Namespace ModelContextProtocol.Protocol.Types

Classes

Annotations: Represents annotations that can be attached to content. See the schema for details

Argument: Used for completion requests to provide additional context for the completion options. See the schema for details

BlobResourceContents: Binary contents of a resource. See the schema for details

CallToolRequestParams: Used by the client to invoke a tool provided by the server. See the schema for details

The server's response to a tool call.

Any errors that originate from the tool SHOULD be reported inside the result object, with isError set to true, not as an MCP protocol-level error response. Otherwise, the LLM would not be able to see that an error occurred and self-correct.

However, any errors in finding the tool, an error indicating that the server does not support tool calls, or any other exceptional conditions, should be reported as an MCP error response. See the schema for details

ClientCapabilities: Represents the capabilities that a client may support. See the schema for details

CompleteRequestParams: A request from the client to the server, to ask for completion options. See the schema for details

CompleteResult: The server's response to a completion/complete request See the schema for details

Completion: Represents a completion object in the server's response See the schema for details

Content: Represents the content of a tool response. See the schema for details There are multiple subtypes of content, depending on the "type" field, these are represented as separate classes.

CreateMessageRequestParams

A request from the server to sample an LLM via the client. The client has full discretion over which model to select. The client should also inform the user before beginning sampling, to allow them to inspect the request (human in the loop) and decide whether to approve it.

While these align with the protocol specification, clients have full discretion over model selection and should inform users before sampling. See the schema for details

CreateMessageResult: The client's response to a sampling/create_message request from the server. The client should inform the user before returning the sampled message, to allow them to inspect the response (human in the loop) and decide whether to allow the server to see it. See the schema for details

EmptyResult: An empty result object. See the schema for details

GetPromptRequestParams: Used by the client to get a prompt provided by the server. See the schema for details

GetPromptResult: The server's response to a prompts/get request from the client. See the schema for details

Implementation: Describes the name and version of an MCP implementation. See the schema for details

InitializeRequestParams: Parameters for an initialization request sent to the server. See the schema for details

InitializeResult: Result of the initialization request sent to the server. See the schema for details

ListPromptsRequestParams: Sent from the client to request a list of prompts and prompt templates the server has. See the schema for details

ListPromptsResult: The server's response to a prompts/list request from the client. See the schema for details

ListResourceTemplatesRequestParams: Sent from the client to request a list of resource templates the server has. See the schema for details

ListResourceTemplatesResult: The server's response to a resources/templates/list request from the client. See the schema for details

ListResourcesRequestParams: Sent from the client to request a list of resources the server has. See the schema for details

ListResourcesResult: The server's response to a resources/list request from the client. See the schema for details

ListRootsRequestParams: A request from the server to get a list of root URIs from the client. See the schema for details

ListRootsResult: The client's response to a roots/list request from the server. See the schema for details

ListToolsRequestParams: Sent from the client to request a list of tools the server has. See the schema for details

ListToolsResult: A response to a request to list the tools available on the server. See the schema for details

LoggingCapability: Represents the logging capability configuration. See the schema for details

LoggingMessageNotificationParams

Sent from the server as the payload of "notifications/message" notifications whenever a log message is generated.

If no logging/setLevel request has been sent from the client, the server MAY decide which messages to send automatically. See the schema for details

ModelHint: Hints to use for model selection. Keys not declared here are currently left unspecified by the spec and are up to the client to interpret. See the schema for details

ModelPreferences

The server's preferences for model selection, requested of the client during sampling. Because LLMs can vary along multiple dimensions, choosing the "best" model is rarely straightforward. Different models excel in different areas—some are faster but less capable, others are more capable but more expensive, and so on. This interface allows servers to express their priorities across multiple dimensions to help clients make an appropriate selection for their use case.

These preferences are always advisory. The client MAY ignore them. It is also up to the client to decide how to interpret these preferences and how to balance them against other considerations. See the schema for details

PaginatedRequestParams: Used as a base class for paginated requests. See the schema for details

PingResult: Dummy result for the ping request. See the schema for details

Prompt: A prompt or prompt template that the server offers. See the schema for details

PromptArgument: Describes an argument that a prompt can accept. See the schema for details

PromptMessage

Describes a message returned as part of a prompt.

This is similar to SamplingMessage, but also supports the embedding of resources from the MCP server. See the schema for details

PromptsCapability: Represents the prompts capability configuration. See the schema for details

ReadResourceRequestParams: Sent from the client to the server, to read a specific resource URI. See the schema for details

ReadResourceResult: The server's response to a resources/read request from the client. See the schema for details

Reference: Represents a reference to a resource or prompt. Umbrella type for both ResourceReference and PromptReference from the spec schema. See the schema for details

RequestParams: Base class for all request parameters. See the schema for details

RequestParamsMetadata: Metadata related to the request.

Resource: Represents a known resource that the server is capable of reading. See the schema for details

ResourceContents: Represents the content of a resource. See the schema for details

ResourceTemplate: Represents a known resource template that the server is capable of reading. See the schema for details

ResourceUpdatedNotificationParams: Sent from the server as the payload of "notifications/resources/updated" notifications whenever a subscribed resource changes. See the schema for details

ResourcesCapability: Represents the resources capability configuration. See the schema for details

Root: Represents a root URI and its metadata. See the schema for details

RootsCapability: Represents the roots capability configuration. See the schema for details

SamplingCapability: Represents the sampling capability configuration. See the schema for details

SamplingMessage: Describes a message issued to or received from an LLM API. See the schema for details

ServerCapabilities: Represents the capabilities that a server may support. See the schema for details

SetLevelRequestParams: A request from the client to the server, to enable or adjust logging. See the schema for details

SubscribeRequestParams: Sent from the client to request updated notifications from the server whenever a particular primitive changes. See the schema for details

TextResourceContents: Text contents of a resource. See the schema for details

Tool: Represents a tool that the server is capable of calling. Part of the ListToolsResponse. See the schema for details

ToolAnnotations: Additional properties describing a Tool to clients. NOTE: all properties in ToolAnnotations are hints. They are not guaranteed to provide a faithful description of tool behavior (including descriptive properties like title). Clients should never make tool use decisions based on ToolAnnotations received from untrusted servers. See the schema for details There are multiple subtypes of content, depending on the "type" field, these are represented as separate classes.

ToolsCapability: Represents the tools capability configuration. See the schema for details

UnsubscribeFromResourceRequestParams: Sent from the client to request cancellation of resources/updated notifications from the server. This should follow a previous resources/subscribe request. See the schema for details

UnsubscribeRequestParams: Sent from the client to request not receiving updated notifications from the server whenever a primitive resource changes. See the schema for details

Enums

ContextInclusion: A request to include context from one or more MCP servers (including the caller), to be attached to the prompt. See the schema for details

LoggingLevel: The severity of a log message. These map to syslog message severities, as specified in RFC-5424: https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1

Role: Represents the type of role in the conversation. See the schema for details

Table of Contents

Namespace ModelContextProtocol.Protocol.Types

Classes

Enums