type=self._mime_type)

to_image_content 

to_image_content() -> ImageContent

Convert to MCP ImageContent.

Source code in src/mcp/server/mcpserver/utilities/types.py 
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def to_image_content(self) -> ImageContent:
    """Convert to MCP ImageContent."""
    if self.path:
        with open(self.path, "rb") as f:
            data = base64.b64encode(f.read()).decode()
    elif self.data is not None:  # pragma: no cover
        data = base64.b64encode(self.data).decode()
    else:  # pragma: no cover
        raise ValueError("No image data available")

    return ImageContent(type="image", data=data, mime_type=self._mime_type)