# UISandbox (npm · uisandbox-mcp)

Play with your app's design in the browser: load a build, turn the knobs, export the code.

- Trust score: 80/100 (high trust)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-20

## Components

- npm · `uisandbox-mcp`: 80/100 (this document), [markdown](https://verifymcp.io/servers/ideelab-uisandbox/uisandbox-mcp.md), [page](https://verifymcp.io/servers/ideelab-uisandbox/uisandbox-mcp)

## Channel facts

- Registry: `npm`
- Package: `uisandbox-mcp`
- Version: `0.3.3`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-20.

- **Supply Chain Security**: 98/100
  - No malware found by supply-chain analysis.
  - No known CVEs affecting this package version or its production dependencies.
  - No install/post-install scripts declared.
  - 31 of 97 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 48/100
  - Source repository is publicly reachable at the declared URL.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 20 days ago).
  - Publishes a security disclosure policy (SECURITY.md).
- **Schema Quality & AI Usability**: 83/100
  - 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 980 tokens (~122/item across 8 items; 8 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 70/100
  - Stability observed for 21 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 75/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 25% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 8 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 9 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### How do I install the UISandbox MCP server?

UISandbox runs locally as an npm package, launched with npx -y uisandbox-mcp. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add ideelab-uisandbox -- npx -y uisandbox-mcp
```

### Cursor

```json
{
  "mcpServers": {
    "ideelab-uisandbox": {
      "command": "npx",
      "args": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "ideelab-uisandbox": {
      "command": "npx",
      "args": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add ideelab-uisandbox -- npx -y uisandbox-mcp
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "ideelab-uisandbox": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "uisandbox-mcp"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add ideelab-uisandbox --command npx --arg -y --arg uisandbox-mcp
```

### Hermes

```yaml
mcp_servers:
  ideelab-uisandbox:
    command: "npx"
    args: ["-y", "uisandbox-mcp"]
```

### Netclaw

```json
{
  "McpServers": {
    "ideelab-uisandbox": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add ideelab-uisandbox -t stdio -c npx -a -y uisandbox-mcp
```

### Other

```json
{
  "mcpServers": {
    "ideelab-uisandbox": {
      "command": "npx",
      "args": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
```

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-20 (score 80, +1)

No change was recorded against any check on this day. Stability & Change Management went from 67 to 70. That category is still filling its 30-day observation window: 20 days of observed history at the previous scan, 21 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-18 (score 79, +1)

No change was recorded against any check on this day. Stability & Change Management went from 60 to 63. That category is still filling its 30-day observation window: 18 days of observed history at the previous scan, 19 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-16 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 53 to 57. That category is still filling its 30-day observation window: 16 days of observed history at the previous scan, 17 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-13 (score 77, +1)

No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-11 (score 76, +1)

No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-09 (score 75, +1)

No change was recorded against any check on this day. Stability & Change Management went from 30 to 33. That category is still filling its 30-day observation window: 9 days of observed history at the previous scan, 10 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-07 (score 74, +4)

- [functional improvement] Stability: unverified → 0.27

### 2026-08-31 (score 70, +15)

- [security improvement] Malware scan: unverified → pass

## MCP tools (8)

### `load` (~114 tokens)

Load a built web app

Load a BUILT web app (a zip of its dist/build/out folder, or a repo zip carrying the build) by URL or local path. Returns the project id, screens, tokenised values and the baseline the knobs stand on. Refuses what cannot render (iOS/Android/source-only) with the reason.

Input parameters:

- `zipPath` (string): Local path to the zip
- `zipUrl` (string): URL of the zip (any URL the server can fetch, incl. GitHub /archive/…zip)

### `screens` (~25 tokens)

List screens

The screens (HTML entries) of a loaded project.

Input parameters:

- `id` (string, required)

### `set` (~64 tokens)

Turn the knobs

Apply knobs to a loaded project. Every dial has ×1 (or 0) = as in their code; colours are #rrggbb. Returns what moved (count and a sample of value → value).

Input parameters:

- `id` (string, required)
- `knobs` (object, required)

### `export` (~76 tokens)

Export

Export the current state: sheet-css (your values as CSS custom properties), sheet-json, patch (literal → value list), tokens-css / tokens-json / tailwind / shadcn (the --k-* design tokens), swift, android-xml, android-kotlin.

Input parameters:

- `format` (string, required)
- `id` (string, required)

### `open` (~143 tokens)

Open the sandbox

Open UISandbox in the user's browser with this project loaded — the real, interactive sandbox: the whole app rendered 1:1, every knob there to turn by hand. Use this whenever the user wants to SEE or PLAY with the design themselves ("can I look at this in a sandbox", "let me try some changes"), not only read numbers. Served from 127.0.0.1 by this process; nothing leaves the machine. What the user turns in the browser flows back here: a later `export`, `verify` or `screenshot` uses it.

Input parameters:

- `id` (string, required)
- `screen` (string): Screen path to open first

### `state` (~36 tokens)

Current knobs

The knobs as they stand now — including what the user turned by hand in an opened sandbox (and when).

Input parameters:

- `id` (string, required)

### `verify` (~91 tokens)

Check 1:1

Run the 1:1 check in a real browser: the untouched build vs. the tokenised build with the identity sheet, computed styles of every element diffed. Also returns the reach meter. This is the same check a visitor runs on uisandbox.org.

Input parameters:

- `id` (string, required)
- `screen` (string): Screen path (from screens); default the first
- `width` (integer)

### `screenshot` (~46 tokens)

Screenshot

A PNG of the screen as it renders with the current knobs (the sandbox frame only).

Input parameters:

- `id` (string, required)
- `screen` (string)
- `width` (integer)

## Diagnostics

Captured diagnostic sections: Provenance, Dependencies. The full working is on the page: https://verifymcp.io/servers/ideelab-uisandbox/uisandbox-mcp#diagnostics

## Score history

- 2026-09-20: 80
- 2026-09-19: 79
- 2026-09-18: 79
- 2026-09-17: 78
- 2026-09-16: 78
- 2026-09-15: 77
- 2026-09-14: 77
- 2026-09-13: 77
- 2026-09-12: 76
- 2026-09-11: 76
- 2026-09-10: 75
- 2026-09-09: 75
- 2026-09-08: 74
- 2026-09-07: 74
- 2026-09-06: 70
- 2026-09-05: 70
- 2026-09-04: 70
- 2026-09-03: 70
- 2026-09-02: 70
- 2026-09-01: 70
- 2026-08-31: 70
- 2026-08-30: 55

## Common questions

### What is the UISandbox MCP server?

UISandbox is an MCP server listed in the public MCP registry as io.github.Ideelab/uisandbox. Play with your app's design in the browser: load a build, turn the knobs, export the code. This page covers its npm package (uisandbox-mcp).

### Is the UISandbox MCP server safe to use?

UISandbox scores 80 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 20 September 2026. It declares no install or post-install scripts. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the UISandbox MCP server expose?

UISandbox exposes 8 tools: load, screens, set, export, open, and 3 more. Their descriptions and schemas cost roughly 595 tokens of context every time the server is loaded.

### Is the UISandbox MCP server still maintained?

UISandbox is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What licence is the UISandbox MCP server under?

UISandbox declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

## Links

- npm package: https://www.npmjs.com/package/uisandbox-mcp
- Socket report: https://socket.dev/npm/package/uisandbox-mcp
- Repository: https://github.com/Ideelab/uisandbox
- Website: https://uisandbox.org/
- Changelog RSS feed: https://verifymcp.io/servers/ideelab-uisandbox/uisandbox-mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/ideelab-uisandbox/uisandbox-mcp.json
- HTML version of this page: https://verifymcp.io/servers/ideelab-uisandbox/uisandbox-mcp