# Use the assistant

Ask the AI assistant to build or change your design, point it at parts, attach a sketch or a data sheet, and undo what it did.

> **AI credit.** This feature uses AI credit. AI help is pay-as-you-go. No compulsory subscription. Drawing by hand is free for personal use. To add credit, open the account menu in the app. Prices: https://kerfcraft.app/pricing

Give the assistant sizes, materials and clearances. "A 900 wide, 1800 high bookcase in 18 mm birch plywood with four shelves" gets a better result than "a tall bookcase". To learn what it can and cannot do, read [How the assistant works](/docs/explanation/how-the-assistant-works/).

## Ask for a change

1. If the assistant panel is closed, click **◀ AI** at the right edge of the window.
2. Type your request in the box at the bottom of the panel.
3. Press Enter.

Each command that the assistant runs shows as a card in the chat, and the change shows in the model. Click a card to see the values that it used.

## Point at the parts you mean

1. Select the parts in the 3D view or in the **Model** list. They show as chips above the box.
2. To add a part by name, type **@** and the first letters of its name.
3. To stop the assistant from changing anything else, select **Only change these**.

## Attach a sketch, a photo or a data sheet

Paste or drag a JPEG, PNG, WebP or PDF onto the box, or click **📎**. A PDF data sheet of a hinge or a runner is useful: the assistant reads its text and drawings.

You can attach up to 4 files to a message, and up to 2 of them can be PDFs. Each PDF can have up to 30 pages and 4 MB. A PDF makes each later request cost more until you start a new chat.

## Allow or deny a paid action

An AI video, a restyle or a material preview costs credit in addition to the request. The assistant asks first, and shows the price.

- Click **Allow** to make it.
- Click **Deny** to stop it. You pay nothing for that action.

Read each request before you click **Allow**. A project from another person can contain text that tells the assistant to do things you did not ask for.

## Undo or change a request

- To stop a request, click **Stop**. The changes made so far stay.
- To remove every change from your last message, click **Undo last request**.
- To change a message and run it again, click **Edit** on the message, change the text and click **Save and re-run**. This also removes the later conversation.

## Start a new chat

Each request sends the whole conversation again, so a long conversation costs more. Click **New chat** to start again. Your design does not change, but you cannot get the old conversation back.