transformContextText

SUPPORT · function · 运行时值

Apply a text transform to a fragment value, including strings nested inside objects.

Structured values are walked through a JSON round trip, which is what the budget measurement serializes later; values that JSON cannot represent are therefore not preserved.

导入

TypeScript

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

JavaScript

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

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

定义

调用

transformContextText(fragment: ContextFragment, transform: (text: string) => string): ContextFragment

Apply a text transform to a fragment value, including strings nested inside objects.

Structured values are walked through a JSON round trip, which is what the budget measurement serializes later; values that JSON cannot represent are therefore not preserved.

参数	类型	传递	说明
fragment	ContextFragment	必需	—
transform	(text: string) => string	必需	—

fragment 的字段

字段	类型	必需	说明
id	string	必需	Unique, stable id matching ^[a-z][a-zA-Z0-9:._-]*$; duplicates are rejected.
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.
role	"system" | "user"	必需	Message slot the fragment occupies when assembled.
value	string | Record<string, unknown>	必需	Rendered content. A system message accepts a string only, never a record.

返回： ContextFragment。

返回值结构

字段	类型	必需	说明
id	string	必需	Unique, stable id matching ^[a-z][a-zA-Z0-9:._-]*$; duplicates are rejected.
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.
role	"system" | "user"	必需	Message slot the fragment occupies when assembled.
value	string | Record<string, unknown>	必需	Rendered content. A system message accepts a string only, never a record.

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);

复用元数据目录与请求贡献插槽

扩展 · Node.js

TypeScript

import { Support } from '@jangts/agent-core';
import type { ContextFragment } from '@jangts/agent-core/types';
type Input = { question: string; evidence: string };
const builder = Support.defineContextAssembly<Input, 'question', 'evidence'>([
  { kind: 'fragment', id: 'question', format: input => input.question },
  { kind: 'contributions', placement: 'evidence' },
], {
  maxInputChars: 2000,
  fragment(id, value): ContextFragment { return { id, sourceId: 'request', trust: 'user', lifetime: 'turn', role: 'user', maxChars: 1000, value }; },
  contributions: { evidence(input) { return [{ id: 'evidence', sourceId: 'service', trust: 'server', lifetime: 'turn', role: 'user', maxChars: 1000, value: input.evidence }]; } },
});
console.log(builder.build({ input: { question: '状态？', evidence: '最近检查：正常' } }).messages);

JavaScript

import { Support } from '@jangts/agent-core';
const builder = Support.defineContextAssembly([
    { kind: 'fragment', id: 'question', format: input => input.question },
    { kind: 'contributions', placement: 'evidence' },
], {
    maxInputChars: 2000,
    fragment(id, value) { return { id, sourceId: 'request', trust: 'user', lifetime: 'turn', role: 'user', maxChars: 1000, value }; },
    contributions: { evidence(input) { return [{ id: 'evidence', sourceId: 'service', trust: 'server', lifetime: 'turn', role: 'user', maxChars: 1000, value: input.evidence }]; } },
});
console.log(builder.build({ input: { question: '状态？', evidence: '最近检查：正常' } }).messages);

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