type_text · Mcp Desktop MCP: Risk & Policy

WHAT IT DOES

What type_text does on Mcp Desktop

AI agents invoke type_text to trigger actions in Mcp Desktop. 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 type_text needs a policy

Typing arbitrary text into a focused UI element constitutes an external operation with variable effects depending on the target app and content. It could submit forms, execute commands in a terminal, send messages, modify documents, or trigger any UI action. This goes beyond a simple write since the effects are entirely context-dependent and could trigger destructive or financial actions in the target application.

From the tool's definition 'Type a string of text as keyboard input into the currently focused element' — injects arbitrary keyboard input into whatever application has focus

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

type_text Rate-limited

type_text 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": {
    "type_text": {
      "limits": [
        {
          "counter": "type_text_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 Mcp Desktop, so you can run agents against it safely.

FAQ

Questions about type_text

What does the type_text tool do? +

Type a string of text as keyboard input into the currently focused element. Pass verify_app to confirm the right app is frontmost before typing. It is categorised as a Execute tool in the Mcp Desktop MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on type_text? +

Register the Mcp Desktop MCP server in PolicyLayer and add a rule for type_text: 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 Mcp Desktop. Nothing to install.

What risk level is type_text? +

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

Can I rate-limit type_text? +

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

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

type_text is provided by the Mcp Desktop MCP server (mocha06/mcp-desktop). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.