scout_new_tab · Scout MCP: Risk & Policy

WHAT IT DOES

What scout_new_tab does on Scout

AI agents invoke scout_new_tab to trigger actions in Scout. 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 scout_new_tab needs a policy

Opening a new tab and navigating to arbitrary URLs constitutes executing browser operations whose effects depend on the URL argument. While not destructive or financial, it can trigger external code execution (page scripts, third-party services) and manipulate user sessions. Classified as Execute rather than Write because it invokes browser operations rather than creating/modifying structured data.

From the tool's definition Tool opens a new browser tab and can navigate to a URL. This is an external operation that modifies browser state and can trigger page loads with side effects (scripts, tracking, redirects, etc.).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

scout_new_tab Rate-limited

scout_new_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": {
    "scout_new_tab": {
      "limits": [
        {
          "counter": "scout_new_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 Scout, so you can run agents against it safely.

FAQ

Questions about scout_new_tab

What does the scout_new_tab tool do? +

Open a new browser tab, optionally navigating to a URL. It is categorised as a Execute tool in the Scout MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on scout_new_tab? +

Register the Scout MCP server in PolicyLayer and add a rule for scout_new_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 Scout. Nothing to install.

What risk level is scout_new_tab? +

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

Can I rate-limit scout_new_tab? +

Yes. Add a rate_limit block to the scout_new_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 scout_new_tab completely? +

Set action: deny in the PolicyLayer policy for scout_new_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 scout_new_tab? +

scout_new_tab is provided by the Scout MCP server (lautrek/scout). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.