Class McpServer

constructor

• new McpServer(
      serverInfo: {
          icons?: {
              mimeType?: string;
              sizes?: string[];
              src: string;
              [key: string]: unknown;
          }[];
          name: string;
          title?: string;
          version: string;
          websiteUrl?: string;
          [key: string]: unknown;
      },
      options?: ServerOptions,
  ): McpServer

  Parameters

  • serverInfo: {
        icons?: {
            mimeType?: string;
            sizes?: string[];
            src: string;
            [key: string]: unknown;
        }[];
        name: string;
        title?: string;
        version: string;
        websiteUrl?: string;
        [key: string]: unknown;
    }

    • [key: string]: unknown

    • Optionalicons?: { mimeType?: string; sizes?: string[]; src: string; [key: string]: unknown }[]

      Optional set of sized icons that the client can display in a user interface.

      Clients that support rendering icons MUST support at least the following MIME types:

      • image/png - PNG images (safe, universal compatibility)
      • image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

      Clients that support rendering icons SHOULD also support:

      • image/svg+xml - SVG images (scalable but requires security precautions)
      • image/webp - WebP images (modern, efficient format)

    • name: string

      Intended for programmatic or logical use, but used as a display name in past specs or fallback

    • Optionaltitle?: string

      Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

      If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

    • version: string

    • OptionalwebsiteUrl?: string

      An optional URL of the website for this implementation.

  • Optionaloptions: ServerOptions

  Returns McpServer

Readonlyserver

close

• close(): Promise<void>

  Closes the connection.

  Returns Promise<void>

connect

• connect(transport: Transport): Promise<void>

  Attaches to the given transport, starts it, and starts listening for messages.

  The server object assumes ownership of the Transport, replacing any callbacks that have already been set, and expects that it is the only user of the Transport instance going forward.

  Parameters

  • transport: Transport

  Returns Promise<void>

isConnected

• isConnected(): boolean

  Checks if the server is connected to a transport.

  Returns boolean

  True if the server is connected

prompt

• prompt(
      name: string,
      cb: (
          extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
      ) =>
          | {
              _meta?: { [key: string]: unknown };
              description?: string;
              messages: {
                  content:
                      | {
                          _meta?: { [key: string]: unknown };
                          text: string;
                          type: "text";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "image";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "audio";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          resource:
                              | {
                                  _meta?: { [key: ...]: ... };
                                  mimeType?: string;
                                  text: string;
                                  uri: string;
                                  [key: string]: unknown;
                              }
                              | {
                                  _meta?: { [key: ...]: ... };
                                  blob: string;
                                  mimeType?: string;
                                  uri: string;
                                  [key: string]: unknown;
                              };
                          type: "resource";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          description?: string;
                          icons?: {
                              mimeType?: (...) | (...);
                              sizes?: (...) | (...);
                              src: string;
                              [key: string]: unknown;
                          }[];
                          mimeType?: string;
                          name: string;
                          title?: string;
                          type: "resource_link";
                          uri: string;
                          [key: string]: unknown;
                      };
                  role: "user"
                  | "assistant";
                  [key: string]: unknown;
              }[];
              [key: string]: unknown;
          }
          | Promise<
              {
                  _meta?: { [key: string]: unknown };
                  description?: string;
                  messages: {
                      content:
                          | {
                              _meta?: { [key: string]: unknown };
                              text: string;
                              type: "text";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              data: string;
                              mimeType: string;
                              type: "image";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              data: string;
                              mimeType: string;
                              type: "audio";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              resource:
                                  | {
                                      _meta?: (...)
                                      | (...);
                                      mimeType?: (...) | (...);
                                      text: string;
                                      uri: string;
                                      [key: string]: unknown;
                                  }
                                  | {
                                      _meta?: (...)
                                      | (...);
                                      blob: string;
                                      mimeType?: (...) | (...);
                                      uri: string;
                                      [key: string]: unknown;
                                  };
                              type: "resource";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              description?: string;
                              icons?: { mimeType?: ...; sizes?: ...; src: ...; [key: ...]: ... }[];
                              mimeType?: string;
                              name: string;
                              title?: string;
                              type: "resource_link";
                              uri: string;
                              [key: string]: unknown;
                          };
                      role: "user"
                      | "assistant";
                      [key: string]: unknown;
                  }[];
                  [key: string]: unknown;
              },
          >,
  ): RegisteredPrompt

  Registers a zero-argument prompt name, which will run the given function when the client calls it.

  Parameters

  • name: string
  • cb: (
        extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
    ) =>
        | {
            _meta?: { [key: string]: unknown };
            description?: string;
            messages: {
                content:
                    | {
                        _meta?: { [key: string]: unknown };
                        text: string;
                        type: "text";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "image";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "audio";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        resource:
                            | {
                                _meta?: { [key: ...]: ... };
                                mimeType?: string;
                                text: string;
                                uri: string;
                                [key: string]: unknown;
                            }
                            | {
                                _meta?: { [key: ...]: ... };
                                blob: string;
                                mimeType?: string;
                                uri: string;
                                [key: string]: unknown;
                            };
                        type: "resource";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        description?: string;
                        icons?: {
                            mimeType?: (...) | (...);
                            sizes?: (...) | (...);
                            src: string;
                            [key: string]: unknown;
                        }[];
                        mimeType?: string;
                        name: string;
                        title?: string;
                        type: "resource_link";
                        uri: string;
                        [key: string]: unknown;
                    };
                role: "user"
                | "assistant";
                [key: string]: unknown;
            }[];
            [key: string]: unknown;
        }
        | Promise<
            {
                _meta?: { [key: string]: unknown };
                description?: string;
                messages: {
                    content:
                        | {
                            _meta?: { [key: string]: unknown };
                            text: string;
                            type: "text";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            data: string;
                            mimeType: string;
                            type: "image";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            data: string;
                            mimeType: string;
                            type: "audio";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            resource:
                                | {
                                    _meta?: (...)
                                    | (...);
                                    mimeType?: (...) | (...);
                                    text: string;
                                    uri: string;
                                    [key: string]: unknown;
                                }
                                | {
                                    _meta?: (...)
                                    | (...);
                                    blob: string;
                                    mimeType?: (...) | (...);
                                    uri: string;
                                    [key: string]: unknown;
                                };
                            type: "resource";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            description?: string;
                            icons?: { mimeType?: ...; sizes?: ...; src: ...; [key: ...]: ... }[];
                            mimeType?: string;
                            name: string;
                            title?: string;
                            type: "resource_link";
                            uri: string;
                            [key: string]: unknown;
                        };
                    role: "user"
                    | "assistant";
                    [key: string]: unknown;
                }[];
                [key: string]: unknown;
            },
        >

  Returns RegisteredPrompt

  Deprecated

  Use registerPrompt instead.

• prompt(
      name: string,
      description: string,
      cb: (
          extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
      ) =>
          | {
              _meta?: { [key: string]: unknown };
              description?: string;
              messages: {
                  content:
                      | {
                          _meta?: { [key: string]: unknown };
                          text: string;
                          type: "text";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "image";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "audio";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          resource:
                              | {
                                  _meta?: { [key: ...]: ... };
                                  mimeType?: string;
                                  text: string;
                                  uri: string;
                                  [key: string]: unknown;
                              }
                              | {
                                  _meta?: { [key: ...]: ... };
                                  blob: string;
                                  mimeType?: string;
                                  uri: string;
                                  [key: string]: unknown;
                              };
                          type: "resource";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          description?: string;
                          icons?: {
                              mimeType?: (...) | (...);
                              sizes?: (...) | (...);
                              src: string;
                              [key: string]: unknown;
                          }[];
                          mimeType?: string;
                          name: string;
                          title?: string;
                          type: "resource_link";
                          uri: string;
                          [key: string]: unknown;
                      };
                  role: "user"
                  | "assistant";
                  [key: string]: unknown;
              }[];
              [key: string]: unknown;
          }
          | Promise<
              {
                  _meta?: { [key: string]: unknown };
                  description?: string;
                  messages: {
                      content:
                          | {
                              _meta?: { [key: string]: unknown };
                              text: string;
                              type: "text";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              data: string;
                              mimeType: string;
                              type: "image";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              data: string;
                              mimeType: string;
                              type: "audio";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              resource:
                                  | {
                                      _meta?: (...)
                                      | (...);
                                      mimeType?: (...) | (...);
                                      text: string;
                                      uri: string;
                                      [key: string]: unknown;
                                  }
                                  | {
                                      _meta?: (...)
                                      | (...);
                                      blob: string;
                                      mimeType?: (...) | (...);
                                      uri: string;
                                      [key: string]: unknown;
                                  };
                              type: "resource";
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              description?: string;
                              icons?: { mimeType?: ...; sizes?: ...; src: ...; [key: ...]: ... }[];
                              mimeType?: string;
                              name: string;
                              title?: string;
                              type: "resource_link";
                              uri: string;
                              [key: string]: unknown;
                          };
                      role: "user"
                      | "assistant";
                      [key: string]: unknown;
                  }[];
                  [key: string]: unknown;
              },
          >,
  ): RegisteredPrompt

  Registers a zero-argument prompt name (with a description) which will run the given function when the client calls it.

  Parameters

  • name: string
  • description: string
  • cb: (
        extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
    ) =>
        | {
            _meta?: { [key: string]: unknown };
            description?: string;
            messages: {
                content:
                    | {
                        _meta?: { [key: string]: unknown };
                        text: string;
                        type: "text";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "image";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "audio";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        resource:
                            | {
                                _meta?: { [key: ...]: ... };
                                mimeType?: string;
                                text: string;
                                uri: string;
                                [key: string]: unknown;
                            }
                            | {
                                _meta?: { [key: ...]: ... };
                                blob: string;
                                mimeType?: string;
                                uri: string;
                                [key: string]: unknown;
                            };
                        type: "resource";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        description?: string;
                        icons?: {
                            mimeType?: (...) | (...);
                            sizes?: (...) | (...);
                            src: string;
                            [key: string]: unknown;
                        }[];
                        mimeType?: string;
                        name: string;
                        title?: string;
                        type: "resource_link";
                        uri: string;
                        [key: string]: unknown;
                    };
                role: "user"
                | "assistant";
                [key: string]: unknown;
            }[];
            [key: string]: unknown;
        }
        | Promise<
            {
                _meta?: { [key: string]: unknown };
                description?: string;
                messages: {
                    content:
                        | {
                            _meta?: { [key: string]: unknown };
                            text: string;
                            type: "text";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            data: string;
                            mimeType: string;
                            type: "image";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            data: string;
                            mimeType: string;
                            type: "audio";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            resource:
                                | {
                                    _meta?: (...)
                                    | (...);
                                    mimeType?: (...) | (...);
                                    text: string;
                                    uri: string;
                                    [key: string]: unknown;
                                }
                                | {
                                    _meta?: (...)
                                    | (...);
                                    blob: string;
                                    mimeType?: (...) | (...);
                                    uri: string;
                                    [key: string]: unknown;
                                };
                            type: "resource";
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            description?: string;
                            icons?: { mimeType?: ...; sizes?: ...; src: ...; [key: ...]: ... }[];
                            mimeType?: string;
                            name: string;
                            title?: string;
                            type: "resource_link";
                            uri: string;
                            [key: string]: unknown;
                        };
                    role: "user"
                    | "assistant";
                    [key: string]: unknown;
                }[];
                [key: string]: unknown;
            },
        >

  Returns RegisteredPrompt

  Deprecated

  Use registerPrompt instead.

• prompt<Args extends PromptArgsRawShape>(
      name: string,
      argsSchema: Args,
      cb: PromptCallback<Args>,
  ): RegisteredPrompt

  Registers a prompt name accepting the given arguments, which must be an object containing named properties associated with Zod schemas. When the client calls it, the function will be run with the parsed and validated arguments.

  Type Parameters

  • Args extends PromptArgsRawShape

  Parameters

  • name: string
  • argsSchema: Args
  • cb: PromptCallback<Args>

  Returns RegisteredPrompt

  Deprecated

  Use registerPrompt instead.

• prompt<Args extends PromptArgsRawShape>(
      name: string,
      description: string,
      argsSchema: Args,
      cb: PromptCallback<Args>,
  ): RegisteredPrompt

  Registers a prompt name (with a description) accepting the given arguments, which must be an object containing named properties associated with Zod schemas. When the client calls it, the function will be run with the parsed and validated arguments.

  Type Parameters

  • Args extends PromptArgsRawShape

  Parameters

  • name: string
  • description: string
  • argsSchema: Args
  • cb: PromptCallback<Args>

  Returns RegisteredPrompt

  Deprecated

  Use registerPrompt instead.

registerPrompt

• registerPrompt<Args extends PromptArgsRawShape>(
      name: string,
      config: { argsSchema?: Args; description?: string; title?: string },
      cb: PromptCallback<Args>,
  ): RegisteredPrompt

  Registers a prompt with a config object and callback.

  Type Parameters

  • Args extends PromptArgsRawShape

  Parameters

  • name: string
  • config: { argsSchema?: Args; description?: string; title?: string }
  • cb: PromptCallback<Args>

  Returns RegisteredPrompt

registerResource

• registerResource(
      name: string,
      uriOrTemplate: string,
      config: ResourceMetadata,
      readCallback: ReadResourceCallback,
  ): RegisteredResource

  Registers a resource with a config object and callback. For static resources, use a URI string. For dynamic resources, use a ResourceTemplate.

  Parameters

  • name: string
  • uriOrTemplate: string
  • config: ResourceMetadata
  • readCallback: ReadResourceCallback

  Returns RegisteredResource

• registerResource(
      name: string,
      uriOrTemplate: ResourceTemplate,
      config: ResourceMetadata,
      readCallback: ReadResourceTemplateCallback,
  ): RegisteredResourceTemplate

  Registers a resource with a config object and callback. For static resources, use a URI string. For dynamic resources, use a ResourceTemplate.

  Parameters

  • name: string
  • uriOrTemplate: ResourceTemplate
  • config: ResourceMetadata
  • readCallback: ReadResourceTemplateCallback

  Returns RegisteredResourceTemplate

registerTool

• registerTool<InputArgs extends ZodRawShape, OutputArgs extends ZodRawShape>(
      name: string,
      config: {
          _meta?: Record<string, unknown>;
          annotations?: {
              destructiveHint?: boolean;
              idempotentHint?: boolean;
              openWorldHint?: boolean;
              readOnlyHint?: boolean;
              title?: string;
              [key: string]: unknown;
          };
          description?: string;
          inputSchema?: InputArgs;
          outputSchema?: OutputArgs;
          title?: string;
      },
      cb: ToolCallback<InputArgs>,
  ): RegisteredTool

  Registers a tool with a config object and callback.

  Type Parameters

  • InputArgs extends ZodRawShape
  • OutputArgs extends ZodRawShape

  Parameters

  • name: string
  • config: {
        _meta?: Record<string, unknown>;
        annotations?: {
            destructiveHint?: boolean;
            idempotentHint?: boolean;
            openWorldHint?: boolean;
            readOnlyHint?: boolean;
            title?: string;
            [key: string]: unknown;
        };
        description?: string;
        inputSchema?: InputArgs;
        outputSchema?: OutputArgs;
        title?: string;
    }
  • cb: ToolCallback<InputArgs>

  Returns RegisteredTool

resource

• resource(
      name: string,
      uri: string,
      readCallback: ReadResourceCallback,
  ): RegisteredResource

  Registers a resource name at a fixed URI, which will use the given callback to respond to read requests.

  Parameters

  • name: string
  • uri: string
  • readCallback: ReadResourceCallback

  Returns RegisteredResource

  Deprecated

  Use registerResource instead.

• resource(
      name: string,
      uri: string,
      metadata: ResourceMetadata,
      readCallback: ReadResourceCallback,
  ): RegisteredResource

  Registers a resource name at a fixed URI with metadata, which will use the given callback to respond to read requests.

  Parameters

  • name: string
  • uri: string
  • metadata: ResourceMetadata
  • readCallback: ReadResourceCallback

  Returns RegisteredResource

  Deprecated

  Use registerResource instead.

• resource(
      name: string,
      template: ResourceTemplate,
      readCallback: ReadResourceTemplateCallback,
  ): RegisteredResourceTemplate

  Registers a resource name with a template pattern, which will use the given callback to respond to read requests.

  Parameters

  • name: string
  • template: ResourceTemplate
  • readCallback: ReadResourceTemplateCallback

  Returns RegisteredResourceTemplate

  Deprecated

  Use registerResource instead.

• resource(
      name: string,
      template: ResourceTemplate,
      metadata: ResourceMetadata,
      readCallback: ReadResourceTemplateCallback,
  ): RegisteredResourceTemplate

  Registers a resource name with a template pattern and metadata, which will use the given callback to respond to read requests.

  Parameters

  • name: string
  • template: ResourceTemplate
  • metadata: ResourceMetadata
  • readCallback: ReadResourceTemplateCallback

  Returns RegisteredResourceTemplate

  Deprecated

  Use registerResource instead.

sendLoggingMessage

• sendLoggingMessage(
      params: {
          _meta?: { [key: string]: unknown };
          data?: unknown;
          level:
              | "error"
              | "debug"
              | "info"
              | "notice"
              | "warning"
              | "critical"
              | "alert"
              | "emergency";
          logger?: string;
          [key: string]: unknown;
      },
      sessionId?: string,
  ): Promise<void>

  Sends a logging message to the client, if connected. Note: You only need to send the parameters object, not the entire JSON RPC message

  Parameters

  • params: {
        _meta?: { [key: string]: unknown };
        data?: unknown;
        level:
            | "error"
            | "debug"
            | "info"
            | "notice"
            | "warning"
            | "critical"
            | "alert"
            | "emergency";
        logger?: string;
        [key: string]: unknown;
    }

    • [key: string]: unknown

    • Optional_meta?: { [key: string]: unknown }

      See MCP specification for notes on _meta usage.

    • Optionaldata?: unknown

      The data to be logged, such as a string message or an object. Any JSON serializable type is allowed here.

    • level:
          | "error"
          | "debug"
          | "info"
          | "notice"
          | "warning"
          | "critical"
          | "alert"
          | "emergency"

      The severity of this log message.

    • Optionallogger?: string

      An optional name of the logger issuing this message.

  • OptionalsessionId: string

    optional for stateless and backward compatibility

  Returns Promise<void>

  See

  LoggingMessageNotification

sendPromptListChanged

• sendPromptListChanged(): void

  Sends a prompt list changed event to the client, if connected.

  Returns void

sendResourceListChanged

• sendResourceListChanged(): void

  Sends a resource list changed event to the client, if connected.

  Returns void

sendToolListChanged

• sendToolListChanged(): void

  Sends a tool list changed event to the client, if connected.

  Returns void

tool

• tool(
      name: string,
      cb: (
          extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
      ) =>
          | {
              _meta?: { [key: string]: unknown };
              content: (
                  | {
                      _meta?: { [key: string]: unknown };
                      text: string;
                      type: "text";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      data: string;
                      mimeType: string;
                      type: "image";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      data: string;
                      mimeType: string;
                      type: "audio";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      resource:
                          | {
                              _meta?: { [key: string]: unknown };
                              mimeType?: string;
                              text: string;
                              uri: string;
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              blob: string;
                              mimeType?: string;
                              uri: string;
                              [key: string]: unknown;
                          };
                      type: "resource";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      description?: string;
                      icons?: {
                          mimeType?: string;
                          sizes?: (...)[];
                          src: string;
                          [key: string]: unknown;
                      }[];
                      mimeType?: string;
                      name: string;
                      title?: string;
                      type: "resource_link";
                      uri: string;
                      [key: string]: unknown;
                  }
              )[];
              isError?: boolean;
              structuredContent?: { [key: string]: unknown };
              [key: string]: unknown;
          }
          | Promise<
              {
                  _meta?: { [key: string]: unknown };
                  content: (
                      | {
                          _meta?: { [key: string]: unknown };
                          text: string;
                          type: "text";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "image";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "audio";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          resource:
                              | {
                                  _meta?: { [key: ...]: ... };
                                  mimeType?: string;
                                  text: string;
                                  uri: string;
                                  [key: string]: unknown;
                              }
                              | {
                                  _meta?: { [key: ...]: ... };
                                  blob: string;
                                  mimeType?: string;
                                  uri: string;
                                  [key: string]: unknown;
                              };
                          type: "resource";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          description?: string;
                          icons?: {
                              mimeType?: (...) | (...);
                              sizes?: (...) | (...);
                              src: string;
                              [key: string]: unknown;
                          }[];
                          mimeType?: string;
                          name: string;
                          title?: string;
                          type: "resource_link";
                          uri: string;
                          [key: string]: unknown;
                      }
                  )[];
                  isError?: boolean;
                  structuredContent?: { [key: string]: unknown };
                  [key: string]: unknown;
              },
          >,
  ): RegisteredTool

  Registers a zero-argument tool name, which will run the given function when the client calls it.

  Parameters

  • name: string
  • cb: (
        extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
    ) =>
        | {
            _meta?: { [key: string]: unknown };
            content: (
                | {
                    _meta?: { [key: string]: unknown };
                    text: string;
                    type: "text";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    data: string;
                    mimeType: string;
                    type: "image";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    data: string;
                    mimeType: string;
                    type: "audio";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    resource:
                        | {
                            _meta?: { [key: string]: unknown };
                            mimeType?: string;
                            text: string;
                            uri: string;
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            blob: string;
                            mimeType?: string;
                            uri: string;
                            [key: string]: unknown;
                        };
                    type: "resource";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    description?: string;
                    icons?: {
                        mimeType?: string;
                        sizes?: (...)[];
                        src: string;
                        [key: string]: unknown;
                    }[];
                    mimeType?: string;
                    name: string;
                    title?: string;
                    type: "resource_link";
                    uri: string;
                    [key: string]: unknown;
                }
            )[];
            isError?: boolean;
            structuredContent?: { [key: string]: unknown };
            [key: string]: unknown;
        }
        | Promise<
            {
                _meta?: { [key: string]: unknown };
                content: (
                    | {
                        _meta?: { [key: string]: unknown };
                        text: string;
                        type: "text";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "image";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "audio";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        resource:
                            | {
                                _meta?: { [key: ...]: ... };
                                mimeType?: string;
                                text: string;
                                uri: string;
                                [key: string]: unknown;
                            }
                            | {
                                _meta?: { [key: ...]: ... };
                                blob: string;
                                mimeType?: string;
                                uri: string;
                                [key: string]: unknown;
                            };
                        type: "resource";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        description?: string;
                        icons?: {
                            mimeType?: (...) | (...);
                            sizes?: (...) | (...);
                            src: string;
                            [key: string]: unknown;
                        }[];
                        mimeType?: string;
                        name: string;
                        title?: string;
                        type: "resource_link";
                        uri: string;
                        [key: string]: unknown;
                    }
                )[];
                isError?: boolean;
                structuredContent?: { [key: string]: unknown };
                [key: string]: unknown;
            },
        >

  Returns RegisteredTool

  Deprecated

  Use registerTool instead.

• tool(
      name: string,
      description: string,
      cb: (
          extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
      ) =>
          | {
              _meta?: { [key: string]: unknown };
              content: (
                  | {
                      _meta?: { [key: string]: unknown };
                      text: string;
                      type: "text";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      data: string;
                      mimeType: string;
                      type: "image";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      data: string;
                      mimeType: string;
                      type: "audio";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      resource:
                          | {
                              _meta?: { [key: string]: unknown };
                              mimeType?: string;
                              text: string;
                              uri: string;
                              [key: string]: unknown;
                          }
                          | {
                              _meta?: { [key: string]: unknown };
                              blob: string;
                              mimeType?: string;
                              uri: string;
                              [key: string]: unknown;
                          };
                      type: "resource";
                      [key: string]: unknown;
                  }
                  | {
                      _meta?: { [key: string]: unknown };
                      description?: string;
                      icons?: {
                          mimeType?: string;
                          sizes?: (...)[];
                          src: string;
                          [key: string]: unknown;
                      }[];
                      mimeType?: string;
                      name: string;
                      title?: string;
                      type: "resource_link";
                      uri: string;
                      [key: string]: unknown;
                  }
              )[];
              isError?: boolean;
              structuredContent?: { [key: string]: unknown };
              [key: string]: unknown;
          }
          | Promise<
              {
                  _meta?: { [key: string]: unknown };
                  content: (
                      | {
                          _meta?: { [key: string]: unknown };
                          text: string;
                          type: "text";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "image";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          data: string;
                          mimeType: string;
                          type: "audio";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          resource:
                              | {
                                  _meta?: { [key: ...]: ... };
                                  mimeType?: string;
                                  text: string;
                                  uri: string;
                                  [key: string]: unknown;
                              }
                              | {
                                  _meta?: { [key: ...]: ... };
                                  blob: string;
                                  mimeType?: string;
                                  uri: string;
                                  [key: string]: unknown;
                              };
                          type: "resource";
                          [key: string]: unknown;
                      }
                      | {
                          _meta?: { [key: string]: unknown };
                          description?: string;
                          icons?: {
                              mimeType?: (...) | (...);
                              sizes?: (...) | (...);
                              src: string;
                              [key: string]: unknown;
                          }[];
                          mimeType?: string;
                          name: string;
                          title?: string;
                          type: "resource_link";
                          uri: string;
                          [key: string]: unknown;
                      }
                  )[];
                  isError?: boolean;
                  structuredContent?: { [key: string]: unknown };
                  [key: string]: unknown;
              },
          >,
  ): RegisteredTool

  Registers a zero-argument tool name (with a description) which will run the given function when the client calls it.

  Parameters

  • name: string
  • description: string
  • cb: (
        extra: RequestHandlerExtra<ServerRequest, ServerNotification>,
    ) =>
        | {
            _meta?: { [key: string]: unknown };
            content: (
                | {
                    _meta?: { [key: string]: unknown };
                    text: string;
                    type: "text";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    data: string;
                    mimeType: string;
                    type: "image";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    data: string;
                    mimeType: string;
                    type: "audio";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    resource:
                        | {
                            _meta?: { [key: string]: unknown };
                            mimeType?: string;
                            text: string;
                            uri: string;
                            [key: string]: unknown;
                        }
                        | {
                            _meta?: { [key: string]: unknown };
                            blob: string;
                            mimeType?: string;
                            uri: string;
                            [key: string]: unknown;
                        };
                    type: "resource";
                    [key: string]: unknown;
                }
                | {
                    _meta?: { [key: string]: unknown };
                    description?: string;
                    icons?: {
                        mimeType?: string;
                        sizes?: (...)[];
                        src: string;
                        [key: string]: unknown;
                    }[];
                    mimeType?: string;
                    name: string;
                    title?: string;
                    type: "resource_link";
                    uri: string;
                    [key: string]: unknown;
                }
            )[];
            isError?: boolean;
            structuredContent?: { [key: string]: unknown };
            [key: string]: unknown;
        }
        | Promise<
            {
                _meta?: { [key: string]: unknown };
                content: (
                    | {
                        _meta?: { [key: string]: unknown };
                        text: string;
                        type: "text";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "image";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        data: string;
                        mimeType: string;
                        type: "audio";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        resource:
                            | {
                                _meta?: { [key: ...]: ... };
                                mimeType?: string;
                                text: string;
                                uri: string;
                                [key: string]: unknown;
                            }
                            | {
                                _meta?: { [key: ...]: ... };
                                blob: string;
                                mimeType?: string;
                                uri: string;
                                [key: string]: unknown;
                            };
                        type: "resource";
                        [key: string]: unknown;
                    }
                    | {
                        _meta?: { [key: string]: unknown };
                        description?: string;
                        icons?: {
                            mimeType?: (...) | (...);
                            sizes?: (...) | (...);
                            src: string;
                            [key: string]: unknown;
                        }[];
                        mimeType?: string;
                        name: string;
                        title?: string;
                        type: "resource_link";
                        uri: string;
                        [key: string]: unknown;
                    }
                )[];
                isError?: boolean;
                structuredContent?: { [key: string]: unknown };
                [key: string]: unknown;
            },
        >

  Returns RegisteredTool

  Deprecated

  Use registerTool instead.

• tool<Args extends ZodRawShape>(
      name: string,
      paramsSchemaOrAnnotations:
          | {
              destructiveHint?: boolean;
              idempotentHint?: boolean;
              openWorldHint?: boolean;
              readOnlyHint?: boolean;
              title?: string;
              [key: string]: unknown;
          }
          | Args,
      cb: ToolCallback<Args>,
  ): RegisteredTool

  Registers a tool taking either a parameter schema for validation or annotations for additional metadata. This unified overload handles both tool(name, paramsSchema, cb) and tool(name, annotations, cb) cases.

  Note: We use a union type for the second parameter because TypeScript cannot reliably disambiguate between ToolAnnotations and ZodRawShape during overload resolution, as both are plain object types.

  Type Parameters

  • Args extends ZodRawShape

  Parameters

  • name: string
  • paramsSchemaOrAnnotations:
        | {
            destructiveHint?: boolean;
            idempotentHint?: boolean;
            openWorldHint?: boolean;
            readOnlyHint?: boolean;
            title?: string;
            [key: string]: unknown;
        }
        | Args
    • {
          destructiveHint?: boolean;
          idempotentHint?: boolean;
          openWorldHint?: boolean;
          readOnlyHint?: boolean;
          title?: string;
          [key: string]: unknown;
      }

      • [key: string]: unknown

      • OptionaldestructiveHint?: boolean

        If true, the tool may perform destructive updates to its environment. If false, the tool performs only additive updates.

        (This property is meaningful only when readOnlyHint == false)

        Default: true

      • OptionalidempotentHint?: boolean

        If true, calling the tool repeatedly with the same arguments will have no additional effect on the its environment.

        (This property is meaningful only when readOnlyHint == false)

        Default: false

      • OptionalopenWorldHint?: boolean

        If true, this tool may interact with an "open world" of external entities. If false, the tool's domain of interaction is closed. For example, the world of a web search tool is open, whereas that of a memory tool is not.

        Default: true

      • OptionalreadOnlyHint?: boolean

        If true, the tool does not modify its environment.

        Default: false

      • Optionaltitle?: string

        A human-readable title for the tool.

    • Args
  • cb: ToolCallback<Args>

  Returns RegisteredTool

  Deprecated

  Use registerTool instead.

• tool<Args extends ZodRawShape>(
      name: string,
      description: string,
      paramsSchemaOrAnnotations:
          | {
              destructiveHint?: boolean;
              idempotentHint?: boolean;
              openWorldHint?: boolean;
              readOnlyHint?: boolean;
              title?: string;
              [key: string]: unknown;
          }
          | Args,
      cb: ToolCallback<Args>,
  ): RegisteredTool

  Registers a tool name (with a description) taking either parameter schema or annotations. This unified overload handles both tool(name, description, paramsSchema, cb) and tool(name, description, annotations, cb) cases.

  Note: We use a union type for the third parameter because TypeScript cannot reliably disambiguate between ToolAnnotations and ZodRawShape during overload resolution, as both are plain object types.

  Type Parameters

  • Args extends ZodRawShape

  Parameters

  • name: string
  • description: string
  • paramsSchemaOrAnnotations:
        | {
            destructiveHint?: boolean;
            idempotentHint?: boolean;
            openWorldHint?: boolean;
            readOnlyHint?: boolean;
            title?: string;
            [key: string]: unknown;
        }
        | Args
    • {
          destructiveHint?: boolean;
          idempotentHint?: boolean;
          openWorldHint?: boolean;
          readOnlyHint?: boolean;
          title?: string;
          [key: string]: unknown;
      }

      • [key: string]: unknown

      • OptionaldestructiveHint?: boolean

        If true, the tool may perform destructive updates to its environment. If false, the tool performs only additive updates.

        (This property is meaningful only when readOnlyHint == false)

        Default: true

      • OptionalidempotentHint?: boolean

        If true, calling the tool repeatedly with the same arguments will have no additional effect on the its environment.

        (This property is meaningful only when readOnlyHint == false)

        Default: false

      • OptionalopenWorldHint?: boolean

        If true, this tool may interact with an "open world" of external entities. If false, the tool's domain of interaction is closed. For example, the world of a web search tool is open, whereas that of a memory tool is not.

        Default: true

      • OptionalreadOnlyHint?: boolean

        If true, the tool does not modify its environment.

        Default: false

      • Optionaltitle?: string

        A human-readable title for the tool.

    • Args
  • cb: ToolCallback<Args>

  Returns RegisteredTool

  Deprecated

  Use registerTool instead.

• tool<Args extends ZodRawShape>(
      name: string,
      paramsSchema: Args,
      annotations: {
          destructiveHint?: boolean;
          idempotentHint?: boolean;
          openWorldHint?: boolean;
          readOnlyHint?: boolean;
          title?: string;
          [key: string]: unknown;
      },
      cb: ToolCallback<Args>,
  ): RegisteredTool

  Registers a tool with both parameter schema and annotations.

  Type Parameters

  • Args extends ZodRawShape

  Parameters

  • name: string
  • paramsSchema: Args
  • annotations: {
        destructiveHint?: boolean;
        idempotentHint?: boolean;
        openWorldHint?: boolean;
        readOnlyHint?: boolean;
        title?: string;
        [key: string]: unknown;
    }

    • [key: string]: unknown

    • OptionaldestructiveHint?: boolean

      If true, the tool may perform destructive updates to its environment. If false, the tool performs only additive updates.

      (This property is meaningful only when readOnlyHint == false)

      Default: true

    • OptionalidempotentHint?: boolean

      If true, calling the tool repeatedly with the same arguments will have no additional effect on the its environment.

      (This property is meaningful only when readOnlyHint == false)

      Default: false

    • OptionalopenWorldHint?: boolean

      If true, this tool may interact with an "open world" of external entities. If false, the tool's domain of interaction is closed. For example, the world of a web search tool is open, whereas that of a memory tool is not.

      Default: true

    • OptionalreadOnlyHint?: boolean

      If true, the tool does not modify its environment.

      Default: false

    • Optionaltitle?: string

      A human-readable title for the tool.

  • cb: ToolCallback<Args>

  Returns RegisteredTool

  Deprecated

  Use registerTool instead.

• tool<Args extends ZodRawShape>(
      name: string,
      description: string,
      paramsSchema: Args,
      annotations: {
          destructiveHint?: boolean;
          idempotentHint?: boolean;
          openWorldHint?: boolean;
          readOnlyHint?: boolean;
          title?: string;
          [key: string]: unknown;
      },
      cb: ToolCallback<Args>,
  ): RegisteredTool

  Registers a tool with description, parameter schema, and annotations.

  Type Parameters

  • Args extends ZodRawShape

  Parameters

  • name: string
  • description: string
  • paramsSchema: Args
  • annotations: {
        destructiveHint?: boolean;
        idempotentHint?: boolean;
        openWorldHint?: boolean;
        readOnlyHint?: boolean;
        title?: string;
        [key: string]: unknown;
    }

    • [key: string]: unknown

    • OptionaldestructiveHint?: boolean

      If true, the tool may perform destructive updates to its environment. If false, the tool performs only additive updates.

      (This property is meaningful only when readOnlyHint == false)

      Default: true

    • OptionalidempotentHint?: boolean

      If true, calling the tool repeatedly with the same arguments will have no additional effect on the its environment.

      (This property is meaningful only when readOnlyHint == false)

      Default: false

    • OptionalopenWorldHint?: boolean

      If true, this tool may interact with an "open world" of external entities. If false, the tool's domain of interaction is closed. For example, the world of a web search tool is open, whereas that of a memory tool is not.

      Default: true

    • OptionalreadOnlyHint?: boolean

      If true, the tool does not modify its environment.

      Default: false

    • Optionaltitle?: string

      A human-readable title for the tool.

  • cb: ToolCallback<Args>

  Returns RegisteredTool

  Deprecated

  Use registerTool instead.