McpAsyncClient (solon-ai-mcp 3.2.1-RC API)

java.lang.Object
- io.modelcontextprotocol.client.McpAsyncClient

```
public class McpAsyncClient
extends Object
```
The Model Context Protocol (MCP) client implementation that provides asynchronous communication with MCP servers using Project Reactor's Mono and Flux types.
This client implements the MCP specification, enabling AI models to interact with external tools and resources through a standardized interface. Key features include:
- Asynchronous communication using reactive programming patterns
- Tool discovery and invocation for server-provided functionality
- Resource access and management with URI-based addressing
- Prompt template handling for standardized AI interactions
- Real-time notifications for tools, resources, and prompts changes
- Structured logging with configurable severity levels
- Message sampling for AI model interactions
The client follows a lifecycle:
1. Initialization - Establishes connection and negotiates capabilities
2. Normal Operation - Handles requests and notifications
3. Graceful Shutdown - Ensures clean connection termination
This implementation uses Project Reactor for non-blocking operations, making it suitable for high-throughput scenarios and reactive applications. All operations return Mono or Flux types that can be composed into reactive pipelines.
Author:

Dariusz Jędrzejczyk, Christian Tzolov

See Also:

McpClient, McpSchema, McpClientSession

Field Summary

Fields
Modifier and Type Field and Description

protected reactor.core.publisher.Sinks.One<McpSchema.InitializeResult> initializedSink

Fields
Modifier and Type	Field and Description
`protected reactor.core.publisher.Sinks.One<McpSchema.InitializeResult>`	`initializedSink`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`reactor.core.publisher.Mono<Void>`	`addRoot(McpSchema.Root root)` Adds a new root to the client's root list.
`reactor.core.publisher.Mono<McpSchema.CallToolResult>`	`callTool(McpSchema.CallToolRequest callToolRequest)` Calls a tool provided by the server.
`void`	`close()` Closes the client connection immediately.
`reactor.core.publisher.Mono<Void>`	`closeGracefully()` Gracefully closes the client connection.
`McpSchema.ClientCapabilities`	`getClientCapabilities()` Get the client capabilities that define the supported features and functionality.
`McpSchema.Implementation`	`getClientInfo()` Get the client implementation information.
`reactor.core.publisher.Mono<McpSchema.GetPromptResult>`	`getPrompt(McpSchema.GetPromptRequest getPromptRequest)` Retrieves a specific prompt by its ID.
`McpSchema.ServerCapabilities`	`getServerCapabilities()` Get the server capabilities that define the supported features and functionality.
`McpSchema.Implementation`	`getServerInfo()` Get the server implementation information.
`reactor.core.publisher.Mono<McpSchema.InitializeResult>`	`initialize()` The initialization phase MUST be the first interaction between client and server.
`boolean`	`isInitialized()` Check if the client-server connection is initialized.
`reactor.core.publisher.Mono<McpSchema.ListPromptsResult>`	`listPrompts()` Retrieves the list of all prompts provided by the server.
`reactor.core.publisher.Mono<McpSchema.ListPromptsResult>`	`listPrompts(String cursor)` Retrieves a paginated list of prompts provided by the server.
`reactor.core.publisher.Mono<McpSchema.ListResourcesResult>`	`listResources()` Retrieves the list of all resources provided by the server.
`reactor.core.publisher.Mono<McpSchema.ListResourcesResult>`	`listResources(String cursor)` Retrieves a paginated list of resources provided by the server.
`reactor.core.publisher.Mono<McpSchema.ListResourceTemplatesResult>`	`listResourceTemplates()` Retrieves the list of all resource templates provided by the server.
`reactor.core.publisher.Mono<McpSchema.ListResourceTemplatesResult>`	`listResourceTemplates(String cursor)` Retrieves a paginated list of resource templates provided by the server.
`reactor.core.publisher.Mono<McpSchema.ListToolsResult>`	`listTools()` Retrieves the list of all tools provided by the server.
`reactor.core.publisher.Mono<McpSchema.ListToolsResult>`	`listTools(String cursor)` Retrieves a paginated list of tools provided by the server.
`reactor.core.publisher.Mono<Object>`	`ping()` Sends a ping request to the server.
`reactor.core.publisher.Mono<McpSchema.ReadResourceResult>`	`readResource(McpSchema.ReadResourceRequest readResourceRequest)` Reads the content of a specific resource identified by the provided request.
`reactor.core.publisher.Mono<McpSchema.ReadResourceResult>`	`readResource(McpSchema.Resource resource)` Reads the content of a specific resource identified by the provided Resource object.
`reactor.core.publisher.Mono<Void>`	`removeRoot(String rootUri)` Removes a root from the client's root list.
`reactor.core.publisher.Mono<Void>`	`rootsListChangedNotification()` Manually sends a roots/list_changed notification.
`reactor.core.publisher.Mono<Void>`	`setLoggingLevel(McpSchema.LoggingLevel loggingLevel)` Sets the minimum logging level for messages received from the server.
`reactor.core.publisher.Mono<Void>`	`subscribeResource(McpSchema.SubscribeRequest subscribeRequest)` Subscribes to changes in a specific resource.
`reactor.core.publisher.Mono<Void>`	`unsubscribeResource(McpSchema.UnsubscribeRequest unsubscribeRequest)` Cancels an existing subscription to a resource.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - initializedSink
```
protected final reactor.core.publisher.Sinks.One<McpSchema.InitializeResult> initializedSink
```
- Method Detail
  - getServerCapabilities
```
public McpSchema.ServerCapabilities getServerCapabilities()
```
    Get the server capabilities that define the supported features and functionality.
    
    Returns:
    
    The server capabilities
  - getServerInfo
```
public McpSchema.Implementation getServerInfo()
```
    Get the server implementation information.
    
    Returns:
    
    The server implementation details
  - isInitialized
```
public boolean isInitialized()
```
    Check if the client-server connection is initialized.
    
    Returns:
    
    true if the client-server connection is initialized
  - getClientCapabilities
```
public McpSchema.ClientCapabilities getClientCapabilities()
```
    Get the client capabilities that define the supported features and functionality.
    
    Returns:
    
    The client capabilities
  - getClientInfo
```
public McpSchema.Implementation getClientInfo()
```
    Get the client implementation information.
    
    Returns:
    
    The client implementation details
  - close
```
public void close()
```
    Closes the client connection immediately.
  - closeGracefully
```
public reactor.core.publisher.Mono<Void> closeGracefully()
```
    Gracefully closes the client connection.
    
    Returns:
    
    A Mono that completes when the connection is closed
  - initialize
```
public reactor.core.publisher.Mono<McpSchema.InitializeResult> initialize()
```
    The initialization phase MUST be the first interaction between client and server. During this phase, the client and server:
    - Establish protocol version compatibility
    - Exchange and negotiate capabilities
    - Share implementation details
    The client MUST initiate this phase by sending an initialize request containing: The protocol version the client supports, client's capabilities and clients implementation information.
    The server MUST respond with its own capabilities and information.
    After successful initialization, the client MUST send an initialized notification to indicate it is ready to begin normal operations.
    Returns:
    
    the initialize result.
    
    See Also:
    
    MCP Initialization Spec
  - ping
```
public reactor.core.publisher.Mono<Object> ping()
```
    Sends a ping request to the server.
    
    Returns:
    
    A Mono that completes with the server's ping response
  - addRoot
```
public reactor.core.publisher.Mono<Void> addRoot(McpSchema.Root root)
```
    Adds a new root to the client's root list.
    
    Parameters:
    
    root - The root to add.
    
    Returns:
    
    A Mono that completes when the root is added and notifications are sent.
  - removeRoot
```
public reactor.core.publisher.Mono<Void> removeRoot(String rootUri)
```
    Removes a root from the client's root list.
    
    Parameters:
    
    rootUri - The URI of the root to remove.
    
    Returns:
    
    A Mono that completes when the root is removed and notifications are sent.
  - rootsListChangedNotification
```
public reactor.core.publisher.Mono<Void> rootsListChangedNotification()
```
    Manually sends a roots/list_changed notification. The addRoot and removeRoot methods automatically send the roots/list_changed notification if the client is in an initialized state.
    
    Returns:
    
    A Mono that completes when the notification is sent.
  - callTool
```
public reactor.core.publisher.Mono<McpSchema.CallToolResult> callTool(McpSchema.CallToolRequest callToolRequest)
```
    Calls a tool provided by the server. Tools enable servers to expose executable functionality that can interact with external systems, perform computations, and take actions in the real world.
    
    Parameters:
    
    callToolRequest - The request containing the tool name and input parameters.
    
    Returns:
    
    A Mono that emits the result of the tool call, including the output and any errors.
    
    See Also:
    
    McpSchema.CallToolRequest, McpSchema.CallToolResult, listTools()
  - listTools
```
public reactor.core.publisher.Mono<McpSchema.ListToolsResult> listTools()
```
    Retrieves the list of all tools provided by the server.
    
    Returns:
    
    A Mono that emits the list of tools result.
  - listTools
```
public reactor.core.publisher.Mono<McpSchema.ListToolsResult> listTools(String cursor)
```
    Retrieves a paginated list of tools provided by the server.
    
    Parameters:
    
    cursor - Optional pagination cursor from a previous list request
    
    Returns:
    
    A Mono that emits the list of tools result
  - listResources
```
public reactor.core.publisher.Mono<McpSchema.ListResourcesResult> listResources()
```
    Retrieves the list of all resources provided by the server. Resources represent any kind of UTF-8 encoded data that an MCP server makes available to clients, such as database records, API responses, log files, and more.
    
    Returns:
    
    A Mono that completes with the list of resources result.
    
    See Also:
    
    McpSchema.ListResourcesResult, readResource(McpSchema.Resource)
  - listResources
```
public reactor.core.publisher.Mono<McpSchema.ListResourcesResult> listResources(String cursor)
```
    Retrieves a paginated list of resources provided by the server. Resources represent any kind of UTF-8 encoded data that an MCP server makes available to clients, such as database records, API responses, log files, and more.
    
    Parameters:
    
    cursor - Optional pagination cursor from a previous list request.
    
    Returns:
    
    A Mono that completes with the list of resources result.
    
    See Also:
    
    McpSchema.ListResourcesResult, readResource(McpSchema.Resource)
  - readResource
```
public reactor.core.publisher.Mono<McpSchema.ReadResourceResult> readResource(McpSchema.Resource resource)
```
    Reads the content of a specific resource identified by the provided Resource object. This method fetches the actual data that the resource represents.
    
    Parameters:
    
    resource - The resource to read, containing the URI that identifies the resource.
    
    Returns:
    
    A Mono that completes with the resource content.
    
    See Also:
    
    McpSchema.Resource, McpSchema.ReadResourceResult
  - readResource
```
public reactor.core.publisher.Mono<McpSchema.ReadResourceResult> readResource(McpSchema.ReadResourceRequest readResourceRequest)
```
    Reads the content of a specific resource identified by the provided request. This method fetches the actual data that the resource represents.
    
    Parameters:
    
    readResourceRequest - The request containing the URI of the resource to read
    
    Returns:
    
    A Mono that completes with the resource content.
    
    See Also:
    
    McpSchema.ReadResourceRequest, McpSchema.ReadResourceResult
  - listResourceTemplates
```
public reactor.core.publisher.Mono<McpSchema.ListResourceTemplatesResult> listResourceTemplates()
```
    Retrieves the list of all resource templates provided by the server. Resource templates allow servers to expose parameterized resources using URI templates, enabling dynamic resource access based on variable parameters.
    
    Returns:
    
    A Mono that completes with the list of resource templates result.
    
    See Also:
    
    McpSchema.ListResourceTemplatesResult
  - listResourceTemplates
```
public reactor.core.publisher.Mono<McpSchema.ListResourceTemplatesResult> listResourceTemplates(String cursor)
```
    Retrieves a paginated list of resource templates provided by the server. Resource templates allow servers to expose parameterized resources using URI templates, enabling dynamic resource access based on variable parameters.
    
    Parameters:
    
    cursor - Optional pagination cursor from a previous list request.
    
    Returns:
    
    A Mono that completes with the list of resource templates result.
    
    See Also:
    
    McpSchema.ListResourceTemplatesResult
  - subscribeResource
```
public reactor.core.publisher.Mono<Void> subscribeResource(McpSchema.SubscribeRequest subscribeRequest)
```
    Subscribes to changes in a specific resource. When the resource changes on the server, the client will receive notifications through the resources change notification handler.
    
    Parameters:
    
    subscribeRequest - The subscribe request containing the URI of the resource.
    
    Returns:
    
    A Mono that completes when the subscription is complete.
    
    See Also:
    
    McpSchema.SubscribeRequest, unsubscribeResource(McpSchema.UnsubscribeRequest)
  - unsubscribeResource
```
public reactor.core.publisher.Mono<Void> unsubscribeResource(McpSchema.UnsubscribeRequest unsubscribeRequest)
```
    Cancels an existing subscription to a resource. After unsubscribing, the client will no longer receive notifications when the resource changes.
    
    Parameters:
    
    unsubscribeRequest - The unsubscribe request containing the URI of the resource.
    
    Returns:
    
    A Mono that completes when the unsubscription is complete.
    
    See Also:
    
    McpSchema.UnsubscribeRequest, subscribeResource(McpSchema.SubscribeRequest)
  - listPrompts
```
public reactor.core.publisher.Mono<McpSchema.ListPromptsResult> listPrompts()
```
    Retrieves the list of all prompts provided by the server.
    
    Returns:
    
    A Mono that completes with the list of prompts result.
    
    See Also:
    
    McpSchema.ListPromptsResult, #getPrompt(GetPromptRequest)
  - listPrompts
```
public reactor.core.publisher.Mono<McpSchema.ListPromptsResult> listPrompts(String cursor)
```
    Retrieves a paginated list of prompts provided by the server.
    
    Parameters:
    
    cursor - Optional pagination cursor from a previous list request
    
    Returns:
    
    A Mono that completes with the list of prompts result.
    
    See Also:
    
    McpSchema.ListPromptsResult, #getPrompt(GetPromptRequest)
  - getPrompt
```
public reactor.core.publisher.Mono<McpSchema.GetPromptResult> getPrompt(McpSchema.GetPromptRequest getPromptRequest)
```
    Retrieves a specific prompt by its ID. This provides the complete prompt template including all parameters and instructions for generating AI content.
    
    Parameters:
    
    getPromptRequest - The request containing the ID of the prompt to retrieve.
    
    Returns:
    
    A Mono that completes with the prompt result.
    
    See Also:
    
    McpSchema.GetPromptRequest, McpSchema.GetPromptResult, listPrompts()
  - setLoggingLevel
```
public reactor.core.publisher.Mono<Void> setLoggingLevel(McpSchema.LoggingLevel loggingLevel)
```
    Sets the minimum logging level for messages received from the server. The client will only receive log messages at or above the specified severity level.
    
    Parameters:
    
    loggingLevel - The minimum logging level to receive.
    
    Returns:
    
    A Mono that completes when the logging level is set.
    
    See Also:
    
    McpSchema.LoggingLevel

Class McpAsyncClient

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

initializedSink

Method Detail

getServerCapabilities

getServerInfo

isInitialized

getClientCapabilities

getClientInfo

close

closeGracefully

initialize

ping

addRoot

removeRoot

rootsListChangedNotification

callTool

listTools

listTools

listResources

listResources

readResource

readResource

listResourceTemplates

listResourceTemplates

subscribeResource

unsubscribeResource

listPrompts

listPrompts

getPrompt

setLoggingLevel