select_with_fallback

THE RISK

High Risk

Why select_with_fallback needs a policy

This tool triggers UI interactions (opening dropdowns and selecting options) via Accessibility APIs or Chrome DevTools Protocol. It performs active UI manipulation — an external operation whose effects depend on arguments — placing it in the Execute category. Misuse could cause unintended application state changes, but effects are generally reversible, warranting medium severity.

From the tool's definition 'Select an option from a dropdown/menu using the canonical fallback chain: AX → CDP. Finds the control, opens it, and picks the specified option.'

Documented attack patterns abuse exactly the kind of access select_with_fallback gives an agent:

POLICY

How to control select_with_fallback

PolicyLayer is an MCP gateway — it sits between your AI agents and ScreenHand, and nothing reaches the server without passing your rules. This is the rule we recommend for select_with_fallback:

policy.json

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

select_with_fallback 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.

Create a free account and register ScreenHand — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More ScreenHand tools

Destructive recording_cancel Cancel the current recording without saving. Destructive watch_unregister Remove a watch rule by ID. Execute applescript Run an AppleScript command. For controlling Finder, Safari, Mail, Notes, etc. (macOS only) Execute app_launch Launch a macOS/Windows application by bundle ID (e.g., Execute browser_js Execute JavaScript in a Chrome/Electron tab. Returns the result. WARNING: This runs arbitr Execute browser_navigate Navigate the active Chrome/Electron tab to a URL Execute browser_wait Wait for a condition on a Chrome/Electron page Execute launch Launch an application by bundle ID

All 89 ScreenHand tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

High-risk tools in ScreenHand → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about select_with_fallback

What does the select_with_fallback tool do? +

Select an option from a dropdown/menu using the canonical fallback chain: AX → CDP. Finds the control, opens it, and picks the specified option. It is categorised as a Execute tool in the ScreenHand MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on select_with_fallback? +

Register the ScreenHand MCP server in PolicyLayer and add a rule for select_with_fallback: 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 ScreenHand. Nothing to install.

What risk level is select_with_fallback? +

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

Can I rate-limit select_with_fallback? +

Yes. Add a rate_limit block to the select_with_fallback 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 select_with_fallback completely? +

Set action: deny in the PolicyLayer policy for select_with_fallback. 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 select_with_fallback? +

select_with_fallback is provided by the ScreenHand MCP server (manushi4/screenhand). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every ScreenHand tool call.

Start from ScreenHand, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →