ContextFragmentConfig

SUPPORT · interface · 类型合同

Self-describing fragment declaration: metadata plus a formatter.

导入

TypeScript

import type { ContextFragmentConfig } from '@jangts/agent-core/support';

JavaScript

/** @typedef {import('@jangts/agent-core/support').ContextFragmentConfig} ContextFragmentConfig */

其他公开入口：@jangts/agent-core、@jangts/agent-core/types、@jangts/agent-core/structs、@jangts/agent-core/support、@jangts/agent-core/support/context。

定义

interface ContextFragmentConfig<Input>

继承或实现： Omit<ContextFragment, 'value'>。

泛型参数

类型参数	约束	默认类型
Input	—	—

字段结构

字段	类型	必需	说明
description	string | undefined	可省略	只读。Documentation only; not sent to the model.
format	(input: Input) => ContextFragment["value"]	必需	只读。Produces the value; must be synchronous.
id	string	必需	Unique, stable id matching ^[a-z][a-zA-Z0-9:._-]*$; duplicates are rejected.
role	"system" | "user"	必需	Message slot the fragment occupies when assembled.
sourceId	string	必需	Owning source (module or registration) used to explain where the content came from.
trust	ContextTrust	必需	Producer trust level. user and tool content cannot become a system message.
lifetime	ContextLifetime	必需	Declared validity window of this content.
maxChars	number	必需	Hard upper bound in JSON characters; must be a positive safe integer.

成员目录

成员	用途
format	Produces the value; must be synchronous.

成员详情

format

Produces the value; must be synchronous.

ContextFragmentConfig.format(input: Input): ContextFragment["value"]

参数	类型	传递	说明
input	Input	必需	—

返回： string \| Record<string, unknown>。

使用示例

• 上下文装配：稳定元数据配置一次：Support 提前绑定片段元数据、格式化和顺序，请求只提供变化的业务输入。

一次配置，以后只给问题和历史

入门 · Node.js

TypeScript

import { Support } from '@jangts/agent-core';
type Input = { question: string; history: readonly { role: string; content: string }[] };
const builder = Support.defineContextFragments<Input>([
  { id: 'question', sourceId: 'request', trust: 'user', lifetime: 'turn', maxChars: 1000,
    role: 'user', format: input => input.question },
  { id: 'history', sourceId: 'conversation', trust: 'user', lifetime: 'turn', maxChars: 10000,
    role: 'user', format: input => ({ messages: input.history }) },
], { maxInputChars: 1200 });
const context = builder.build({ input: { question: '服务状态？', history: [] } });
console.log(context.messages);

JavaScript

import { Support } from '@jangts/agent-core';
const builder = Support.defineContextFragments([
    { id: 'question', sourceId: 'request', trust: 'user', lifetime: 'turn', maxChars: 1000,
        role: 'user', format: input => input.question },
    { id: 'history', sourceId: 'conversation', trust: 'user', lifetime: 'turn', maxChars: 10000,
        role: 'user', format: input => ({ messages: input.history }) },
], { maxInputChars: 1200 });
const context = builder.build({ input: { question: '服务状态？', history: [] } });
console.log(context.messages);

同一个 builder 提前给出计划

配置 · Node.js

TypeScript

import { Support } from '@jangts/agent-core';
type Input = { question: string; history: readonly { role: string; content: string }[] };
const builder = Support.defineContextFragments<Input>([
  { id: 'question', sourceId: 'request', trust: 'user', lifetime: 'turn', maxChars: 1000,
    role: 'user', format: input => input.question },
  { id: 'history', sourceId: 'conversation', trust: 'user', lifetime: 'turn', maxChars: 10000,
    role: 'user', format: input => ({ messages: input.history }) },
], { maxInputChars: 1200 });
const input = { question: '服务状态？', history: [] };
const plan = builder.plan({ input });
const expanded = builder.fragments(input);
console.log(plan.maxInputChars, expanded.map(fragment => fragment.id));
const largerRequest = builder.build({ input, maxInputChars: 2000 });
console.log(largerRequest.maxInputChars);

JavaScript

import { Support } from '@jangts/agent-core';
const builder = Support.defineContextFragments([
    { id: 'question', sourceId: 'request', trust: 'user', lifetime: 'turn', maxChars: 1000,
        role: 'user', format: input => input.question },
    { id: 'history', sourceId: 'conversation', trust: 'user', lifetime: 'turn', maxChars: 10000,
        role: 'user', format: input => ({ messages: input.history }) },
], { maxInputChars: 1200 });
const input = { question: '服务状态？', history: [] };
const plan = builder.plan({ input });
const expanded = builder.fragments(input);
console.log(plan.maxInputChars, expanded.map(fragment => fragment.id));
const largerRequest = builder.build({ input, maxInputChars: 2000 });
console.log(largerRequest.maxInputChars);

相关策略源码

• 装配顺序、依赖快照与请求预算覆盖

相关定义

• ContextFragment
• ContextLifetime
• ContextTrust