Form input purpose

Standards already define how a form tells software what each field wants. WCAG 2.2 SC 1.3.5 Identify Input Purpose (level AA) requires the purpose of fields that collect information about the user to be programmatically determinable, so that user agents can present and autofill it. In HTML that is the autocomplete attribute, whose WHATWG autofill field names include name, email, tel, street-address, postal-code, country, cc-name, cc-number, cc-exp, one-time-code, transaction-currency and transaction-amount. SC 3.3.2 Labels or Instructions (level A) requires labels or instructions wherever input is needed. SC 4.1.2 Name, Role, Value (level A) requires every control's name and role to be programmatically determinable and its state to be settable. These are the properties agents read from the accessibility tree; we located no agent vendor that documents using autocomplete tokens specifically.