Class InMemoryMcpTaskStore

Namespace

ModelContextProtocol.Server

Assembly

ModelContextProtocol.Core.dll

Provides an in-memory implementation of IMcpTaskStore for development and testing scenarios.

public class InMemoryMcpTaskStore : IMcpTaskStore

Inheritance

object

InMemoryMcpTaskStore

Implements

IMcpTaskStore

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

This implementation stores all task state in memory using immutable snapshots and compare-and-swap updates for thread safety without locks. Tasks are not persisted across process restarts.

For production scenarios requiring durability, session isolation, or TTL-based cleanup, implement a custom IMcpTaskStore.

Properties

DefaultPollIntervalMs

Gets or sets the default poll interval in milliseconds for new tasks.

public long DefaultPollIntervalMs { get; set; }

Property Value

long

The default is 1000 milliseconds.

DefaultTimeToLive

Gets or sets the default time-to-live for new tasks, or null for unlimited.

public TimeSpan? DefaultTimeToLive { get; set; }

Property Value

TimeSpan?

Methods

CreateTaskAsync(CancellationToken)

Creates a new task for tracking an asynchronous execution.

public Task<McpTaskInfo> CreateTaskAsync(CancellationToken cancellationToken = default)

Parameters

cancellationToken CancellationToken

Cancellation token for the operation.

Returns

Task<McpTaskInfo>

A McpTaskInfo with a unique task ID, initial status of Working, and timing metadata (TTL, poll interval).

Remarks

Implementations must generate a unique task ID and set appropriate timestamps. The server infrastructure maps the returned McpTaskInfo to the appropriate protocol response type when communicating with clients.

Per the MCP specification (SEP-2663 §306), the returned task MUST be durably created before this method completes: a subsequent GetTaskAsync(string, CancellationToken) with the returned TaskId MUST resolve, even if it runs on a different process or node. Implementations backed by eventually-consistent storage must therefore wait for the write to be visible (e.g., quorum acknowledgement, write-through, or an equivalent barrier) before returning.

GetTaskAsync(string, CancellationToken)

Retrieves the current state of a task.

public Task<McpTaskInfo?> GetTaskAsync(string taskId, CancellationToken cancellationToken = default)

Parameters

taskId string

The unique identifier of the task to retrieve.

cancellationToken CancellationToken

Cancellation token for the operation.

Returns

Task<McpTaskInfo>

A McpTaskInfo representing the current task state, or null if the task does not exist.

ResolveInputRequestsAsync(string, IDictionary<string, InputResponse>, CancellationToken)

Removes input requests that have been satisfied by the provided responses and raises InputResponseReceived for each resolved entry.

public Task ResolveInputRequestsAsync(string taskId, IDictionary<string, InputResponse> inputResponses, CancellationToken cancellationToken = default)

Parameters

taskId string

The unique identifier of the task.

inputResponses IDictionary<string, InputResponse>

The input responses keyed by the original request identifier. Matched input requests are removed from the task's pending set.

cancellationToken CancellationToken

Cancellation token for the operation.

Returns

Task

Remarks

After removing the satisfied requests, if no pending input requests remain the task transitions back to Working. Otherwise it remains in InputRequired.

Implementations must raise InputResponseReceived for each entry in inputResponses after updating the store state. In distributed deployments, this event enables the originating server to be notified even if a different server instance processes the tasks/update request.

SetCancelledAsync(string, CancellationToken)

Transitions the task to Cancelled.

public Task<bool> SetCancelledAsync(string taskId, CancellationToken cancellationToken = default)

Parameters

taskId string

The unique identifier of the task to cancel.

cancellationToken CancellationToken

Cancellation token for the operation.

Returns

Task<bool>

true if the task was successfully cancelled; false if the task does not exist or was already in a terminal state.

SetCompletedAsync(string, JsonElement, CancellationToken)

Stores the result of a completed execution, transitioning the task to Completed.

public Task SetCompletedAsync(string taskId, JsonElement result, CancellationToken cancellationToken = default)

Parameters

taskId string

The unique identifier of the task.

result JsonElement

The serialized result payload.

cancellationToken CancellationToken

Cancellation token for the operation.

Returns

Task

A task representing the asynchronous operation.

SetFailedAsync(string, JsonElement, CancellationToken)

Marks a task as failed, transitioning it to Failed.

public Task SetFailedAsync(string taskId, JsonElement error, CancellationToken cancellationToken = default)

Parameters

taskId string

The unique identifier of the task.

error JsonElement

The serialized error information.

cancellationToken CancellationToken

Cancellation token for the operation.

Returns

Task

A task representing the asynchronous operation.

SetInputRequestsAsync(string, IDictionary<string, InputRequest>, CancellationToken)

Adds input requests to a task, transitioning it to InputRequired.

public Task SetInputRequestsAsync(string taskId, IDictionary<string, InputRequest> inputRequests, CancellationToken cancellationToken = default)

Parameters

taskId string

The unique identifier of the task.

inputRequests IDictionary<string, InputRequest>

The input requests to add. Keys are arbitrary identifiers for matching requests to responses. Each value is an InputRequest wrapping the server-to-client request payload. New requests are merged with any existing pending requests.

cancellationToken CancellationToken

Cancellation token for the operation.

Returns

Task

A task representing the asynchronous operation.

Events

InputResponseReceived

Occurs when an input response is resolved for a task.

public event Action<InputResponseReceivedEventArgs>? InputResponseReceived

Event Type

Action<InputResponseReceivedEventArgs>

Remarks

Implementations must raise this event for each input response resolved in ResolveInputRequestsAsync(string, IDictionary<string, InputResponse>, CancellationToken). Subscribers use this to complete pending input request waiters (e.g., elicitation or sampling calls that are awaiting a client response).