LoopEvent

CORE · interface · Type contract

Progress fact for one loop round, correlated with the enclosing diagnostics span.

Import

TypeScript

import type { LoopEvent } from '@jangts/agent-core/engine';

JavaScript

/** @typedef {import('@jangts/agent-core/engine').LoopEvent} LoopEvent */

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

Definition

interface LoopEvent

Field structure

Field	Type	Required	Description
eventId	string	Required	Read-only. Unique id of this fact.
type	"error" | "complete" | "enter" | "continue"	Required	Read-only. enter opens a round, continue/complete close it, error reports failure.
roundIndex	number	Required	Read-only. Zero-based round index; a new round starts only when the step asks to continue.
phase	"boundary" | "run" | "budget" | undefined	Optional	Read-only. Phase that failed on error: boundary checks, the step itself, or budget accounting.
errorCode	string | undefined	Optional	Read-only. Stable error classification when type is error.

Examples

• Process observation and node reports: The App subscribes to Core execution facts; nodes report their own usedModel and use an instance sub-logger to record intent first and then results, while the Loop owns identity and logging.

Observe the nodes and model events a task passes through

Beginner · Node.js

TypeScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';

type State = { name: string; answer?: string };
const workflow = defineWorkflow<State, string>({
  id: 'greeting',
  nodes: [{
    id: 'greet', description: '根据本次姓名生成问候', startsRound: true,
    run: state => ({ answer: '你好，' + state.name }),
    routes: [route.deliver('answer')],
  }],
});
const agent = new AgentCoreEngine({ workflow, execution: {
  observe: { event(event) { console.log(event.type, event.eventId); } },
} });
console.log(await agent.run({ name: 'Ivan' }));

JavaScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
const workflow = defineWorkflow({
    id: 'greeting',
    nodes: [{
            id: 'greet', description: '根据本次姓名生成问候', startsRound: true,
            run: state => ({ answer: '你好，' + state.name }),
            routes: [route.deliver('answer')],
        }],
});
const agent = new AgentCoreEngine({ workflow, execution: {
        observe: { event(event) { console.log(event.type, event.eventId); } },
    } });
console.log(await agent.run({ name: 'Ivan' }));

Report a business stage while the node executes

Configuration · Node.js

The node only reports facts it knows; Core owns node identity and execution association.

TypeScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
type State = { name: string; answer?: string };
const workflow = defineWorkflow<State, string>({ id: 'greeting', nodes: [{
  id: 'greet', description: '生成问候', startsRound: true,
  run(state, context) {
    context.report({ payload: { phase: 'formatting' } });
    return { answer: '你好，' + state.name };
  }, routes: [route.deliver('answer')],
}] });
const agent = new AgentCoreEngine({ workflow, execution: {
  observe: { event(event) { console.log(event.type); } },
} });
console.log(await agent.run({ name: 'Ivan' }));

JavaScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
const workflow = defineWorkflow({ id: 'greeting', nodes: [{
            id: 'greet', description: '生成问候', startsRound: true,
            run(state, context) {
                context.report({ payload: { phase: 'formatting' } });
                return { answer: '你好，' + state.name };
            }, routes: [route.deliver('answer')],
        }] });
const agent = new AgentCoreEngine({ workflow, execution: {
        observe: { event(event) { console.log(event.type); } },
    } });
console.log(await agent.run({ name: 'Ivan' }));

Related policy source

• Shared execution fact source and consumption isolation
• Sub-step statuses and their progression