0013. The in-chat assistant bar

• Status: Accepted
• Date: 2026-10-26

Context

The AI assistant (#103) lives in a panel window: a person opens it, asks for replies, approves a preview of what is sent, picks a reply, and goes back to WhatsApp. The maintainer wants it in the chat itself (#407): reply suggestions right by the message box, a field to ask for a message in one's own words, and a way to send a suggestion with one click.

Two existing rules stand in the way. ADR 0004 keeps extensions out of WhatsApp's page, so no extension can draw over it, imitate it, or read what it does not hold a grant for. And extensions only insert drafts: no API sends a message. Both protect people from hostile or broken extensions, and they still should.

Decision

1. YapYap draws the bar, not the extension. The bar is a chrome view (app://chrome/assistant-bar.html, ADR 0001) that YapYap lays out in the main window directly beneath the active account's WhatsApp view, which it shortens by the bar's height. Nothing is injected into WhatsApp's page: WhatsApp cannot read, restyle or imitate the bar, and the bar keeps working whatever WhatsApp changes in its layout. It shows only while a extension holding assistant:bar for the account runs, and the user can hide it; it never covers WhatsApp.
2. Extensions fill it with plain text. An extension holding the new assistant:bar capability, granted per account like the others, calls host.assistant.offer({ chat, suggestions }) with up to five strings of at most 1,000 characters each. YapYap checks them against a schema and shows them as text, never markup, under the extension's name, and only while the chat they were made for is the open chat. The bar's Write a message field passes what the user types to the extension only when the user presses Enter in it (see 5).
3. Sending is YapYap's, on the user's click. Clicking a suggestion puts it in the message box, as composer:insert-draft already does. Its Send button, drawn by YapYap, replaces the draft with the suggestion and presses Enter in WhatsApp's message box, once per click, through webContents.sendInputEvent. No extension API sends a message, and nothing sends without a click in YapYap's own bar: an extension can only offer text.
4. Reading the chat stays behind the existing grants. The assistant still needs chat:read-active for the chat, still asks before it is used in a chat for the first time, and still sends only as many messages as Settings allows. The panel's preview of exactly what is sent becomes a setting, Show what is sent first, on by default for new chats.
5. Nothing happens on its own. The bar asks the extension for suggestions only when the user clicks Suggest replies or presses Enter in Write a message, as suggest and prompt events. No chat is read or sent anywhere because a message arrived, and the adapter still adds no observers to WhatsApp's page. Typing in WhatsApp's message box never waits for the bar, and the bar keeps its height while it waits, so WhatsApp's view does not jump.

Consequences

• ADR 0004 gains the assistant:bar capability and the rule that only YapYap's own interface sends a message, after a click.
• ADR 0001 gains the bar as a chrome view in the main window, with the same CSP, preload and sender checks as the sidebar.
• The panel stays for setup (provider, key, model) and for longer work, such as summaries.
• The bar is a second place where extension text appears in YapYap's own interface. It is always labelled with the extension's name, so it cannot pass for WhatsApp's or YapYap's own suggestions.

Amendments

• 2026-10-27 (#407): an offer is { suggestions, status, confirm }, with no chat. YapYap notes which chat was open when the user asked, so a extension cannot name another, and uses or sends a suggestion only while that chat is still open. confirm labels a button that sends the extension a confirm request, which the AI assistant uses to ask before a chat's messages first leave. The Show what is sent first setting is not built: the bar asks once per chat, and the assistant's panel keeps the full preview.