Class: ContextWindowExceededError

Defined in: src/adapters/llm/contextWindow.ts:57

Thrown by an LLM adapter when the provider refused the request because the prompt did not fit the model's context window.

A refusal, not a failure of the model: nothing was generated and nothing was charged for output. Retrying the identical request is deterministic — it fails the same way — so this is one of the classes canResume reports as not resumable.

Example

import { ContextWindowExceededError } from 'agentfootprint';

try {
  await agent.run({ message: 'summarise the fabric inventory' });
} catch (err) {
  if (err instanceof ContextWindowExceededError) {
    console.error(`sent ${err.actualTokens} against ${err.limitTokens}`);
    // …cap the tool result, or add .window(slidingWindow({ keepRecentTurns: 2 }))
  }
}

Extends

Error

Constructors

Constructor

new ContextWindowExceededError(args): ContextWindowExceededError

Defined in: src/adapters/llm/contextWindow.ts:75

Parameters

args

actualTokens?

number

cause?

Error

limitTokens?

number

provider

string

providerMessage

string

status?

number

Returns

ContextWindowExceededError

Overrides

Error.constructor

Properties

actualTokens?

readonly optional actualTokens?: number

Defined in: src/adapters/llm/contextWindow.ts:67

What the request actually came to in tokens, when the vendor said it.

cause?

readonly optional cause?: Error

Defined in: src/adapters/llm/contextWindow.ts:73

The provider's own error, unchanged.

Overrides

Error.cause

code

readonly code: "ERR_CONTEXT_WINDOW_EXCEEDED" = ERR_CONTEXT_WINDOW_EXCEEDED

Defined in: src/adapters/llm/contextWindow.ts:58

limitTokens?

readonly optional limitTokens?: number

Defined in: src/adapters/llm/contextWindow.ts:64

The model's (or gateway's) ceiling in tokens, when the vendor said it.

message

message: string

Defined in: node_modules/typescript/lib/lib.es5.d.ts:1077

Inherited from

Error.message

name

name: string

Defined in: node_modules/typescript/lib/lib.es5.d.ts:1076

Inherited from

Error.name

provider

readonly provider: string

Defined in: src/adapters/llm/contextWindow.ts:61

Which adapter refused — 'openai', 'anthropic', 'bedrock', …

stack?

optional stack?: string

Defined in: node_modules/typescript/lib/lib.es5.d.ts:1078

Inherited from

Error.stack

stackTraceLimit

static stackTraceLimit: number

Defined in: node_modules/@types/node/globals.d.ts:67

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

status?

readonly optional status?: number

Defined in: src/adapters/llm/contextWindow.ts:70

HTTP status, when there was one. Kept so retry policies still see a 4xx.

Methods

captureStackTrace()

static captureStackTrace(targetObject, constructorOpt?): void

Defined in: node_modules/@types/node/globals.d.ts:51

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();

static prepareStackTrace(err, stackTraces): any

Defined in: node_modules/@types/node/globals.d.ts:55

ContextWindowExceededError

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