Tools & MCP

functionTool

function functionTool(def: ToolDefinition<P>): FunctionTool<P>

Create a callable FunctionTool the agent can expose to its model. Pass a ToolDefinition describing the tool; name is required. The argument schema can be a Zod schema (input, which takes precedence, or parameters directly) or a plain JSON Schema (parameters); Zod schemas are converted to JSON Schema.

def

ToolDefinition<P>

required

returns

FunctionTool<P>

isFunctionTool

function isFunctionTool(obj: any): obj is FunctionTool

Type guard: whether obj is a FunctionTool (has valid _toolInfo).

obj

any

required

returns

obj is FunctionTool

getToolInfo

function getToolInfo(tool: FunctionTool | any): FunctionToolInfoLike

Return the FunctionToolInfoLike metadata attached to a tool.

tool

FunctionTool | any

required

returns

FunctionToolInfoLike

FunctionTool

A callable tool: a function that runs the tool, with its FunctionToolInfoLike metadata attached as _toolInfo. Create one with functionTool.

type FunctionTool = { (args: P, ctx?: ToolContext): any | Promise<any>; _toolInfo: FunctionToolInfoLike; }

FunctionToolInfo

Concrete carrier for tool metadata; see FunctionToolInfoLike.

Constructor

new FunctionToolInfo(info: FunctionToolInfoLike)

info

FunctionToolInfoLike

required

ToolChoice

How the model is allowed to use tools on a turn.

enum ToolChoice {
  AUTO = 'auto',
  NONE = 'none',
  REQUIRED = 'required',
}

buildOpenaiSchema

function buildOpenaiSchema(tool: FunctionTool | any): { type: 'function'; function: { name: string; description: string; parameters: object }; }

Convert a tool to the OpenAI function-calling schema.

tool

FunctionTool | any

required

returns

{ type: 'function'; function: { name: string; description: string; parameters: object }; }

buildGeminiSchema

function buildGeminiSchema(tool: FunctionTool | any): { name: string; description: string; parameters: object; }

Convert a tool to the Gemini function-declaration schema (simplified parameters).

tool

FunctionTool | any

required

returns

{ name: string; description: string; parameters: object; }

buildNovaSonicSchema

function buildNovaSonicSchema(tool: FunctionTool | any): { type: 'function'; function: { name: string; description: string; parameters: object }; }

Convert a tool to the Nova Sonic schema (identical to OpenAI’s).

tool

FunctionTool | any

required

returns

{ type: 'function'; function: { name: string; description: string; parameters: object }; }

MCPServerStdio

Describe an MCP server run as a local subprocess communicating over stdio.

Constructor

new MCPServerStdio(command: string, opts: MCPServerStdioOptions)

command

string

required

Executable to launch.

args

string[] | null

Command-line arguments passed to the MCP server process. Default: [].

env

Record<string, string> | null

Environment variables for the MCP server process. Default: {}.

MCPServerHTTP

Describe an MCP server reached over HTTP.

Constructor

new MCPServerHTTP(url: string, opts: MCPServerHTTPOptions)

url

string

required

Base URL of the MCP server.

headers

Record<string, string> | null

HTTP headers sent with each request to the MCP server. Default: {}.

DTMFHandler

Create a DTMFHandler.

Constructor

new DTMFHandler(_opts: Record<string, any>)

_opts

Record<string, any>

default:"{}"

onDigit

onDigit(digit: string, callback: DTMFCallback): void

digit

string

required

callback

DTMFCallback

required

onSequence

onSequence(sequence: string, callback: DTMFCallback): void

sequence

string

required

callback

DTMFCallback

required

VoiceMailDetector

Create a VoiceMailDetector.

Constructor

new VoiceMailDetector(opts: VoiceMailDetectorOptions)

llm

any

LLM used for classification. Default: null.

callback

VoiceMailCallback | null

Callback fired on detection. Default: null.

duration

number

Detection window in seconds. Default: 2.0. Overridden by VoiceMailDetectorOptions.maxDetectionSeconds when set.

customPrompt

string | null

Custom classifier prompt; falls back to the built-in prompt when empty. Default: ''.

autoHangup

boolean

Hang up automatically when voicemail is detected. Default: false.

detectionThreshold

number

Confidence threshold (0-1) required to count as a detection. Default: 1.0.

maxDetectionSeconds

number | null

Maximum detection window in seconds; takes precedence over VoiceMailDetectorOptions.duration. Default: null.

Node JS SDK

Core

Speech-to-text

LLM

Text-to-speech

Realtime models

Avatars

Turn detection

Voice activity detection

Noise cancellation

functionTool

isFunctionTool

getToolInfo

FunctionTool

FunctionToolInfo

Constructor

ToolChoice

buildOpenaiSchema

buildGeminiSchema

buildNovaSonicSchema

MCPServerStdio

Constructor

MCPServerHTTP

Constructor

DTMFHandler

Constructor

onDigit

onSequence

VoiceMailDetector

Constructor

​functionTool

​isFunctionTool

​getToolInfo

​FunctionTool

​FunctionToolInfo

​Constructor

​ToolChoice

​buildOpenaiSchema

​buildGeminiSchema

​buildNovaSonicSchema

​MCPServerStdio

​Constructor

​MCPServerHTTP

​Constructor

​DTMFHandler

​Constructor

​onDigit

​onSequence

​VoiceMailDetector

​Constructor

functionTool

isFunctionTool

getToolInfo

FunctionTool

FunctionToolInfo

Constructor

ToolChoice

buildOpenaiSchema

buildGeminiSchema

buildNovaSonicSchema

MCPServerStdio

Constructor

MCPServerHTTP

Constructor

DTMFHandler

Constructor

onDigit

onSequence

VoiceMailDetector

Constructor