switch_tab · Mcp Desktop MCP: Risk & Policy

WHAT IT DOES

What switch_tab does on Mcp Desktop

AI agents invoke switch_tab 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 switch_tab needs a policy

Switching tabs is an active UI control operation that changes the state of a browser or terminal application. It's part of the 'full UI control' trust level described in the server description, and triggers an external operation (changing focus/active tab). While not destructive or financial, it enables navigation that could be a precursor to further automated actions, placing it in Execute rather than Write or Read.

From the tool's definition Switch to a tab in a browser or terminal. Matches by URL substring, then title substring, then index.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

switch_tab Rate-limited

switch_tab 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": {
    "switch_tab": {
      "limits": [
        {
          "counter": "switch_tab_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 switch_tab

What does the switch_tab tool do? +

Switch to a tab in a browser or terminal. Matches by URL substring, then title substring, then index. 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 switch_tab? +

Register the Mcp Desktop MCP server in PolicyLayer and add a rule for switch_tab: 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 switch_tab? +

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

Can I rate-limit switch_tab? +

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

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

switch_tab 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.