kotlin-sdk-client/io.modelcontextprotocol.kotlin.sdk.client/Client

Client

open class Client(clientInfo: Implementation, options: ClientOptions = ClientOptions()) : Protocol(source)

An MCP client on top of a pluggable transport.

The client automatically performs the initialization handshake with the server when connect is called. After initialization, serverCapabilities and serverVersion provide details about the connected server.

You can extend this class with custom request/notification/result types if needed.

Parameters

clientInfo

Information about the client implementation (name, version).

options

Configuration options for this client.

Constructors

Client

constructor(clientInfo: Implementation, options: ClientOptions = ClientOptions())

Properties

fallbackNotificationHandler

var fallbackNotificationHandler: suspend (notification: JSONRPCNotification) -> Unit?

fallbackRequestHandler

var fallbackRequestHandler: suspend (request: JSONRPCRequest, extra: RequestHandlerExtra) -> RequestResult??

notificationHandlers

val notificationHandlers: Map<String, suspend (notification: JSONRPCNotification) -> Unit>

progressHandlers

val progressHandlers: Map<RequestId, ProgressCallback>

requestHandlers

val requestHandlers: Map<String, suspend (request: JSONRPCRequest, extra: RequestHandlerExtra) -> RequestResult?>

responseHandlers

val responseHandlers: Map<RequestId, (response: JSONRPCResponse?, error: Exception?) -> Unit>

serverCapabilities

var serverCapabilities: ServerCapabilities?

Retrieves the server's reported capabilities after the initialization process completes.

serverVersion

var serverVersion: Implementation?

Retrieves the server's reported version information after initialization.

transport

var transport: Transport?

Functions

addRoot

fun addRoot(uri: String, name: String)

Registers a single root.

addRoots

fun addRoots(rootsToAdd: List<Root>)

Registers multiple roots at once.

assertRequestHandlerCapability

open override fun assertRequestHandlerCapability(method: Method)

callTool

suspend fun callTool(request: CallToolRequest, compatibility: Boolean = false, options: RequestOptions? = null): CallToolResultBase?

Calls a tool on the server using a CallToolRequest object.

suspend fun callTool(name: String, arguments: Map<String, Any?>, compatibility: Boolean = false, options: RequestOptions? = null): CallToolResultBase?

Calls a tool on the server by name, passing the specified arguments.

suspend fun close()

complete

suspend fun complete(params: CompleteRequest, options: RequestOptions? = null): CompleteResult

Sends a completion request to the server, typically to generate or complete some content.

connect

open suspend override fun connect(transport: Transport)

Connects the client to the given transport, performing the initialization handshake with the server.

getPrompt

suspend fun getPrompt(request: GetPromptRequest, options: RequestOptions? = null): GetPromptResult

Retrieves a prompt by name from the server.

listPrompts

suspend fun listPrompts(request: ListPromptsRequest = ListPromptsRequest(), options: RequestOptions? = null): ListPromptsResult

Lists all available prompts from the server.

listResources

suspend fun listResources(request: ListResourcesRequest = ListResourcesRequest(), options: RequestOptions? = null): ListResourcesResult

Lists all available resources from the server.

listResourceTemplates

suspend fun listResourceTemplates(request: ListResourceTemplatesRequest, options: RequestOptions? = null): ListResourceTemplatesResult

Lists resource templates available on the server.

listTools

suspend fun listTools(request: ListToolsRequest = ListToolsRequest(), options: RequestOptions? = null): ListToolsResult

Lists all available tools on the server.

notification

suspend fun notification(notification: Notification)

onClose

open fun onClose()

onError

open fun onError(error: Throwable)

ping

suspend fun ping(options: RequestOptions? = null): EmptyRequestResult

Sends a ping request to the server to check connectivity.

readResource

suspend fun readResource(request: ReadResourceRequest, options: RequestOptions? = null): ReadResourceResult

Reads a resource from the server by its URI.

removeNotificationHandler

fun removeNotificationHandler(method: Method)

removeRequestHandler

fun removeRequestHandler(method: Method)

removeRoot

fun removeRoot(uri: String): Boolean

Removes a single root by URI.

removeRoots

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

Removes multiple roots at once.

request

suspend fun <T : RequestResult> request(request: Request, options: RequestOptions?): T

sendRootsListChanged

suspend fun sendRootsListChanged()

Notifies the server that the list of roots has changed. Typically used if the client is managing some form of hierarchical structure.

setElicitationHandler

fun setElicitationHandler(handler: (CreateElicitationRequest) -> CreateElicitationResult)

Sets the elicitation handler.

setLoggingLevel

suspend fun setLoggingLevel(level: LoggingLevel, options: RequestOptions? = null): EmptyRequestResult

Sets the logging level on the server.

setNotificationHandler

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

setRequestHandler

inline fun <T : Request> setRequestHandler(method: Method, noinline block: suspend (T, RequestHandlerExtra) -> RequestResult?)

subscribeResource

suspend fun subscribeResource(request: SubscribeRequest, options: RequestOptions? = null): EmptyRequestResult

Subscribes to resource changes on the server.

unsubscribeResource

suspend fun unsubscribeResource(request: UnsubscribeRequest, options: RequestOptions? = null): EmptyRequestResult

Unsubscribes from resource changes on the server.