The CLI that AI agents call

import { execSync } from "node:child_process";
import Anthropic from "@anthropic-ai/sdk";

function nib(cmd: string) {
    return JSON.parse(execSync(`nib ${cmd}`).toString());
}

const client = new Anthropic();

async function agentStep(task: string, window: string) {
    // 1. Observe — snapshot the UI
    const { data } = nib(`snapshot --window "${window}" -i`);

    // 2. Decide — let the LLM pick an action
    const response = await client.messages.create({
        model: "claude-sonnet-4-5-20250929",
        system: `You control a desktop via nib commands.
Available elements:\n${data.refs.join("\n")}`,
        messages: [{ role: "user", content: task }],
        tools: nibTools,
    });

    // 3. Act — execute the command
    const tool = response.content.find(b => b.type === "tool_use");
    nib(`${tool.name} ${tool.input.ref} --window "${window}"`);

    // 4. Verify — diff to confirm the effect
    return nib(`diff --window "${window}"`);
}

# Take a baseline snapshot
$ nib snapshot --window "Settings" -i

# Perform an action
$ nib click-element @chk:DarkMode --window "Settings"

# Compare current state against the last snapshot
$ nib diff --window "Settings"

{
  "ok": true,
  "command": "diff",
  "data": {
    "added": [
      "@btn:Restart"
    ],
    "removed": [],
    "changed": [
      {
        "ref": "@chk:DarkMode",
        "isChecked": { "from": false, "to": true }
      }
    ]
  }
}