# Sketch

> A drawing canvas inside the agent composer.

- Area: Desktop app
- Plans: All plans
- Last checked against the product: 2026-09-08
- Web page: https://agentsroom.dev/docs/sketch

## What it does

A drawing canvas inside the agent composer. Open a blank canvas to sketch a mockup, a wireframe or a diagram, or open an image already in the composer to annotate it: circle the bug, draw an arrow, highlight a region, add text. **Attach to message** exports the drawing as a PNG and drops it in the composer's file tray; it travels with your next message like any attached image, so an agent whose model reads images sees the drawing instead of parsing a paragraph of description.

## Where to find it

- The **Sketch** button in the composer toolbar of any agent (tooltip "A sketch is worth a thousand words").
- On an image thumbnail in the composer tray: the pencil button **Edit in sketch canvas**.
- In the file preview of an image: **Annotate**.

## How to use it

1. Click **Sketch**. A fullscreen canvas opens with the rectangle tool already active, ready to frame an element.
2. Draw: freehand, rectangles, ellipses, arrows, lines, text.
3. Click **Attach to message** (disabled until something is drawn). The PNG appears as a numbered thumbnail (`File #N`) in the tray.
4. Write your prompt and send: the image goes with the message.

Annotating an existing image: drop a screenshot in the composer (or capture one with [Screenshot to Agent](https://agentsroom.dev/docs/screenshot-to-agent.md)), click the pencil on its thumbnail. The image is the background layer; draw on top, attach, and the annotated version replaces the original thumbnail so the agent never receives the image twice. Closing a modified canvas asks for confirmation.

## Settings

- `composerHiddenActions` (global, Settings > Composer > Composer toolbar buttons): hide the **Sketch** button if you never use it.

## Agent tools (MCP)

None. The sketch reaches the agent as a plain image attachment.

## Providers

All providers whose model accepts image input: the attachment is a standard PNG passed by path, with no provider-specific logic. A text-only model receives the file path without being able to see it.

## Mobile

Not available on the mobile companion. The phone can attach photos and screenshots to the focused desktop agent, without an annotation canvas.

## Limits

- Sketches are saved locally in your home folder, outside the project, and purged after seven days: they are context for one message, not documents to keep.
- SVG files cannot be annotated (vector, not rasterizable); the pencil is hidden for them.
- If the canvas fonts fail to load, text falls back to system fonts; drawings are unaffected.

## Common questions

- **Does the agent really see my sketch?** Yes, as long as its model accepts images (Claude Code, Codex and the other multimodal CLIs).
- **Can I re-edit a sketch?** Yes: any image in the tray, including an annotated one, reopens in the canvas via the pencil.
- **Do I need Excalidraw, Figma or a screenshot tool?** No: the canvas is inside the composer, no export, no drag back in.
- **Is anything uploaded?** The PNG is sent to the agent with your message, like any attached file, and nowhere else.

## Related

- [Screenshot to Agent](https://agentsroom.dev/docs/screenshot-to-agent.md): capture a screen region first, then annotate it with Sketch.
- [File Preview](https://agentsroom.dev/docs/file-preview.md): the **Annotate** entry point on a previewed image.
- [Figma to AI Agents](https://agentsroom.dev/docs/figma-to-ai-agents.md): send a Figma frame instead of a hand drawing.