#Module: app

#Classes

#AppClientError

#Extends

• Error

#Constructors

#Constructor

new AppClientError(code, message, options?): AppClientError

#Parameters

#code

AppClientErrorCode

#message

string

#options?

Readonly<{ data?: JsonValue; rpcCode?: number; }>

#Returns

AppClientError

#Overrides

Error.constructor

#Properties

#~effect/ErrorReporter/attributes?

readonly optional ~effect/ErrorReporter/attributes?: ReadonlyRecord<string, unknown>

#Inherited from

Error.~effect/ErrorReporter/attributes

#~effect/ErrorReporter/ignore?

readonly optional ~effect/ErrorReporter/ignore?: boolean

#Inherited from

Error.~effect/ErrorReporter/ignore

#~effect/ErrorReporter/severity?

readonly optional ~effect/ErrorReporter/severity?: Severity

#Inherited from

Error.~effect/ErrorReporter/severity

#~effect/Runtime/errorExitCode?

readonly optional ~effect/Runtime/errorExitCode?: number

#Inherited from

Error.~effect/Runtime/errorExitCode

#~effect/Runtime/errorReported?

readonly optional ~effect/Runtime/errorReported?: boolean

#Inherited from

Error.~effect/Runtime/errorReported

#cause?

optional cause?: unknown

#Inherited from

Error.cause

#code

readonly code: AppClientErrorCode

#data?

readonly optional data?: JsonValue

#message

message: string

#Inherited from

Error.message

#name

name: string

#Inherited from

Error.name

#rpcCode?

readonly optional rpcCode?: number

#stack?

optional stack?: string

#Inherited from

Error.stack

#stackTraceLimit

static stackTraceLimit: number

The Error.stackTraceLimit property specifies the number of stack frames collected by a stack trace (whether generated by new Error().stack or Error.captureStackTrace(obj)).

The default value is 10 but may be set to any valid JavaScript number. Changes will affect any stack trace captured after the value has been changed.

If set to a non-number value, or set to a negative number, stack traces will not capture any frames.

#Inherited from

Error.stackTraceLimit

#Methods

#captureStackTrace()

static captureStackTrace(targetObject, constructorOpt?): void

Creates a .stack property on targetObject, which when accessed returns a string representing the location in the code at which Error.captureStackTrace() was called.

const myObject = {};
Error.captureStackTrace(myObject);
myObject.stack;  // Similar to `new Error().stack`

The first line of the trace will be prefixed with ${myObject.name}: ${myObject.message}.

The optional constructorOpt argument accepts a function. If given, all frames above constructorOpt, including constructorOpt, will be omitted from the generated stack trace.

The constructorOpt argument is useful for hiding implementation details of error generation from the user. For instance:

function a() {
  b();
}

function b() {
  c();
}

function c() {
  // Create an error without stack trace to avoid calculating the stack trace twice.
  const { stackTraceLimit } = Error;
  Error.stackTraceLimit = 0;
  const error = new Error();
  Error.stackTraceLimit = stackTraceLimit;

  // Capture the stack trace above function b
  Error.captureStackTrace(error, b); // Neither function c, nor b is included in the stack trace
  throw error;
}

a();

#Parameters

#targetObject

object

#constructorOpt?

Function

#Returns

void

#Inherited from

Error.captureStackTrace

#prepareStackTrace()

static prepareStackTrace(err, stackTraces): any

#Parameters

#err

Error

#stackTraces

CallSite[]

#Returns

any

#See

https://v8.dev/docs/stack-trace-api#customizing-stack-traces

#Inherited from

Error.prepareStackTrace

#Interfaces

#AppAbortSignal

#Properties

#aborted

readonly aborted: boolean

#Methods

#addEventListener()

addEventListener(type, listener, options?): void

#Parameters

#type

"abort"

#listener

() => void

#options?

Readonly<{ once?: boolean; }>

#Returns

void

#removeEventListener()

removeEventListener(type, listener): void

#Parameters

#type

"abort"

#listener

() => void

#Returns

void

#AppClient

#Properties

#connected

readonly connected: boolean

#disposed

readonly disposed: boolean

#Methods

#call()

call<Id>(routeId, input, options?): Promise<AppRouteResult<Id>>

#Type Parameters

#Id

Id extends `tool:${string}/${string}`

#Parameters

#routeId

Id

#input

AppRouteInput<Id>

#options?

AppRequestOptions

#Returns

Promise<AppRouteResult<Id>>

#connect()

connect(options?): Promise<AppInitializeResult>

#Parameters

#options?

AppRequestOptions

#Returns

Promise<AppInitializeResult>

#dispose()

dispose(): void

#Returns

void

#onToolCancelled()

onToolCancelled(listener): () => void

#Parameters

#listener

AppToolCancelledListener

#Returns

() => void

#onToolError()

onToolError<Id>(routeId, listener): () => void

#Type Parameters

#Id

Id extends `tool:${string}/${string}`

#Parameters

#routeId

Id

#listener

AppToolErrorListener

#Returns

() => void

#onToolInput()

onToolInput<Id>(routeId, listener): () => void

#Type Parameters

#Id

Id extends `tool:${string}/${string}`

#Parameters

#routeId

Id

#listener

AppToolInputListener<Id>

#Returns

() => void

#onToolResult()

onToolResult<Id>(routeId, listener): () => void

#Type Parameters

#Id

Id extends `tool:${string}/${string}`

#Parameters

#routeId

Id

#listener

AppToolResultListener<Id>

#Returns

() => void

#rebind()

rebind(options?): Promise<AppInitializeResult>

#Parameters

#options?

AppConnectOptions

#Returns

Promise<AppInitializeResult>

#request()

request<Result>(method, params?, options?): Promise<Result>

#Type Parameters

#Result

Result extends JsonValue = JsonValue

#Parameters

#method

string

#params?

JsonObject

#options?

AppRequestOptions

#Returns

Promise<Result>

#AppConnectOptions

#Extended by

• CreateAppClientOptions

#Properties

#parent?

readonly optional parent?: AppMessageTarget

#targetOrigin?

readonly optional targetOrigin?: string

#window?

readonly optional window?: AppWindow

#AppImplementation

#Properties

#name

readonly name: string

#version

readonly version: string

#AppInitializeResult

#Extends

• JsonObject

#Indexable

[key: string]: JsonValue

#Properties

#hostCapabilities

readonly hostCapabilities: JsonObject

#hostContext

readonly hostContext: JsonObject

#hostInfo

readonly hostInfo: JsonObject

#protocolVersion

readonly protocolVersion: "2026-01-26"

#AppMessageEvent

#Properties

#data

readonly data: unknown

#origin

readonly origin: string

#source

readonly source: unknown

#AppMessageTarget

#Methods

#postMessage()

postMessage(message, targetOrigin): void

#Parameters

#message

JsonObject

#targetOrigin

string

#Returns

void

#AppRegister

Project-generated declarations augment this interface with routes.

#AppRequestOptions

#Properties

#signal?

readonly optional signal?: AppAbortSignal

#timeoutMs?

readonly optional timeoutMs?: number

#AppRouteContract

#Properties

#input

readonly input: unknown

#result

readonly result: unknown

#AppWindow

#Properties

#parent

readonly parent: AppMessageTarget

#Methods

#addEventListener()

addEventListener(type, listener): void

#Parameters

#type

"message"

#listener

(event) => void

#Returns

void

#removeEventListener()

removeEventListener(type, listener): void

#Parameters

#type

"message"

#listener

(event) => void

#Returns

void

#CreateAppClientOptions

#Extends

• AppConnectOptions

#Properties

#appCapabilities?

readonly optional appCapabilities?: JsonObject

#appInfo?

readonly optional appInfo?: AppImplementation

#parent?

readonly optional parent?: AppMessageTarget

#Inherited from

AppConnectOptions.parent

#targetOrigin?

readonly optional targetOrigin?: string

#Inherited from

AppConnectOptions.targetOrigin

#timeoutMs?

readonly optional timeoutMs?: number

#window?

readonly optional window?: AppWindow

#Inherited from

AppConnectOptions.window

#Type Aliases

#AppClientErrorCode

AppClientErrorCode = "timeout" | "aborted" | "disposed" | "connection-rebound" | "invalid-message" | "rpc" | "capability-unavailable" | "consent-required"

#AppRouteId

AppRouteId = unknown extends AppRoutes ? `tool:${string}/${string}` : Extract<keyof AppRoutes, `tool:${string}/${string}`> & string

#AppRouteInput

AppRouteInput<Id> = Id extends keyof AppRoutes ? AppRoutes[Id] extends AppRouteContract ? AppRoutes[Id]["input"] : unknown : unknown

What a caller sends for one route: the registered inputSchema input type (defaults optional, transforms as the wire carries them), before the server parses it.

#Type Parameters

#Id

Id extends string

#AppRouteResult

AppRouteResult<Id> = Id extends keyof AppRoutes ? AppRoutes[Id] extends AppRouteContract ? AppRoutes[Id]["result"] : unknown : unknown

The structured result one route resolves with: the registered resultSchema output.

#Type Parameters

#Id

Id extends string

#AppRoutes

AppRoutes = AppRegister extends object ? Routes extends { readonly [Id in keyof Routes]: AppRouteContract } ? Routes : never : unknown

#AppToolCancelledListener

AppToolCancelledListener = (event) => Promise<void> | void

#Parameters

#event

Readonly<{ reason?: string; }>

#Returns

Promise<void> | void

#AppToolErrorListener

AppToolErrorListener = (error) => Promise<void> | void

#Parameters

#error

AppClientError

#Returns

Promise<void> | void

#AppToolInputListener

AppToolInputListener<Id> = (input) => Promise<void> | void

#Type Parameters

#Id

Id extends string

#Parameters

#input

AppRouteInput<Id>

#Returns

Promise<void> | void

#AppToolResultListener

AppToolResultListener<Id> = (result) => Promise<void> | void

#Type Parameters

#Id

Id extends string

#Parameters

#result

AppRouteResult<Id>

#Returns

Promise<void> | void

#Variables

#APP_PROTOCOL_VERSION

const APP_PROTOCOL_VERSION: "2026-01-26" = "2026-01-26"

#createAppClient

const createAppClient: (options?) => AppClient

#Parameters

#options?

CreateAppClientOptions

#Returns

AppClient