open_new_tab · Selenium MCP: Risk & Policy

WHAT IT DOES

What open_new_tab does on SeleniumMCP

AI agents invoke open_new_tab to trigger actions in SeleniumMCP. 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 open_new_tab needs a policy

This tool triggers an external browser operation (opening a new tab and navigating to a URL), which is an Execute-category action. It performs a browser-level action with side effects that depend on the URL argument provided, such as loading external web content, executing page scripts, or initiating network requests.

From the tool's definition Open a new browser tab and optionally navigate it to a URL

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

open_new_tab Rate-limited

open_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": {
    "open_new_tab": {
      "limits": [
        {
          "counter": "open_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 SeleniumMCP, so you can run agents against it safely.

FAQ

Questions about open_new_tab

What does the open_new_tab tool do? +

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

How do I enforce a policy on open_new_tab? +

Register the Selenium MCP server in PolicyLayer and add a rule for open_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 SeleniumMCP. Nothing to install.

What risk level is open_new_tab? +

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

Can I rate-limit open_new_tab? +

Yes. Add a rate_limit block to the open_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 open_new_tab completely? +

Set action: deny in the PolicyLayer policy for open_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 open_new_tab? +

open_new_tab is provided by the Selenium MCP server (lokii0911/seleniummcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.