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UISandbox

NPM · UISANDBOX-MCP · SCANNED SEP 20

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

Available components

+3 this week 80 Trust /100
Trust breakdown (7 categories)

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. How we score → Why this is hard to score →

Supply Chain Security98
  • No malware found by supply-chain analysis.Pass
  • No known CVEs affecting this package version or its production dependencies.Pass
  • No install/post-install scripts declared.Pass
  • 31 of 97 dependencies flagged as unhealthy. View diagnostics → Partial
Provenance & Transparency48
  • Source repository is publicly reachable at the declared URL. View diagnostics → Pass
  • Provenance check failed: no build-provenance attestation is published. See how to fix → View diagnostics → Fail
  • Clear OSI-approved license (MIT).Pass
  • Actively maintained (last published 20 days ago).Pass
  • Publishes a security disclosure policy (SECURITY.md).Pass
Schema Quality & AI Usability83
  • 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
  • AI-judged instruction clarity (good).Pass
  • 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. See how to fix → Fail
  • Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management70
  • Stability observed for 21 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage75
  • 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
  • 25% of tool parameters carry a description.Partial
Tool Safety100
  • No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
  • We read all 8 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
  • An AI judge read all 9 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
  • Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
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.

npm · uisandbox-mcp

# add to Claude Code
claude mcp add ideelab-uisandbox -- npx -y uisandbox-mcp
// .cursor/mcp.json
{
  "mcpServers": {
    "ideelab-uisandbox": {
      "command": "npx",
      "args": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
// .vscode/mcp.json
{
  "servers": {
    "ideelab-uisandbox": {
      "command": "npx",
      "args": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
# add to Codex CLI
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
    }
  }
}
# add to OpenClaw
openclaw mcp add ideelab-uisandbox --command npx --arg -y --arg uisandbox-mcp
# ~/.hermes/config.yaml
mcp_servers:
  ideelab-uisandbox:
    command: "npx"
    args: ["-y", "uisandbox-mcp"]
// ~/.netclaw/config/netclaw.json
{
  "McpServers": {
    "ideelab-uisandbox": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
# add to Vellum
assistant mcp add ideelab-uisandbox -t stdio -c npx -a -y uisandbox-mcp
// mcp.json
{
  "mcpServers": {
    "ideelab-uisandbox": {
      "command": "npx",
      "args": [
        "-y",
        "uisandbox-mcp"
      ]
    }
  }
}
Changelog

Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.

  • 20 Sept 26 +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.

  • 18 Sept 26 +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.

  • 16 Sept 26 +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.

  • 13 Sept 26 +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.

  • 11 Sept 26 +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.

  • 9 Sept 26 +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.

  • 7 Sept 26 +4
    • Stability: unverified → 0.27 functional
  • 31 Aug 26 +15
    • Malware scan: unverified → pass security
Diagnostics

Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.

Captured 20 Sept 2026 · Analysed npm/uisandbox-mcp@0.3.3

Provenance No attestation

The registry publishes no build provenance for this version, so there is nothing to verify.

Result No attestation
Ecosystem npm

Background: How many MCP packages publish verified provenance →

Dependencies 97 packages
Packages resolved 97
Stale 31
Tree resolution Complete

Background: SBOMs and build attestations, explained →

MCP tools · 8 exposed · ~595 tokens

The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →

Tool Tokens
export ~76

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.

NameTypeReqDescription
formatstringyes
idstringyes

No output schema declared.

No examples provided.

load ~114

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.

NameTypeReqDescription
zipPathstringLocal path to the zip
zipUrlstringURL of the zip (any URL the server can fetch, incl. GitHub /archive/…zip)

No output schema declared.

No examples provided.

open ~143

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.

NameTypeReqDescription
idstringyes
screenstringScreen path to open first

No output schema declared.

No examples provided.

screens ~25

The screens (HTML entries) of a loaded project.

NameTypeReqDescription
idstringyes

No output schema declared.

No examples provided.

screenshot ~46

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

NameTypeReqDescription
idstringyes
screenstring
widthinteger

No output schema declared.

No examples provided.

set ~64

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).

NameTypeReqDescription
idstringyes
knobsobjectyes

No output schema declared.

No examples provided.

state ~36

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

NameTypeReqDescription
idstringyes

No output schema declared.

No examples provided.

verify ~91

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.

NameTypeReqDescription
idstringyes
screenstringScreen path (from screens); default the first
widthinteger

No output schema declared.

No examples provided.

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.