---
title: "Renderer options"
description: "Every option of <GistUI> and mount(), shared by the React, Vue, Svelte, Solid and vanilla renderers."
---

> Documentation Index
> Fetch the complete documentation index at: https://gistui.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Renderer options

The same options exist in every renderer: as props on `<GistUI>`, or as options of `mount()` in vanilla JavaScript.

## Input

| Option | Type | Notes |
|---|---|---|
| `stream` | `ReadableStream \| AsyncIterable` | Text or bytes. The renderer reads it. |
| `source` | `string` | A growing string. Only the appended part is parsed. |
| `streaming` | `boolean` | With `source`: whether more text is coming. |
| `inline` | `boolean` | The text is chat text with `gistui` fences. |
| `library` | `Library` | Required in React and vanilla (`ui`). Optional in Vue, Svelte and Solid, which default to the built-in one. |
| `components` | map | Vue, Svelte, Solid: components that replace built-in ones. |

Use `stream`, or `source` + `streaming`, not both.

## Callbacks

| React, Solid, vanilla | Vue | Svelte | Receives |
|---|---|---|---|
| `onAction` | `@action` | `onaction` | An [action](/docs/guides/actions-and-forms/) |
| `onError` | `@error` | `onerror` | Diagnostics, as they are found |
| `onStateChange` | `@stateChange` | `onstatechange` | State after a change |
| `onProse` | `@prose` | `onprose` | Prose lines the model wrote around the program |
| `onAutofix` | `@autofix` | `onautofix` | `{ changes, errors }` after a repair |
| `onToolCall` | `onToolCall` (prop) | `ontoolcall` | `{ name, args, kind, nodeId }`; return `false` to block |

## Appearance

| Option | Type | Default |
|---|---|---|
| `theme` | `"system" \| "light" \| "dark"` | `"system"` |
| `color` | a preset name | the catalog default |
| `tokens` | theme tokens | none |
| `darkTokens` | theme tokens for dark | none |
| `classNames` | classes per component | none |

See [Theming](/docs/guides/theming/).

## Behaviour

| Option | Type | Default | Notes |
|---|---|---|---|
| `initialState` | object | `{}` | Starting values for `$state` variables |
| `lockUntil` | `"done" \| "ready"` | `"done"` | When interactive parts unlock: at the end of the stream, or as each part completes |
| `openLinks` | `boolean` | `true` | `false` stops `@open` from opening links itself; you still get the `open` action |
| `paused` | `boolean` | `false` | Stops timed data refreshes |
| `autofix` | `boolean` | `true` | Repairs a finished program in code |

## Tools and safety

| Option | Type | Notes |
|---|---|---|
| `tools` | functions, or `{ callTool }` | Read-only. `@query` may call them as soon as the UI renders. |
| `mutations` | functions | Run only when a person presses a button. |
| `allowedHosts` | `string[]` | Hosts that images, video and backgrounds may load from. `*.example.com` matches subdomains. |
| `favicons` | `boolean \| string` | Site icons on `Source` cards. Off by default. A string is a URL with `{host}`. |

See [Security](/docs/guides/security/).

## Vanilla: the mount handle

```ts
const view = mount(element, options);
view.update(partialOptions); // change any option later
view.destroy();
```

Source: https://gistui.com/docs/reference/renderer-options/index.mdx