ModelInputMeasurement

CORE · interface · Type contract

Exact prepared-request accounting; token values exist only with an explicit model counter.

Import

TypeScript

import type { ModelInputMeasurement } from '@jangts/agent-core/model';

JavaScript

/** @typedef {import('@jangts/agent-core/model').ModelInputMeasurement} ModelInputMeasurement */

Other public entry points:@jangts/agent-core, @jangts/agent-core/model, @jangts/agent-core/types, @jangts/agent-core/structs.

Definition

interface ModelInputMeasurement

Field structure

Field	Type	Required	Description
messageChars	number	Required	Read-only. Characters of the message content.
instructionChars	number	Required	Read-only. Characters of the instruction text.
schemaChars	number	Required	Read-only. Characters of the compiled capability schemas.
transportChars	number	Required	Read-only. Characters the transport itself contributes (for example framing).
inputChars	number	Required	Read-only. Sum of the character components above.
maxInputChars	number	Required	Read-only. Character budget the input was compared against.
maxSchemaChars	number	Required	Read-only. Schema budget the input was compared against.
maxOutputTokens	number	Required	Read-only. Output tokens reserved for this call, which reduces the token input ceiling.
counterId	string | undefined	Optional	Read-only. Tokenizer identity; present only when a token budget applies.
inputTokens	number | undefined	Optional	Read-only. Measured input tokens.
inputTokenLimit	number | undefined	Optional	Read-only. Token ceiling after reserving output and the safety margin.
withinBudget	boolean	Required	Read-only. True when every applicable character and token budget accepted the input.

Examples

• Actual request measurement and same-call preparation snapshot: Use prepare only when context must be handled ahead of time; multiple measurements and the final send reuse the same transport preparation.

Ordinary calls still only use invoke

Beginner · Node.js

TypeScript

import { ModelRunner } from '@jangts/agent-core/model';
const provider = {
  async *stream(messages: readonly { content: string }[]) {
    yield '收到：' + messages.at(-1)!.content;
  },
};
const runner = new ModelRunner({ provider });
console.log((await runner.invoke('你好')).value);

JavaScript

import { ModelRunner } from '@jangts/agent-core/model';
const provider = {
    async *stream(messages) {
        yield '收到：' + messages.at(-1).content;
    },
};
const runner = new ModelRunner({ provider });
console.log((await runner.invoke('你好')).value);

Prepare once only when measurement is needed

Configuration · Node.js

TypeScript

import { ModelRunner } from '@jangts/agent-core/model';
const provider = {
  async *stream(messages: readonly { content: string }[]) {
    yield '收到：' + messages.at(-1)!.content;
  },
};
const runner = new ModelRunner({ provider, maxInputChars: 1000 });
const prepared = runner.prepare({ stageId: 'reply', maxOutputTokens: 400 });
const input = '你好，解释这次服务状态';
console.log(prepared.measure(input));
const result = await runner.invoke({ input, prepared });
console.log(result.value);

JavaScript

import { ModelRunner } from '@jangts/agent-core/model';
const provider = {
    async *stream(messages) {
        yield '收到：' + messages.at(-1).content;
    },
};
const runner = new ModelRunner({ provider, maxInputChars: 1000 });
const prepared = runner.prepare({ stageId: 'reply', maxOutputTokens: 400 });
const input = '你好，解释这次服务状态';
console.log(prepared.measure(input));
const result = await runner.invoke({ input, prepared });
console.log(result.value);

Related policy source

• Same-call preparation and real input measurement