For AI agents: llms.txt is a short guide that sends you to the rules your problem needs, and rules.json holds every rule of this playbook as JSON.

How to do it

Write the progress first in the title, such as "Step 2 of 4 - Shipping address". List the steps in an ordered list, link the finished ones, and mark the current one with aria-current="step". Keep the step in the address, as state in the address describes, so Back and reload work. Save each step's answers when people move on. Never ask again for what an earlier step collected, as redundant entry requires. End with a review step before anything is charged or sent.

Examples

Using these examples: they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

TypeScript example

export function showStep(step: number, steps: string[], form: HTMLFormElement) {
  const title = `Step ${step} of ${steps.length} - ${steps[step - 1]}`;
  document.title = `${title} | Example Shop`;
  form.querySelector('h1')!.textContent = title;
  history.pushState({ step }, '', `?step=${step}`);
  form.querySelectorAll('.steps a').forEach((link, index) => {
    if (index === step - 1) link.setAttribute('aria-current', 'step');
    else link.removeAttribute('aria-current');
  });
}

Python example

from playwright.sync_api import expect

def test_back_keeps_earlier_answers(page):
    page.goto("https://staging.example.com/checkout?step=1")
    expect(page).to_have_title("Step 1 of 4 - Contact | Example Shop")
    page.get_by_label("Email").fill("ada@example.com")
    page.get_by_role("button", name="Next").click()
    expect(page).to_have_url("https://staging.example.com/checkout?step=2")
    page.go_back()
    expect(page.get_by_label("Email")).to_have_value("ada@example.com")
    expect(page.get_by_role("link", name="Contact")).to_have_attribute("aria-current", "step")

How to check

A browser test fills steps 1 and 2, presses the browser's Back button, and finds step 1 with its values and its own address. It reloads step 2, and the values are still there. Every step's title starts with "Step N of M".

Sources

• W3C WAI tutorial on multi-page forms
• WCAG 2.2 criterion 3.3.7 Redundant Entry
• WAI-ARIA 1.2 on aria-current

Related rules

• Keep screen state in the address in App interface
• Never ask for the same thing twice in Website