kotlin-sdk-server/io.modelcontextprotocol.kotlin.sdk.server/Server

Server

open class Server(serverInfo: Implementation, options: ServerOptions, instructionsProvider: () -> String? = null, block: Server.() -> Unit = {})(source)

An MCP server is responsible for storing features and handling new connections.

This server automatically responds to the initialization flow as initiated by the client. You can register tools, prompts, and resources using addTool, addPrompt, and addResource. The server will then automatically handle listing and retrieval requests from the client.

In case the server supports feature list notification or resource substitution, the server will automatically send notifications for all connected clients. Currently, after subscription to a resource, the server will NOT send the subscription confirmation as this response schema is not defined in the protocol.

Parameters

serverInfo

Information about this server implementation (name, version).

options

Configuration options for the server.

instructionsProvider

Optional provider for instructions from the server to the client about how to use this server. The provider is called each time a new session is started to support dynamic instructions.

block

A block to configure the mcp server.

Constructors

Server

constructor(serverInfo: Implementation, options: ServerOptions, instructionsProvider: () -> String? = null, block: Server.() -> Unit = {})

constructor(serverInfo: Implementation, options: ServerOptions, instructions: String, block: Server.() -> Unit = {})

Alternative constructor that provides the instructions directly as a string.

Properties

prompts

val prompts: Map<String, RegisteredPrompt>

Provides a snapshot of all prompts currently registered in the server

resources

val resources: Map<String, RegisteredResource>

Provides a snapshot of all resources currently registered in the server

sessions

val sessions: Map<ServerSessionKey, ServerSession>

Provides a snapshot of all sessions currently registered in the server

tools

val tools: Map<String, RegisteredTool>

Provides a snapshot of all tools currently registered in the server

Functions

addPrompt

fun addPrompt(prompt: Prompt, promptProvider: suspend (GetPromptRequest) -> GetPromptResult)

Registers a single prompt. The client can then retrieve the prompt.

fun addPrompt(name: String, description: String? = null, arguments: List<PromptArgument>? = null, promptProvider: suspend (GetPromptRequest) -> GetPromptResult)

Registers a single prompt by constructing a Prompt from given parameters.

addPrompts

fun addPrompts(promptsToAdd: List<RegisteredPrompt>)

Registers multiple prompts at once.

addResource

fun addResource(uri: String, name: String, description: String, mimeType: String = "text/html", readHandler: suspend (ReadResourceRequest) -> ReadResourceResult)

Registers a single resource. The client can then read the resource content.

addResources

fun addResources(resourcesToAdd: List<RegisteredResource>)

Registers multiple resources at once.

addTool

fun addTool(tool: Tool, handler: suspend (CallToolRequest) -> CallToolResult)

fun addTool(name: String, description: String, inputSchema: ToolSchema = ToolSchema(), title: String? = null, outputSchema: ToolSchema? = null, toolAnnotations: ToolAnnotations? = null, meta: JsonObject? = null, handler: suspend (CallToolRequest) -> CallToolResult)

Registers a single tool. The client can then call this tool.

addTools

fun addTools(toolsToAdd: List<RegisteredTool>)

Registers multiple tools at once.

suspend fun close()

connect

suspend fun ~~connect~~(transport: Transport): ServerSession

Starts a new server session with the given transport and initializes internal request handlers based on the server's capabilities.

createElicitation

suspend fun createElicitation(sessionId: String, message: String, requestedSchema: ElicitRequestParams.RequestedSchema, options: RequestOptions? = null): ElicitResult

Triggers ServerSession.createElicitation request for session by provided sessionId.

createMessage

suspend fun createMessage(sessionId: String, params: CreateMessageRequest, options: RequestOptions? = null): CreateMessageResult

Triggers ServerSession.createMessage request for session by provided sessionId.

createSession

suspend fun createSession(transport: Transport): ServerSession

Starts a new server session with the given transport and initializes internal request handlers based on the server's capabilities.

listRoots

suspend fun listRoots(sessionId: String, params: JsonObject = EmptyJsonObject, options: RequestOptions? = null): ListRootsResult

Triggers ServerSession.listRoots request for session by provided sessionId.

onClose

fun onClose(block: () -> Unit)

Registers a callback to be invoked when the server connection is closing.

onConnect

fun onConnect(block: () -> Unit)

Registers a callback to be invoked when the new server session connected.

onInitialized

fun ~~onInitialized~~(block: () -> Unit)

Registers a callback to be invoked when the server has completed initialization.

ping

suspend fun ping(sessionId: String): EmptyResult

Triggers ServerSession.ping request for session by provided sessionId.

removeNotificationHandler

fun removeNotificationHandler(method: Method)

fun removeNotificationHandler(sessionId: String, method: Method)

removePrompt

fun removePrompt(name: String): Boolean

Removes a single prompt by name.

removePrompts

fun removePrompts(promptNames: List<String>): Int

Removes multiple prompts at once.

removeResource

fun removeResource(uri: String): Boolean

Removes a single resource by URI.

removeResources

fun removeResources(uris: List<String>): Int

Removes multiple resources at once.

removeTool

fun removeTool(name: String): Boolean

Removes a single tool by name.

removeTools

fun removeTools(toolNames: List<String>): Int

Removes multiple tools at once.

sendLoggingMessage

suspend fun sendLoggingMessage(sessionId: String, notification: LoggingMessageNotification)

Triggers ServerSession.sendLoggingMessage for session by provided sessionId.

sendPromptListChanged

suspend fun sendPromptListChanged(sessionId: String)

Triggers ServerSession.sendPromptListChanged for session by provided sessionId.

sendResourceListChanged

suspend fun sendResourceListChanged(sessionId: String)

Triggers ServerSession.sendResourceListChanged for session by provided sessionId.

sendResourceUpdated

suspend fun sendResourceUpdated(sessionId: String, notification: ResourceUpdatedNotification)

Triggers ServerSession.sendResourceUpdated for session by provided sessionId.

sendToolListChanged

suspend fun sendToolListChanged(sessionId: String)

Triggers ServerSession.sendToolListChanged for session by provided sessionId.

setNotificationHandler

fun <T : Notification> setNotificationHandler(method: Method, handler: (notification: T) -> Deferred<Unit>)

fun <T : Notification> setNotificationHandler(sessionId: String, method: Method, handler: (notification: T) -> Deferred<Unit>)