sdk_scroll · UI Bridge MCP: Risk & Policy

WHAT IT DOES

What sdk_scroll does on UI Bridge MCP

AI agents invoke sdk_scroll to trigger actions in UI Bridge MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why sdk_scroll needs a policy

Scrolling is an active UI operation that affects the state of an external application's interface. It is not purely read-only (it changes the viewport/scroll position and may trigger lazy-loading of content or other side effects), and it's not destructive. It falls under Execute as it performs a browser/UI action whose effects depend on the target element and scroll parameters.

From the tool's definition 'Scroll within an element in the SDK app' — triggers a UI interaction (scroll action) in an external application

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

sdk_scroll Rate-limited

sdk_scroll stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "sdk_scroll": {
      "limits": [
        {
          "counter": "sdk_scroll_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches UI Bridge MCP, so you can run agents against it safely.

FAQ

Questions about sdk_scroll

What does the sdk_scroll tool do? +

Scroll within an element in the SDK app. It is categorised as a Execute tool in the UI Bridge MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on sdk_scroll? +

Register the UI Bridge MCP server in PolicyLayer and add a rule for sdk_scroll: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches UI Bridge MCP. Nothing to install.

What risk level is sdk_scroll? +

sdk_scroll is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit sdk_scroll? +

Yes. Add a rate_limit block to the sdk_scroll rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block sdk_scroll completely? +

Set action: deny in the PolicyLayer policy for sdk_scroll. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides sdk_scroll? +

sdk_scroll is provided by the UI Bridge MCP server (qontinui/ui-bridge-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.