一次绑定，单次多模型与跨次切换

构造时提供稳定模型配置；请求用配置 ID 选择，不反复注入 Provider。

单模型可在构造时传 model 配置，或稍后 bindModel 一次。多模型则在 models 中登记配置，model 字符串选择默认项；多个模型时不能猜默认值。未知模型 ID 在调用前拒绝。

switchModel 改后续运行的默认选择；run(state,{modelId}) 只覆盖本次，节点 model.invoke({modelId}) 只覆盖这次模型调用。单次 Workflow 可先快模型草拟、再另一个模型复核。多模型共享 maxModelCalls 请求预算，每个模型仍有各自的局部限制；切换不刷新祖先额度。

模型配置与选择绑定在 Agent 上，Workflow 通过节点中的模型端口使用它们。

由简到繁的同业务示例

将模型提前绑到 Agent

入门 · Node.js

TypeScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
type State = { input: string; answer?: string };
const workflow = defineWorkflow<State, string>({ id: 'chat', nodes: [{
  id: 'reply', description: '用绑定模型回答', startsRound: true,
  async run(state, { model }) {
    const { value } = await model.invoke({ input: state.input });
    return { answer: value };
  }, routes: [route.deliver('answer')],
}] });
const provider = {
  async *stream(messages: readonly { content: string }[]) {
    yield '收到：' + messages.at(-1)!.content;
  },
};
const agent = new AgentCoreEngine({ workflow, model: { provider } });
console.log(await agent.run({ input: '你好' }));

JavaScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
const workflow = defineWorkflow({ id: 'chat', nodes: [{
            id: 'reply', description: '用绑定模型回答', startsRound: true,
            async run(state, { model }) {
                const { value } = await model.invoke({ input: state.input });
                return { answer: value };
            }, routes: [route.deliver('answer')],
        }] });
const provider = {
    async *stream(messages) {
        yield '收到：' + messages.at(-1).content;
    },
};
const agent = new AgentCoreEngine({ workflow, model: { provider } });
console.log(await agent.run({ input: '你好' }));

增加模型目录，调用时只给 ID

配置 · Node.js

TypeScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
type State = { input: string; answer?: string };
const workflow = defineWorkflow<State, string>({ id: 'chat', nodes: [{
  id: 'reply', description: '用绑定模型回答', startsRound: true,
  async run(state, { model }) {
    const { value } = await model.invoke({ input: state.input });
    return { answer: value };
  }, routes: [route.deliver('answer')],
}] });
const provider = {
  async *stream(messages: readonly { content: string }[]) {
    yield '收到：' + messages.at(-1)!.content;
  },
};
const agent = new AgentCoreEngine({ workflow, model: 'quick', maxModelCalls: 4,
  models: { quick: { provider, maxCalls: 2 }, careful: { provider, maxCalls: 2 } },
});
console.log(await agent.run({ input: '简答' }));
console.log(await agent.run({ input: '仔细回答' }, { modelId: 'careful' }));
agent.switchModel('careful');
console.log(await agent.run({ input: '后续默认使用 careful' }));

JavaScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
const workflow = defineWorkflow({ id: 'chat', nodes: [{
            id: 'reply', description: '用绑定模型回答', startsRound: true,
            async run(state, { model }) {
                const { value } = await model.invoke({ input: state.input });
                return { answer: value };
            }, routes: [route.deliver('answer')],
        }] });
const provider = {
    async *stream(messages) {
        yield '收到：' + messages.at(-1).content;
    },
};
const agent = new AgentCoreEngine({ workflow, model: 'quick', maxModelCalls: 4,
    models: { quick: { provider, maxCalls: 2 }, careful: { provider, maxCalls: 2 } },
});
console.log(await agent.run({ input: '简答' }));
console.log(await agent.run({ input: '仔细回答' }, { modelId: 'careful' }));
agent.switchModel('careful');
console.log(await agent.run({ input: '后续默认使用 careful' }));

同一任务中调用两个已绑定模型

扩展 · Node.js

TypeScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
type State = { input: string; answer?: string };
const provider = {
  async *stream(messages: readonly { content: string }[]) {
    yield '收到：' + messages.at(-1)!.content;
  },
};
const workflow = defineWorkflow<State, string>({ id: 'draft-review', nodes: [{
  id: 'reply', description: '草拟后复核', startsRound: true,
  async run(state, { model }) {
    const draft = await model.invoke({ input: state.input, modelId: 'quick' });
    const reviewed = await model.invoke({ input: '复核这份草稿：' + draft.value, modelId: 'careful' });
    return { answer: reviewed.value };
  }, routes: [route.deliver('answer')],
}] });
const agent = new AgentCoreEngine({ workflow, model: 'quick', maxModelCalls: 2,
  models: { quick: { provider }, careful: { provider } },
});
console.log(await agent.run({ input: '解释服务状态' }));

JavaScript

import { AgentCoreEngine, defineWorkflow, route } from '@jangts/agent-core/engine';
const provider = {
    async *stream(messages) {
        yield '收到：' + messages.at(-1).content;
    },
};
const workflow = defineWorkflow({ id: 'draft-review', nodes: [{
            id: 'reply', description: '草拟后复核', startsRound: true,
            async run(state, { model }) {
                const draft = await model.invoke({ input: state.input, modelId: 'quick' });
                const reviewed = await model.invoke({ input: '复核这份草稿：' + draft.value, modelId: 'careful' });
                return { answer: reviewed.value };
            }, routes: [route.deliver('answer')],
        }] });
const agent = new AgentCoreEngine({ workflow, model: 'quick', maxModelCalls: 2,
    models: { quick: { provider }, careful: { provider } },
});
console.log(await agent.run({ input: '解释服务状态' }));