FastMCPSession

@codebolt/mcp

---

Class: FastMCPSession<T>

Defined in: packages/mcp/src/mcpServer.ts:556

Class representing a FastMCP session. Manages communication between the client and server.

Extends

• FastMCPSessionEventEmitter

Type Parameters

Type Parameter	Default type
T extends FastMCPSessionAuth	FastMCPSessionAuth

Constructors

Constructor

new FastMCPSession<T>(options: {
  auth?: T;
  name: string;
  prompts: Prompt<Readonly<{
     complete?: ArgumentValueCompleter;
     description?: string;
     enum?: string[];
     name: string;
     required?: boolean;
   }>[], PromptArgumentsToObject<Readonly<{
     complete?: ArgumentValueCompleter;
     description?: string;
     enum?: string[];
     name: string;
     required?: boolean;
  }>[]>>[];
  resources: Resource[];
  resourcesTemplates: InputResourceTemplate<Readonly<{
     complete?: ArgumentValueCompleter;
     description?: string;
     name: string;
  }>[]>[];
  tools: Tool<T, ZodTypeAny>[];
  version: string;
}): FastMCPSession<T>;

Defined in: packages/mcp/src/mcpServer.ts:572

Creates a new FastMCPSession.

Parameters

Parameter	Type	Description
options	{ auth?: T; name: string; prompts: Prompt<Readonly<{ complete?: ArgumentValueCompleter; description?: string; enum?: string[]; name: string; required?: boolean; }>[], PromptArgumentsToObject<Readonly<{ complete?: ArgumentValueCompleter; description?: string; enum?: string[]; name: string; required?: boolean; }>[]>>[]; resources: Resource[]; resourcesTemplates: InputResourceTemplate<Readonly<{ complete?: ArgumentValueCompleter; description?: string; name: string; }>[]>[]; tools: Tool<T, ZodTypeAny>[]; version: string; }	Configuration options for the session
options.auth?	T	-
options.name	string	-
options.prompts	Prompt<Readonly<{ complete?: ArgumentValueCompleter; description?: string; enum?: string[]; name: string; required?: boolean; }>[], PromptArgumentsToObject<Readonly<{ complete?: ArgumentValueCompleter; description?: string; enum?: string[]; name: string; required?: boolean; }>[]>>[]	-
options.resources	Resource[]	-
options.resourcesTemplates	InputResourceTemplate<Readonly<{ complete?: ArgumentValueCompleter; description?: string; name: string; }>[]>[]	-
options.tools	Tool<T, ZodTypeAny>[]	-
options.version	string	-

Returns

FastMCPSession<T>

Overrides

FastMCPSessionEventEmitter.constructor

Properties

Property	Type	Inherited from	Defined in
_emitterType?	EventEmitter<DefaultEventMap>	FastMCPSessionEventEmitter. _emitterType	node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:5
_emitType?	FastMCPSessionEvents	FastMCPSessionEventEmitter. _emitType	node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:7
_eventsType?	FastMCPSessionEvents	FastMCPSessionEventEmitter. _eventsType	node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:6
[captureRejectionSymbol]?	<K>(error: Error, event: string | symbol, ...args: AnyRest) => void	FastMCPSessionEventEmitter.[captureRejectionSymbol]	node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:103

Accessors

clientCapabilities

Get Signature

get clientCapabilities(): 
  | {
[key: string]: unknown;
  elicitation?: {
   [key: string]: unknown;
  };
  experimental?: {
   [key: string]: unknown;
  };
  roots?: {
   [key: string]: unknown;
     listChanged?: boolean;
  };
  sampling?: {
   [key: string]: unknown;
  };
}
  | null;

Defined in: packages/mcp/src/mcpServer.ts:718

Returns

{
[key: string]: unknown;
  elicitation?: {
   [key: string]: unknown;
  };
  experimental?: {
   [key: string]: unknown;
  };
  roots?: {
   [key: string]: unknown;
     listChanged?: boolean;
  };
  sampling?: {
   [key: string]: unknown;
  };
}

Index Signature

[key: string]: unknown

Name	Type	Description	Defined in
elicitation?	{ [key: string]: unknown; }	Present if the client supports eliciting user input.	node_modules/.pnpm/@modelcontextprotocol+sdk@1.19.1/node_modules/@modelcontextprotocol/sdk/dist/esm/types.d.ts:1353
experimental?	{ [key: string]: unknown; }	Experimental, non-standard capabilities that the client supports.	node_modules/.pnpm/@modelcontextprotocol+sdk@1.19.1/node_modules/@modelcontextprotocol/sdk/dist/esm/types.d.ts:1345
roots?	{ [key: string]: unknown; listChanged?: boolean; }	Present if the client supports listing roots.	node_modules/.pnpm/@modelcontextprotocol+sdk@1.19.1/node_modules/@modelcontextprotocol/sdk/dist/esm/types.d.ts:1357
roots.listChanged?	boolean	Whether the client supports issuing notifications for changes to the roots list.	node_modules/.pnpm/@modelcontextprotocol+sdk@1.19.1/node_modules/@modelcontextprotocol/sdk/dist/esm/types.d.ts:1366
sampling?	{ [key: string]: unknown; }	Present if the client supports sampling from an LLM.	node_modules/.pnpm/@modelcontextprotocol+sdk@1.19.1/node_modules/@modelcontextprotocol/sdk/dist/esm/types.d.ts:1349

null

---

loggingLevel

Get Signature

get loggingLevel(): LoggingLevel;

Defined in: packages/mcp/src/mcpServer.ts:799

Returns

LoggingLevel

---

roots

Get Signature

get roots(): {
[key: string]: unknown;
  _meta?: {
   [key: string]: unknown;
  };
  name?: string;
  uri: string;
}[];

Defined in: packages/mcp/src/mcpServer.ts:777

Returns

---

server

Get Signature

get server(): Server;

Defined in: packages/mcp/src/mcpServer.ts:722

Returns

Server

Methods

addListener()

Call Signature

addListener<P, T>(
   this: T, 
   event: P, 
   listener: (...args: ListenerType<FastMCPSessionEvents[P]>) => void): T;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:17

Type Parameters

Type Parameter
P extends keyof FastMCPSessionEvents
T

Parameters

Parameter	Type
this	T
event	P
listener	(...args: ListenerType<FastMCPSessionEvents[P]>) => void

Returns

T

Inherited from

FastMCPSessionEventEmitter.addListener

Call Signature

addListener(event: typeof assignmentCompatibilityHack, listener: (...args: any[]) => any): void;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:18

Parameters

Parameter	Type
event	typeof assignmentCompatibilityHack
listener	(...args: any[]) => any

Returns

void

Inherited from

FastMCPSessionEventEmitter.addListener

---

close()

close(): Promise<void>;

Defined in: packages/mcp/src/mcpServer.ts:781

Returns

Promise<void>

---

connect()

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

Defined in: packages/mcp/src/mcpServer.ts:734

Parameters

Parameter	Type
transport	Transport

Returns

Promise<void>

---

emit()

Call Signature

emit<P, T>(
   this: T, 
   event: P, ...
   args: ListenerType<FastMCPSessionEvents[P]>): T;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:27

Type Parameters

Type Parameter
P extends keyof FastMCPSessionEvents
T

Parameters

Parameter	Type
this	T
event	P
...args	ListenerType<FastMCPSessionEvents[P]>

Returns

T

Inherited from

FastMCPSessionEventEmitter.emit

Call Signature

emit(event: typeof assignmentCompatibilityHack, ...args: any[]): void;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:28

Parameters

Parameter	Type
event	typeof assignmentCompatibilityHack
...args	any[]

Returns

void

Inherited from

FastMCPSessionEventEmitter.emit

---

eventNames()

eventNames(): (string | symbol)[];

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:968

Returns an array listing the events for which the emitter has registered listeners. The values in the array are strings or Symbols.

import { EventEmitter } from 'node:events';

const myEE = new EventEmitter();
myEE.on('foo', () => {});
myEE.on('bar', () => {});

const sym = Symbol('symbol');
myEE.on(sym, () => {});

console.log(myEE.eventNames());
// Prints: [ 'foo', 'bar', Symbol(symbol) ]

Returns

(string | symbol)[]

Since

v6.0.0

Inherited from

FastMCPSessionEventEmitter.eventNames

---

getMaxListeners()

getMaxListeners(): number;

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:820

Returns the current max listener value for the EventEmitter which is either set by emitter.setMaxListeners(n) or defaults to EventEmitter.defaultMaxListeners.

Returns

number

Since

v1.0.0

Inherited from

FastMCPSessionEventEmitter.getMaxListeners

---

listenerCount()

listenerCount<K>(eventName: string | symbol, listener?: Function): number;

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:914

Returns the number of listeners listening for the event named eventName. If listener is provided, it will return how many times the listener is found in the list of the listeners of the event.

Type Parameters

Type Parameter
K

Parameters

Parameter	Type	Description
eventName	string | symbol	The name of the event being listened for
listener?	Function	The event handler function

Returns

number

Since

v3.2.0

Inherited from

FastMCPSessionEventEmitter.listenerCount

---

listeners()

listeners<K>(eventName: string | symbol): Function[];

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:833

Returns a copy of the array of listeners for the event named eventName.

server.on('connection', (stream) => {
  console.log('someone connected!');
});
console.log(util.inspect(server.listeners('connection')));
// Prints: [ [Function] ]

Type Parameters

Type Parameter
K

Parameters

Parameter	Type
eventName	string | symbol

Returns

Function[]

Since

v0.1.26

Inherited from

FastMCPSessionEventEmitter.listeners

---

off()

off<K>(eventName: string | symbol, listener: (...args: any[]) => void): this;

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:793

Alias for emitter.removeListener().

Type Parameters

Type Parameter
K

Parameters

Parameter	Type
eventName	string | symbol
listener	(...args: any[]) => void

Returns

this

Since

v10.0.0

Inherited from

FastMCPSessionEventEmitter.off

---

on()

Call Signature

on<P, T>(
   this: T, 
   event: P, 
   listener: (...args: ListenerType<FastMCPSessionEvents[P]>) => void): T;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:15

Type Parameters

Type Parameter
P extends keyof FastMCPSessionEvents
T

Parameters

Parameter	Type
this	T
event	P
listener	(...args: ListenerType<FastMCPSessionEvents[P]>) => void

Returns

T

Inherited from

FastMCPSessionEventEmitter.on

Call Signature

on(event: typeof assignmentCompatibilityHack, listener: (...args: any[]) => any): void;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:16

Parameters

Parameter	Type
event	typeof assignmentCompatibilityHack
listener	(...args: any[]) => any

Returns

void

Inherited from

FastMCPSessionEventEmitter.on

---

once()

Call Signature

once<P, T>(
   this: T, 
   event: P, 
   listener: (...args: ListenerType<FastMCPSessionEvents[P]>) => void): T;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:25

Type Parameters

Type Parameter
P extends keyof FastMCPSessionEvents
T

Parameters

Parameter	Type
this	T
event	P
listener	(...args: ListenerType<FastMCPSessionEvents[P]>) => void

Returns

T

Inherited from

FastMCPSessionEventEmitter.once

Call Signature

once(event: typeof assignmentCompatibilityHack, listener: (...args: any[]) => any): void;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:26

Parameters

Parameter	Type
event	typeof assignmentCompatibilityHack
listener	(...args: any[]) => any

Returns

void

Inherited from

FastMCPSessionEventEmitter.once

---

prependListener()

prependListener<K>(eventName: string | symbol, listener: (...args: any[]) => void): this;

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:932

Adds the listener function to the beginning of the listeners array for the event named eventName. No checks are made to see if the listener has already been added. Multiple calls passing the same combination of eventName and listener will result in the listener being added, and called, multiple times.

server.prependListener('connection', (stream) => {
  console.log('someone connected!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

Type Parameters

Type Parameter
K

Parameters

Parameter	Type	Description
eventName	string | symbol	The name of the event.
listener	(...args: any[]) => void	The callback function

Returns

this

Since

v6.0.0

Inherited from

FastMCPSessionEventEmitter.prependListener

---

prependOnceListener()

prependOnceListener<K>(eventName: string | symbol, listener: (...args: any[]) => void): this;

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:948

Adds a one-timelistener function for the event named eventName to the beginning of the listeners array. The next time eventName is triggered, this listener is removed, and then invoked.

server.prependOnceListener('connection', (stream) => {
  console.log('Ah, we have our first user!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

Type Parameters

Type Parameter
K

Parameters

Parameter	Type	Description
eventName	string | symbol	The name of the event.
listener	(...args: any[]) => void	The callback function

Returns

this

Since

v6.0.0

Inherited from

FastMCPSessionEventEmitter.prependOnceListener

---

rawListeners()

rawListeners<K>(eventName: string | symbol): Function[];

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:864

Returns a copy of the array of listeners for the event named eventName, including any wrappers (such as those created by .once()).

import { EventEmitter } from 'node:events';
const emitter = new EventEmitter();
emitter.once('log', () => console.log('log once'));

// Returns a new Array with a function `onceWrapper` which has a property
// `listener` which contains the original listener bound above
const listeners = emitter.rawListeners('log');
const logFnWrapper = listeners[0];

// Logs "log once" to the console and does not unbind the `once` event
logFnWrapper.listener();

// Logs "log once" to the console and removes the listener
logFnWrapper();

emitter.on('log', () => console.log('log persistently'));
// Will return a new Array with a single function bound by `.on()` above
const newListeners = emitter.rawListeners('log');

// Logs "log persistently" twice
newListeners[0]();
emitter.emit('log');

Type Parameters

Type Parameter
K

Parameters

Parameter	Type
eventName	string | symbol

Returns

Function[]

Since

v9.4.0

Inherited from

FastMCPSessionEventEmitter.rawListeners

---

removeAllListeners()

removeAllListeners(eventName?: string | symbol): this;

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:804

Removes all listeners, or those of the specified eventName.

It is bad practice to remove listeners added elsewhere in the code, particularly when the EventEmitter instance was created by some other component or module (e.g. sockets or file streams).

Returns a reference to the EventEmitter, so that calls can be chained.

Parameters

Parameter	Type
eventName?	string | symbol

Returns

this

Since

v0.1.26

Inherited from

FastMCPSessionEventEmitter.removeAllListeners

---

removeListener()

Call Signature

removeListener<P, T>(
   this: T, 
   event: P, 
   listener: (...args: any[]) => any): T;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:21

Type Parameters

Type Parameter
P extends keyof FastMCPSessionEvents
T

Parameters

Parameter	Type
this	T
event	P
listener	(...args: any[]) => any

Returns

T

Inherited from

FastMCPSessionEventEmitter.removeListener

Call Signature

removeListener(event: typeof assignmentCompatibilityHack, listener: (...args: any[]) => any): void;

Defined in: node_modules/.pnpm/strict-event-emitter-types@2.0.0/node_modules/strict-event-emitter-types/types/src/index.d.ts:22

Parameters

Parameter	Type
event	typeof assignmentCompatibilityHack
listener	(...args: any[]) => any

Returns

void

Inherited from

FastMCPSessionEventEmitter.removeListener

---

requestSampling()

requestSampling(message: {
  _meta?: objectOutputType<{
     progressToken: ZodOptional<ZodUnion<[ZodString, ZodNumber]>>;
  }, ZodTypeAny, "passthrough">;
  includeContext?: "none" | "thisServer" | "allServers";
  maxTokens: number;
  messages: objectOutputType<{
     content: ZodUnion<[ZodObject<{
        _meta: ZodOptional<ZodObject<..., ..., ..., ..., ...>>;
        text: ZodString;
        type: ZodLiteral<"text">;
      }, "passthrough", ZodTypeAny, objectOutputType<{
        _meta: ZodOptional<...>;
        text: ZodString;
        type: ZodLiteral<...>;
      }, ZodTypeAny, "passthrough">, objectInputType<{
        _meta: ZodOptional<...>;
        text: ZodString;
        type: ZodLiteral<...>;
      }, ZodTypeAny, "passthrough">>, ZodObject<{
        _meta: ZodOptional<ZodObject<..., ..., ..., ..., ...>>;
        data: ZodEffects<ZodString, string, string>;
        mimeType: ZodString;
        type: ZodLiteral<"image">;
      }, "passthrough", ZodTypeAny, objectOutputType<{
        _meta: ZodOptional<...>;
        data: ZodEffects<..., ..., ...>;
        mimeType: ZodString;
        type: ZodLiteral<...>;
      }, ZodTypeAny, "passthrough">, objectInputType<{
        _meta: ZodOptional<...>;
        data: ZodEffects<..., ..., ...>;
        mimeType: ZodString;
        type: ZodLiteral<...>;
      }, ZodTypeAny, "passthrough">>, ZodObject<{
        _meta: ZodOptional<ZodObject<..., ..., ..., ..., ...>>;
        data: ZodEffects<ZodString, string, string>;
        mimeType: ZodString;
        type: ZodLiteral<"audio">;
      }, "passthrough", ZodTypeAny, objectOutputType<{
        _meta: ZodOptional<...>;
        data: ZodEffects<..., ..., ...>;
        mimeType: ZodString;
        type: ZodLiteral<...>;
      }, ZodTypeAny, "passthrough">, objectInputType<{
        _meta: ZodOptional<...>;
        data: ZodEffects<..., ..., ...>;
        mimeType: ZodString;
        type: ZodLiteral<...>;
     }, ZodTypeAny, "passthrough">>]>;
     role: ZodEnum<["user", "assistant"]>;
  }, ZodTypeAny, "passthrough">[];
  metadata?: objectOutputType<{
  }, ZodTypeAny, "passthrough">;
  modelPreferences?: objectOutputType<{
     costPriority: ZodOptional<ZodNumber>;
     hints: ZodOptional<ZodArray<ZodObject<{
        name: ZodOptional<ZodString>;
      }, "passthrough", ZodTypeAny, objectOutputType<{
        name: ZodOptional<...>;
      }, ZodTypeAny, "passthrough">, objectInputType<{
        name: ZodOptional<...>;
     }, ZodTypeAny, "passthrough">>, "many">>;
     intelligencePriority: ZodOptional<ZodNumber>;
     speedPriority: ZodOptional<ZodNumber>;
  }, ZodTypeAny, "passthrough">;
  stopSequences?: string[];
  systemPrompt?: string;
  temperature?: number;
} & {
[k: string]: unknown;
}): Promise<SamplingResponse>;

Defined in: packages/mcp/src/mcpServer.ts:728

Parameters

Parameter

Type

message

{ _meta?: objectOutputType<{ progressToken: ZodOptional<ZodUnion<[ZodString, ZodNumber]>>; }, ZodTypeAny, "passthrough">; includeContext?: "none" | "thisServer" | "allServers"; maxTokens: number; messages: objectOutputType<{ content: ZodUnion<[ZodObject<{ _meta: ZodOptional<ZodObject<..., ..., ..., ..., ...>>; text: ZodString; type: ZodLiteral<"text">; }, "passthrough", ZodTypeAny, objectOutputType<{ _meta: ZodOptional<...>; text: ZodString; type: ZodLiteral<...>; }, ZodTypeAny, "passthrough">, objectInputType<{ _meta: ZodOptional<...>; text: ZodString; type: ZodLiteral<...>; }, ZodTypeAny, "passthrough">>, ZodObject<{ _meta: ZodOptional<ZodObject<..., ..., ..., ..., ...>>; data: ZodEffects<ZodString, string, string>; mimeType: ZodString; type: ZodLiteral<"image">; }, "passthrough", ZodTypeAny, objectOutputType<{ _meta: ZodOptional<...>; data: ZodEffects<..., ..., ...>; mimeType: ZodString; type: ZodLiteral<...>; }, ZodTypeAny, "passthrough">, objectInputType<{ _meta: ZodOptional<...>; data: ZodEffects<..., ..., ...>; mimeType: ZodString; type: ZodLiteral<...>; }, ZodTypeAny, "passthrough">>, ZodObject<{ _meta: ZodOptional<ZodObject<..., ..., ..., ..., ...>>; data: ZodEffects<ZodString, string, string>; mimeType: ZodString; type: ZodLiteral<"audio">; }, "passthrough", ZodTypeAny, objectOutputType<{ _meta: ZodOptional<...>; data: ZodEffects<..., ..., ...>; mimeType: ZodString; type: ZodLiteral<...>; }, ZodTypeAny, "passthrough">, objectInputType<{ _meta: ZodOptional<...>; data: ZodEffects<..., ..., ...>; mimeType: ZodString; type: ZodLiteral<...>; }, ZodTypeAny, "passthrough">>]>; role: ZodEnum<["user", "assistant"]>; }, ZodTypeAny, "passthrough">[]; metadata?: objectOutputType<{ }, ZodTypeAny, "passthrough">; modelPreferences?: objectOutputType<{ costPriority: ZodOptional<ZodNumber>; hints: ZodOptional<ZodArray<ZodObject<{ name: ZodOptional<ZodString>; }, "passthrough", ZodTypeAny, objectOutputType<{ name: ZodOptional<...>; }, ZodTypeAny, "passthrough">, objectInputType<{ name: ZodOptional<...>; }, ZodTypeAny, "passthrough">>, "many">>; intelligencePriority: ZodOptional<ZodNumber>; speedPriority: ZodOptional<ZodNumber>; }, ZodTypeAny, "passthrough">; stopSequences?: string[]; systemPrompt?: string; temperature?: number; } & { [k: string]: unknown; }

Returns

Promise<SamplingResponse>

---

setMaxListeners()

setMaxListeners(n: number): this;

Defined in: node_modules/.pnpm/@types+node@20.19.19/node_modules/@types/node/events.d.ts:814

By default EventEmitters will print a warning if more than 10 listeners are added for a particular event. This is a useful default that helps finding memory leaks. The emitter.setMaxListeners() method allows the limit to be modified for this specific EventEmitter instance. The value can be set to Infinity (or 0) to indicate an unlimited number of listeners.

Returns a reference to the EventEmitter, so that calls can be chained.

Parameters

Parameter	Type
n	number

Returns

this

Since

v0.3.5

Inherited from

FastMCPSessionEventEmitter.setMaxListeners