Copilotz vs LangChain.js

import { createAgent, tool } from "langchain";import * as z from "zod"; const getWeather = tool(  (input) => `It's always sunny in ${input.city}!`,  {    name: "get_weather",    description: "Get the weather for a given city",    schema: z.object({      city: z.string().describe("The city to get the weather for"),    }),  }); const agent = createAgent({  model: "claude-sonnet-4-6",  tools: [getWeather],}); console.log(  await agent.invoke({    messages: [{ role: "user", content: "What's the weather in San Francisco?" }],  }));

// From the README's salon.ts: one Action, three callers (excerpt).actions: {  "booking.make": defineAction({    input: booking,    // Asked of every caller, tools included: people, agents working for them, and contacts.    allow: peopleOrContacts,    run: (ctx, input) => ctx.db.collection("booking").insertOne(input),  }),},views: {  // What a model reads after it books, the app's own or one over MCP.  "tool:book": (_, ctx) => ctx.show("bookings", {}),},resources: {  // The rules: a booking lives in a space, and belongs to the chat it was made in.  shared: { booking: { part: "thread" } },  tools: {    book: tool({      description: "Books a slot, like 'Wed 15:00'.",      input: { type: "object", properties: { slot: { type: "string" } }, required: ["slot"] },      run: ({ slot }, ctx) => ctx.call("booking.make", { slot, in: ctx.in, thread: ctx.thread }),    }),  },  agents: {    concierge: { instructions: "Book slots.", model: "openai/gpt-5.4-mini", tools: ["book"] },  },  // An MCP server at /mcp/salon. No sign-in: each conversation is a contact, in its own chat.  mcp: { salon: { in: "desk", tools: { book: {} } } },},