Your existing Selenium tests, running against a browser that understands what you meant when the selector breaks.

# LLM fallback re-resolves when CSS misses.
from selenium import webdriver
from selenium.webdriver.common.by import By

opts = webdriver.ChromeOptions()
opts.set_capability(
    "lumabyte:llmFallback",
    {"enabled": True}
)
driver = webdriver.Remote(
    "http://127.0.0.1:9515", options=opts
)

# Option A: keep CSS, add an AI hint
button = driver.execute(
    "find element",
    {"using": "css selector",
     "value": "button.btn-primary.signup",
     "lumabyte:description": "the sign-up button"}
)["value"]

# Option B: skip CSS entirely
button = driver.find_element(
    "ai-description", "the sign-up button"
)
button.click()

// LLM fallback re-resolves when CSS misses.
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Remote;

var opts = new ChromeOptions();
opts.AddAdditionalOption(
    "lumabyte:llmFallback",
    new Dictionary<string, object> { { "enabled", true } }
);

var driver = new RemoteWebDriver(
    new Uri("http://127.0.0.1:9515"), opts
);

// Option A: keep CSS, add an AI hint (vendor param
// rides along on the find-element command).
var found = driver.ExecuteCustomDriverCommand(
    DriverCommand.FindElement,
    new Dictionary<string, object> {
        { "using", "css selector" },
        { "value", "button.btn-primary.signup" },
        { "lumabyte:description", "the sign-up button" }
    }
);

// Option B: skip CSS entirely.
var button = driver.FindElement(
    By.Custom("ai-description", "the sign-up button")
);
button.Click();

// LLM fallback re-resolves when CSS misses.
const { Builder, By } = require('selenium-webdriver');
const chrome = require('selenium-webdriver/chrome');

const opts = new chrome.Options();
opts.set('lumabyte:llmFallback', { enabled: true });

const driver = await new Builder()
  .usingServer('http://127.0.0.1:9515')
  .forBrowser('chrome')
  .setChromeOptions(opts)
  .build();

const { Command } = require('selenium-webdriver/lib/command');

// Option A: keep CSS, add an AI hint.
const foundA = await driver.execute(
  new Command('findElement')
    .setParameter('using', 'css selector')
    .setParameter('value', 'button.btn-primary.signup')
    .setParameter('lumabyte:description', 'the sign-up button')
);

// Option B: skip CSS, dispatch the ai-description strategy directly.
const foundB = await driver.execute(
  new Command('findElement')
    .setParameter('using', 'ai-description')
    .setParameter('value', 'the sign-up button')
);
// foundB is a raw element reference; wrap or click via the executor.

# One call returns URL, title, source, and
# (optionally) a full-page screenshot.
from selenium.webdriver.remote.command import Command

# Register the vendor command once per driver.
driver.command_executor._commands["lumabyteSnapshot"] = (
    "POST", "/session/$sessionId/lumabyte/dom/snapshot"
)

snap = driver.execute(
    "lumabyteSnapshot",
    {"includeScreenshot": True}
)["value"]
# 1 request. Parse locally.

// One call returns URL, title, source, and
// (optionally) a full-page screenshot.
using OpenQA.Selenium.Remote;

// ExecuteCustomDriverCommand dispatches a vendor verb
// without polluting CommandInfoRepository at the caller.
var snap = driver.ExecuteCustomDriverCommand(
    "lumabyte:dom/snapshot",
    new Dictionary<string, object> {
        { "includeScreenshot", true }
    }
);
// 1 request. Parse locally.

// One call returns URL, title, source, and
// (optionally) a full-page screenshot.
const { Command } = require('selenium-webdriver/lib/command');

// Teach the executor about the vendor verb once.
driver.getExecutor().defineCommand(
  'lumabyteSnapshot',
  'POST',
  '/session/:sessionId/lumabyte/dom/snapshot'
);

const snap = await driver.execute(
  new Command('lumabyteSnapshot')
    .setParameter('includeScreenshot', true)
);
// 1 request. Parse locally.

# LumaBrowser is already running.
# Connect directly.
from selenium import webdriver

driver = webdriver.Remote(
    "http://127.0.0.1:9515",
    options=webdriver.ChromeOptions()
)

# No binary download.
# No version pinning.
# No child process.

// LumaBrowser is already running.
// Connect directly.
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Remote;

var driver = new RemoteWebDriver(
    new Uri("http://127.0.0.1:9515"),
    new ChromeOptions()
);

// No binary download.
// No version pinning.
// No child process.

// LumaBrowser is already running.
// Connect directly.
const { Builder } = require('selenium-webdriver');

const driver = await new Builder()
  .usingServer('http://127.0.0.1:9515')
  .forBrowser('chrome')
  .build();

// No binary download.
// No version pinning.
// No child process.