Struct Client 

pub struct Client<T: Transport, H: ClientHandler = NoOpHandler> { /* private fields */ }

An MCP client connected to a server.

The client provides methods for interacting with MCP servers:

• Tools: list_tools(), call_tool()
• Resources: list_resources(), read_resource()
• Prompts: list_prompts(), get_prompt()
• Tasks: list_tasks(), get_task(), cancel_task()

The client also handles server-initiated requests (sampling, elicitation) by delegating to a ClientHandler implementation.

Example

use mcpkit_client::ClientBuilder;
use mcpkit_transport::SpawnedTransport;

let transport = SpawnedTransport::spawn("my-server", &[] as &[&str]).await?;
let client = ClientBuilder::new()
    .name("my-client")
    .version("1.0.0")
    .build(transport)
    .await?;

let tools = client.list_tools().await?;

Implementations

impl<T: Transport + 'static, H: ClientHandler + 'static> Client<T, H>

pub const fn server_info(&self) -> &ServerInfo

Get the server information.

pub const fn server_capabilities(&self) -> &ServerCapabilities

Get the server capabilities.

pub fn protocol_version(&self) -> ProtocolVersion

Get the negotiated protocol version.

Use this for feature detection. For example:

if client.protocol_version().supports_tasks() {
    // Use task-related features
}

pub const fn client_info(&self) -> &ClientInfo

Get the client information.

pub const fn client_capabilities(&self) -> &ClientCapabilities

Get the client capabilities.

pub fn instructions(&self) -> Option<&str>

Get the server instructions, if provided.

pub const fn has_tools(&self) -> bool

Check if the server supports tools.

pub const fn has_resources(&self) -> bool

Check if the server supports resources.

pub const fn has_prompts(&self) -> bool

Check if the server supports prompts.

pub const fn has_tasks(&self) -> bool

Check if the server supports tasks.

pub const fn has_completions(&self) -> bool

Check if the server supports completions.

pub fn is_connected(&self) -> bool

Check if the client is still connected.

pub async fn list_tools(&self) -> Result<Vec<Tool>, McpError>

List all available tools.

Errors

Returns an error if tools are not supported or the request fails.

pub async fn list_tools_paginated( &self, cursor: Option<&str>, ) -> Result<ListToolsResult, McpError>

List tools with pagination.

Errors

Returns an error if tools are not supported or the request fails.

pub async fn call_tool( &self, name: impl Into<String>, arguments: Value, ) -> Result<CallToolResult, McpError>

Call a tool by name.

Arguments

• name - The name of the tool to call
• arguments - The arguments to pass to the tool (as JSON)

Errors

Returns an error if tools are not supported or the call fails.

pub async fn list_resources(&self) -> Result<Vec<Resource>, McpError>

List all available resources.

Errors

Returns an error if resources are not supported or the request fails.

pub async fn list_resources_paginated( &self, cursor: Option<&str>, ) -> Result<ListResourcesResult, McpError>

List resources with pagination.

Errors

Returns an error if resources are not supported or the request fails.

pub async fn list_resource_templates( &self, ) -> Result<Vec<ResourceTemplate>, McpError>

List resource templates.

Errors

Returns an error if resources are not supported or the request fails.

pub async fn read_resource( &self, uri: impl Into<String>, ) -> Result<Vec<ResourceContents>, McpError>

Read a resource by URI.

Errors

Returns an error if resources are not supported or the read fails.

pub async fn list_prompts(&self) -> Result<Vec<Prompt>, McpError>

List all available prompts.

Errors

Returns an error if prompts are not supported or the request fails.

pub async fn list_prompts_paginated( &self, cursor: Option<&str>, ) -> Result<ListPromptsResult, McpError>

List prompts with pagination.

Errors

Returns an error if prompts are not supported or the request fails.

pub async fn get_prompt( &self, name: impl Into<String>, arguments: Option<Map<String, Value>>, ) -> Result<GetPromptResult, McpError>

Get a prompt by name, optionally with arguments.

Errors

Returns an error if prompts are not supported or the get fails.

pub async fn list_tasks(&self) -> Result<Vec<TaskSummary>, McpError>

List all tasks.

Errors

Returns an error if tasks are not supported or the request fails.

pub async fn list_tasks_filtered( &self, status: Option<TaskStatus>, cursor: Option<&str>, ) -> Result<ListTasksResult, McpError>

List tasks with optional status filter and pagination.

Errors

Returns an error if tasks are not supported or the request fails.

pub async fn get_task(&self, id: impl Into<String>) -> Result<Task, McpError>

Get a task by ID.

Errors

Returns an error if tasks are not supported or the task is not found.

pub async fn cancel_task(&self, id: impl Into<String>) -> Result<(), McpError>

Cancel a running task.

Errors

Returns an error if tasks are not supported, cancellation is not supported, or the task is not found.

pub async fn complete_prompt_argument( &self, prompt_name: impl Into<String>, argument_name: impl Into<String>, current_value: impl Into<String>, ) -> Result<CompleteResult, McpError>

Get completions for a prompt argument.

Arguments

• prompt_name - The name of the prompt
• argument_name - The name of the argument to complete
• current_value - The current partial value being typed

Errors

Returns an error if completions are not supported or the request fails.

pub async fn complete_resource_argument( &self, resource_uri: impl Into<String>, argument_name: impl Into<String>, current_value: impl Into<String>, ) -> Result<CompleteResult, McpError>

Get completions for a resource argument.

Arguments

• resource_uri - The URI of the resource
• argument_name - The name of the argument to complete
• current_value - The current partial value being typed

Errors

Returns an error if completions are not supported or the request fails.

pub async fn subscribe_resource( &self, uri: impl Into<String>, ) -> Result<(), McpError>

Subscribe to updates for a resource.

When subscribed, the server will send notifications/resources/updated when the resource changes.

Errors

Returns an error if resource subscriptions are not supported or the request fails.

pub async fn unsubscribe_resource( &self, uri: impl Into<String>, ) -> Result<(), McpError>

Unsubscribe from updates for a resource.

Errors

Returns an error if resource subscriptions are not supported or the request fails.

pub async fn ping(&self) -> Result<(), McpError>

Ping the server.

Errors

Returns an error if the ping fails.

pub async fn close(self) -> Result<(), McpError>

Close the connection gracefully.

Errors

Returns an error if the close fails.