ui_type · Shotter MCP: Risk & Policy

WHAT IT DOES

What ui_type does on Shotter

AI agents invoke ui_type to trigger actions in Shotter. 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 ui_type needs a policy

Typing text into a simulator UI is an external action that modifies the state of the running application (e.g., fills form fields, sends messages, triggers searches). While it doesn't directly delete data or move money, it executes an operation with real effects inside the simulator environment.

From the tool's definition 'Type text into the iOS Simulator' — triggers an external operation (keyboard input) on a running simulator, whose effects depend on the text argument and the currently focused field.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ui_type Rate-limited

ui_type 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": {
    "ui_type": {
      "limits": [
        {
          "counter": "ui_type_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 Shotter, so you can run agents against it safely.

FAQ

Questions about ui_type

What does the ui_type tool do? +

Type text into the iOS Simulator. The text field must already be focused. Only supports ASCII printable characters. It is categorised as a Execute tool in the Shotter MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on ui_type? +

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

What risk level is ui_type? +

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

Can I rate-limit ui_type? +

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

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

ui_type is provided by the Shotter MCP server (nathanstitt/shotter). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.